Info for a 331/347 stroker build

[MattZ281LE]

Get a cam for 1.6 Rockers.

185's are good for a street 331, some may say 205's but your not looking for RPM's and 400rwhp.
Your HP goal is reasonable. 1 HP per CI for a good running well pieced combo is expected.
70-75mm TB MAX
Pro-M77 for NA cars is my choice
Cheap OTS cams...hmmmm. There are some . Ford and TFS are under 200.00 You get into Crower/Comp/Crane your well over 250.00-300.00 for an OTS grind. Best getting a custom.
Systemax is a nice choice...Im kicking myself in the ass for selling mine when i had the KB. (now i never get rid of anything)
30# Injectors
Bigger intank pump. std 255 is plenty even a 190lph
good tune.

Be aware, this is not a cheap build no matter what. Whatever you have budgeted or think you will spend, add 1/2 again or double it. All the little things...gaskets and headbolts, pilot bearings, motor mounts etc,etc that people forget about.
Im on my 3rd motor and 4th combo in 3 years Iv'e been through it all I think ecept Turbo (Mr. Eades may change my combo if he ever gets it to the dyno and track. )

 

[bimmertech]

alot of good info here.

i would like to emphasize the internal balance---i would not build an engine that isn't.

i also like the vic jr's---excellent bang for the buck.

just cuz its a street car doesn't mean you can't justify a alum flywheel. it isn't as noticeable on our cars(well mine anyways), but every other car i have put a lightweight flywheel on has had a very dramatic effect.

 

[stprorolla49]

Get a cam for 1.6 Rockers.

185's are good for a street 331, some may say 205's but your not looking for RPM's and 400rwhp.
Your HP goal is reasonable. 1 HP per CI for a good running well pieced combo is expected.
70-75mm TB MAX
Pro-M77 for NA cars is my choice
Cheap OTS cams...hmmmm. There are some . Ford and TFS are under 200.00 You get into Crower/Comp/Crane your well over 250.00-300.00 for an OTS grind. Best getting a custom.
Systemax is a nice choice...Im kicking myself in the ass for selling mine when i had the KB. (now i never get rid of anything)
30# Injectors
Bigger intank pump. std 255 is plenty even a 190lph
good tune.

Be aware, this is not a cheap build no matter what. Whatever you have budgeted or think you will spend, add 1/2 again or double it. All the little things...gaskets and headbolts, pilot bearings, motor mounts etc,etc that people forget about.
Im on my 3rd motor and 4th combo in 3 years Iv'e been through it all I think ecept Turbo (Mr. Eades may change my combo if he ever gets it to the dyno and track. )

Great info here, i really appreciate it! Im expecting to spend about $1500-1800 or so on the shortblock, about $1200 for the heads and rockers used, about $400 for the intake used, about $200-300 for the cam, about $400-500 for maf, inj, tb, about $300 for some used longtubes and shorty h-pipe, and prob around $500 in misc parts like head gaskets, oil pump, timing chain, etc. Then about $600 for either a dyno tune, or a PMS and do it myself. Does this sound about right?

 

[BlackVert]

Great info here, i really appreciate it! Im expecting to spend about $1500-1800 or so on the shortblock, about $1200 for the heads and rockers used, about $400 for the intake used, about $200-300 for the cam, about $400-500 for maf, inj, tb, about $300 for some used longtubes and shorty h-pipe, and prob around $500 in misc parts like head gaskets, oil pump, timing chain, etc. Then about $600 for either a dyno tune, or a PMS and do it myself. Does this sound about right?

don't forget lifters, pushrods, gaskets, and head bolts or studs. then there are things like motor mounts, spark plug wires, new coil, ... all that "other stuff" adds up fast.

are you getting a main girdle? if so, the block should be align honed with the girdle torqued down. similarly, the cylinders should be honed with a plate torqued onto it. that makes for a better honing job

 

[Zero Signal]

For used heads, I would make sure you plan to have them checked out (valve seats, giudes, deck flatness, etc). If your $1200 includes that, you'd be looking at used heads for ~$1000 assuming everything checks.

For the shortblock, I think $2000 would be more realistic. If it's done by a good local shop, expect closer to $2500. But if you are doing it yourself, remember the cost of tools and renting tools etc etc.

 

[stprorolla49]

For used heads, I would make sure you plan to have them checked out (valve seats, giudes, deck flatness, etc). If your $1200 includes that, you'd be looking at used heads for ~$1000 assuming everything checks.

For the shortblock, I think $2000 would be more realistic. If it's done by a good local shop, expect closer to $2500. But if you are doing it yourself, remember the cost of tools and renting tools etc etc.

I will be building the shortblock myself. I've already built a 350 small block chevy with my dad for his chevelle, so we've already got a ring compressor, torque wrenches, and pretty much every tool you can think of. Can some of you guys give me totals as to how much your motor builds have cost if you dont mind disclosing this info? As for this year, the car is just gonna get some ASP pullies, gears, axles, and new front struts. Everything else im saving for the motor which i'll probably start next winter.

 

[Zero Signal]

My shortblock ended up around $2500 including flywheel cut and balancer. It was about $1100 in labor I think.

 

[WhiteDevil]

Mine was $3,000 locally built

 

[BlackVert]

mine cost like 3500 just for machine work and labor

the rotating assembly and block was 1300

all the other stuff ran another 2-3 grand

but i got march brackets and polished stuff and kind of went all out with this build

i had pretty much everything done except for the roller cam bearings

 

[stprorolla49]

Damn, this is literally gonna take me like 4 years to save up for. For what im looking for, is a stroker really worth it over a 306? Please justify this for me... I mean, i can get some forged pistons, have the block bored out, and just do a nice h/c/i, and make maybe 20hp and 20-30ft/lbs less than a 331/347, and it will cost me a lot less money. Is this true? HELP!

 

[final5-0]

Damn, this is literally gonna take me like 4 years to save up for. For what im looking for, is a stroker really worth it over a 306? Please justify this for me... I mean, i can get some forged pistons, have the block bored out, and just do a nice h/c/i, and make maybe 20hp and 20-30ft/lbs less than a 331/347, and it will cost me a lot less money. Is this true? HELP!

I think your expectations might be a bit off IMHO

Here is a plan you might think about

With the combo focus mostly on street and a bit of strip activity ......
and
We're not talking about a high hp, purpose built race motor either.

This means you would be able to drive it around town with good street manners and you would keep the rpm between say 6 to 6500

302, 306, 331, or 347 ... it makes no difference if you have it built by a Pro, it is gonna be balanced and blueprinted. Since all specs are gonna be right, you will gain a bit of hp due to the motor is more efficient and you can go a bit higher with the rpm band.

Having said that ..... I'm trying to say this ...........
this shortblock will be a good bang for the buck
but
you would not want to turn high rpm or expect mega power from it.

You don't need fancy rods, pistons, crank, shaft rockers, of any other high dollar parts to build this shortblock.

You might want to upgrade some of the parts
but
the mind set here is .................

Again ... with the conditions set above ...................
You just don't need to choose the best of everything in the shortblock

Now about your thinking a stroker is gonna only produce 20-30 more hp/tq.

First ... more conditions here

Naturally Aspirated
Good Combo Parts Selection
Good Tune

1 rwhp for every cubic inch is not out of line for all conditions above
and
you could do a bit better if we're talkin about a weekend toy
because
you can then go a bit more aggressive with parts selection

So if you got a 306 and a 347 ......................

The difference could be "MORE" than your expectations

Just me thinkin out loud here

Grady

 

[stprorolla49]

I think your expectations might be a bit off IMHO

Here is a plan you might think about

With the combo focus mostly on street and a bit of strip activity ......
and
We're not talking about a high hp, purpose built race motor either.

This means you would be able to drive it around town with good street manners and you would keep the rpm between say 6 to 6500

302, 306, 331, or 347 ... it makes no difference if you have it built by a Pro, it is gonna be balanced and blueprinted. Since all specs are gonna be right, you will gain a bit of hp due to the motor is more efficient and you can go a bit higher with the rpm band.

Having said that ..... I'm trying to say this ...........
this shortblock will be a good bang for the buck
but
you would not want to turn high rpm or expect mega power from it.

You don't need fancy rods, pistons, crank, shaft rockers, of any other high dollar parts to build this shortblock.

You might want to upgrade some of the parts
but
the mind set here is .................

Again ... with the conditions set above ...................
You just don't need to choose the best of everything in the shortblock

Now about your thinking a stroker is gonna only produce 20-30 more hp/tq.

First ... more conditions here

Naturally Aspirated
Good Combo Parts Selection
Good Tune

1 rwhp for every cubic inch is not out of line for all conditions above
and
you could do a bit better if we're talkin about a weekend toy
because
you can then go a bit more aggressive with parts selection

So if you got a 306 and a 347 ......................

The difference could be "MORE" than your expectations

Just me thinkin out loud here

Grady

Grady, you are definately one of the most insightful people on this sight, and i truely appreciate it. This car is my daily driver and sees the track maybe once every 2 weeks over the summer because im at school in the spring and fall. That being said, im not looking for the most radical combo, im not looking to spin it over 6 grand, and im not looking to spend my life savings. Assuming i build a 306 with the stock crank and rods, and got some forged pistons, and essentially did a rebuild to a stock donor shortblock, and put some afr 165's, a perfomer/track heat/systemax intake, and a custom cam with a 70mm tb, 75mm maf, 24 lb inj, and a dyno tune, i could easily see 310 hp / 330 ft lbs correct.

I'll use Paul for example. He made i believe 310hp and 340 ft/lbs on a stock block with box stock afr 165's, performer intake, and an fti cam, and he ran 12.03 in a vert thats about 300-400 lbs more than my car. I'd like to see mid-low 12's with practice and good driveability. Would a 306 seem like a better compromise? My buddy has a 347 in his fox, and it hasnt given him anything but problems with driveability.

 

[Zero Signal]

Grady, you are definately one of the most insightful people on this sight, and i truely appreciate it. This car is my daily driver and sees the track maybe once every 2 weeks over the summer because im at school in the spring and fall. That being said, im not looking for the most radical combo, im not looking to spin it over 6 grand, and im not looking to spend my life savings. Assuming i build a 306 with the stock crank and rods, and got some forged pistons, and essentially did a rebuild to a stock donor shortblock, and put some afr 165's, a perfomer/track heat/systemax intake, and a custom cam with a 70mm tb, 75mm maf, 24 lb inj, and a dyno tune, i could easily see 310 hp / 330 ft lbs correct.

I'll use Paul for example. He made i believe 310hp and 340 ft/lbs on a stock block with box stock afr 165's, performer intake, and an fti cam, and he ran 12.03 in a vert thats about 300-400 lbs more than my car. I'd like to see mid-low 12's with practice and good driveability. Would a 306 seem like a better compromise? My buddy has a 347 in his fox, and it hasnt given him anything but problems with driveability.

If you rebuild, you might as well go stroker becuase the cost is about the same. I think the only difference is that you pay a few more bucks to have the block notched for the crank. IIRC one of the 347 parts was cheaper than the 306, I just can't remember what it was (maybe the crank ). But I talked to the builder about it and he knew right off the bat that they were both going to cost the same so I went for the cubes. As for the driveability, it's all in the tune and head/cam choice.

As for your RPM range and usage, you should stay away from a big runner head. If you're looking for really good flat 3k to 6k or 6.5k rpm torque curve you'll probably want to keep with a modest head in the 170-185cc on a 347/331 or 160-170 on a 306 then select a cam that gives you the torque curve you want. Remember; area under the curve goes a LONG way.

Once you start putting a big runner head and nasty cam on there, you run into other issues with supporting that power band (narrow, very high RPM) with your fuel system, valvetrain, ignition system, tune etc. If you go big and don't go all out and do it right, you'll have a lazy motor and spent money where you shouldn't have.

Whatever you decide one, be prepared to fork over some serious cash though. I make decent money and I still don't know how everyone can afford all this I felt really wierd spending the money on the shortblock as it is!

 

[stprorolla49]

If you rebuild, you might as well go stroker becuase the cost isn't much different. I think the only difference is you pay a few more bucks to have the block notched for the crank. As for the driveability, it's all in the tune and head/cam choice.

As for your RPM range and usage, you should stay away from a big runner head. If you're looking for really good flat 3k to 6k or 6.5k rpm torque curve you'll probably want to keep with a modest head in the 170-185cc on a 347/331 or 160-170 on a 306 then select a cam that gives you the torque curve you want. Remember; area under the curve goes a LONG way.

Once you start putting a big runner head and nasty cam on there, you run into other issues with supporting that power band (narrow, very high RPM) with your fuel system, valvetrain, ignition system, tune etc. If you go big and don't go all out and do it right, you'll have a lazy motor and spent money where you shouldn't have.

Your last paragraph there is exactly what im getting at. If im gonna build a stroker, im gonna max out on cubes (347), im gonna get a good rotating assembly with a cast crank, 4340 rods, 4340 forged pistons, afr 185's, systemax intake, probably a custom cam, a nice oil pan (ie moroso, milodon, etc), longtubes, bigger injectors, bigger maf, bigger tb, plus all the supporting things like rockers, afpr, gaskets, pushrods, lifters...god, the list goes on and on and on, but i would wanna do it right. Then im probably gonna run into spark issues like my buddy did with his pretty mild 347, and have to get a new ignition. Then i know for sure my t-5 probably wont last, and my rear wont last long.

Basically, give me more reasons why a 306 might be a better choice for a daily driven car. I'd save a few hundred on the shortblock, plus a few hundred in the h/c/i, plus save on not having to buy as big maf, tb, inj, plus save on reusing the stock pan. I would also not run longtubes because i dont want to replace my midpipe, and i have to go thru emissions every year where i swap my stock h-pipe in and pass perfectly, so i'd be running shorties. I would also be ok with my stock ignition, and really only have to change the fuel pump to a 255lph and throw an afpr on there as far as the fueling system would go.

I'm not trying to cheap out by building a 306 because i'd still be using quality parts. I just dont see spending a good bit more money for 20ish hp and 30ish ft/lbs. I mean, people on here run an h/c/i on their stock block for tens of thousands of miles with no issues, so i really dont need to dump a lotta cash into the shortblock because its simply unnessesary for such a build. I will be driving this car from NJ to Georgia 3 times a year for the next 3 years so i need something semi-reliable, and pretty streetable. I know its all in the tune, and i plan on a dyno tune for sure.

I think this thread is a learning tool for many guys on here, because i know im not the only one thats ever been in this situation, so put as much info as you can in here for me, and others will benefit as well.

 

[BlackVert]

with a 302/306, you can reuse your crank and rods. that is the big savings going that route. 306 rebuild kits with forged pistons cost about $520 shipped from summit.

have you thought about a 306 shortblock with a ported tmoss lower, afr 165s, a stock cam, a 1.8L kenne-bell blower, and a meth injection kit? killer street torque and great driveability.

 

[final5-0]

You are wise to think ahead and plan accordingly Michael

To me, the most important thing I see in your whole story is ......
this Stang is your ONLY car.

If it is a weekend toy only ........ you don't care about
gas milage
steep gears
radical cam lope
etc, etc, etc

No matter if you start with a low mileage, untouched oem motored Stang
or
If you plan to do a 306, 331, or 347 ................
You pick parts that give optimum performance for your choice in size

I went back and read your first post again and saw you want mid 12's so you really are not asking for a lot

Heck ... my little oem blocked based combo will produce that so a stroker is not a must have for your goals.

Trying to help you relate just a bit here

I really don't know what to tell you except

A h/c/i combo like mine would be similar to a B&B'ed 306.
I'd expect you could pull a bit more from it as we talked about above.

If you did go 347, some parts would be quite different like heads, intake, etc.
The price won't always be more expensive for ALL the parts.

I looked at your sig closely Michael.
You got a lot of mods
but
no motor mods
so
you're not committed with a heavy investment in 302 ci size motor parts.

I saw you have concerns about drivability and reliability.

Don't let anybody kid you

300 rwhp from a 302-306
or
350 rwhp from a 331-347

Neither is gonna be as practical of a daily driver as a stocker
or
something milder with oem GT40 stuff like the Cobra.

I guess I'm trying to say all my input in this thread has been about a Street Combo that is close to the limit of drivability.

While my examples here would be quite street worthy
and you could even take it on a trip ............
its gonna be pretty thirsty for that good 93 grade gas

It's cam lope is gonna draw a good bit of attention
be that a good or bad thing ... only you can decide

I don't know Michael, maybe you should wait on the stroker when you can have a beater to serve your daily duties.

If you go with a bunch of 302-306 parts now
and
later on want to go 347 ............
you have then got a bunch of too small parts

You got some deciding to do my friend

Trying to tell you how it is but I some how feel I'm not doin so hot

Grady

 

[stprorolla49]

You are wise to think ahead and plan accordingly Michael

To me, the most important thing I see in your whole story is ......
this Stang is your ONLY car.

If it is a weekend toy only ........ you don't care about
gas milage
steep gears
radical cam lope
etc, etc, etc

No matter if you start with a low mileage, untouched oem motored Stang
or
If you plan to do a 306, 331, or 347 ................
You pick parts that give optimum performance for your choice in size

I went back and read your first post again and saw you want mid 12's so you really are not asking for a lot

Heck ... my little oem blocked based combo will produce that so a stroker is not a must have for your goals.

Trying to help you relate just a bit here

I really don't know what to tell you except

A h/c/i combo like mine would be similar to a B&B'ed 306.
I'd expect you could pull a bit more from it as we talked about above.

If you did go 347, some parts would be quite different like heads, intake, etc.
The price won't always be more expensive for ALL the parts.

I looked at your sig closely Michael.
You got a lot of mods
but
no motor mods
so
you're not committed with a heavy investment in 302 ci size motor parts.

I saw you have concerns about drivability and reliability.

Don't let anybody kid you

300 rwhp from a 302-306
or
350 rwhp from a 331-347

Neither is gonna be as practical of a daily driver as a stocker
or
something milder with oem GT40 stuff like the Cobra.

I guess I'm trying to say all my input in this thread has been about a Street Combo that is close to the limit of drivability.

While my examples here would be quite street worthy
and you could even take it on a trip ............
its gonna be pretty thirsty for that good 93 grade gas

It's cam lope is gonna draw a good bit of attention
be that a good or bad thing ... only you can decide

I don't know Michael, maybe you should wait on the stroker when you can have a beater to serve your daily duties.

If you go with a bunch of 302-306 parts now
and
later on want to go 347 ............
you have then got a bunch of too small parts

You got some deciding to do my friend

Trying to tell you how it is but I some how feel I'm not doin so hot

Grady

Haha, despite what you may think, you make a lot of sense. To be honest, i want something with some balls that i can run at the track, but nothing radial. It is my daily driver, and to be honest, i dont really want a beater because if i had one, i wouldnt drive the stang as much... and what fun is that?!? The only thing is i cant drive it in the snow, but im at school during the winter anyway and its Savannah, GA, so theres no snow Basically, a year or 2 after i graduate, im either gonna keep this car and build a huge motor and use it as a track car/weekend toy and get a daily driver, or im gonna sell it to my youngest bro (hes 10 and knows more about mustangs than some of the guys on here ), and get a newer mustang...like...say a terminator I know what your saying about staying small and always wanting more power, but honestly i wont really need it. I just want something quicker that i can be more competative at the track with, because, not to toot my own horn at all, but im pretty damn consistant. Last time i went to the track, i went twice in one week, right before i left for school. I made 8 passes and they were 14.49, 14.49, 14.50, 14.49, 14.48, 14.52, 14.80 (let off at 1000'), and 14.49. I feel like with a bit more power, and some seat time, i can be pretty good at the track, because i LOVE bracket racing with my dad, and i never get sick of it.

Do you have any more pluses to a 306 based motor? And a really good combo? It will be a lot more cost friendly, and in the end, probably a better choice. Thanks!

 

[Killercanary]

To add one thing to Grady's post above, although it may be a little bit more expensive to do the 331/347, I feel you can get better driveability out of it as you would a 306 at the same power levels. What I mean by this is that you can go less agressive with the bigger cubes in terms of cam and gears and still get the performance that a 306 with a wild cam and steep gears would give you just due to the added cubes.

I'm trying to push my dad in this direction right now. He wants to drive his car more on the street now. His combo isn't too wild for a street driven car, but I know that with changing nothing else other than the cubes he would enjoy the car a lot more as it would "tame" the driveability down, but at the same time wake up the power. His 302 (standard bore setup) makes 347rwhp, but it bucks below 2000rpms and he runs 4.30's. I'm willing to bet that with a 347 it will not buck anywhere near as much as it does now and that he'd be able to step down the gear ratio a bit which could make it a better street cruiser. I wouldn't be surprised to see it put down 380+rwhp too.

 

[stprorolla49]

To add one thing to Grady's post above, although it may be a little bit more expensive to do the 331/347, I feel you can get better driveability out of it as you would a 306 at the same power levels. What I mean by this is that you can go less agressive with the bigger cubes in terms of cam and gears and still get the performance that a 306 with a wild cam and steep gears would give you just due to the added cubes.

I'm trying to push my dad in this direction right now. He wants to drive his car more on the street now. His combo isn't too wild for a street driven car, but I know that with changing nothing else other than the cubes he would enjoy the car a lot more as it would "tame" the driveability down, but at the same time wake up the power. His 302 (standard bore setup) makes 347rwhp, but it bucks below 2000rpms and he runs 4.30's. I'm willing to bet that with a 347 it will not buck anywhere near as much as it does now and that he'd be able to step down the gear ratio a bit which could make it a better street cruiser. I wouldn't be surprised to see it put down 380+rwhp too.

This is true, but i dont plan on a wild cam and lots of compression on the 306 anyway. I know with like 12-13 to 1 compression, a huge cam, and some huge heads, i could make 400rwhp or more with a 306 but thats not what i want. I want something along the lines of what you had on your stock bottom end, but with a 306 shortblock instead. Am i wrong that it will cost a good bit less money to rebuild the stock shortbloc than to build a 347?

 

[donkey_punch]

if your not going to storke the bottom end, and you current one does leak or smoke. then why even spend the time and money to tear into it.

just spend the funds on a H/C/I with supporting mods like maf, TB , injectors etc..
and call it a day.

just MHO