351 swap, engine and boost questions

Pokageek said:

:Word: I am having all kinds of little "stuff" I need to get it right. Firts, getting out the rattles and squeaks, pulleys out of alignment, suspension not anywhere near up to par and needs welding AND expensive upgrades, new tires that will bite, parts just up and fail in the changeover, rad aint up to snuff need larger one...must fab the fan b/c it doesn't fit right,..engine hits hood $500 new hood and then paint..need to downgrade the gears for a street car or spins like hell..blah..blah..blah.. not trying to discourage but there's a lot to it.

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Exactly there are so many little things that people don't realize!

TurboSnake95 said:

Also when you start this build, I hope you have another car for a daily driver ^^ it will be a life saver.







I would like to see my car too

I'm currently in Korea for a few month's but will be back in middle of June. When I get back I'll be upgrading my 72lb injectors up to 160lb'ers and also stepping up my Turbo from a T-76 Q-trim to a PT88, and also some other misc. things. Right now I'm pushing 700rwhp thru the C-4 as stated above, but am looking for 950-1000 with the PT88, shouldn't be a problem, might have to tighten the PTC torque converter up though.

Were at in WA are you? close to I-5 corridor?

- Will

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I'm up North in Arlington. I talked to you on Stangnet last summer and was hoping you would make the roundup in Bellevue but I never saw your car there.

Sorry for the thread highjack, please forgive us. I can remove this if you would like?

S351Saleen77 said:

I'm up North in Arlington. I talked to you on Stangnet last summer and was hoping you would make the roundup in Bellevue but I never saw your car there.

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Ya, about that, I really wanted to be at the Bellevue roundup, but I was out enjoying the car one night with some friends, and ah...........well I'll let the pictures do the explaining

This was at 2am in the morning:



The aftermath when I droped the tranny:






Keep in mind, this was a SCAT SFI racing flex plate, I have since purchased a JW "The wheel" Flex plate, and never looked back

-Will

Will,
WOW!! I always wondered about some of the flexplates, they just didn't look strong enought to me to hold this kind of hp and torque. Glad you found a good one! Now I see why you were not there.

Viridonplague,
I had a stock ford Trac lock which I think is what you have ? (03 Cobra or are they different?) and when I took the rear cover off I had teeth missing from 2 of the spider gears and EVERY tooth on all 4 were cracked. It was a time bomb ready to let go. My ring and pinion and axle's were O.K. So I put a Torsen T2-R in and so far so good. At these power levels I would keep a close eye on the Ford design. This is why guys switch to a 9" and drag racers use spools because the 8.8 will start to break at these levels, especially if you use slicks.

Edit: I need to say I had a 28spline unit I'm not sure how much stronger these parts are or if they are in a 31 spline unit? I put in the 31 spline Torsen T2-R because it is a high bias diff. It puts 2 times the amount of power to the outside wheel before it will spin the inside wheel in a corner over the Ford or other non high bias diff's, and does not have spider gears. Traction is a huge issue!!

I'm running FMS 03-04 Cobra 31 spline Diff. w/ carbonfiber clutches, and 31 Spline Superior axles, No problems what so ever, and Im launching off of 4-6 PSI at the line. Let alone all the street fun I have

-Will

This is what I believe to be a GREAT THREAD

It gives everyone a chance to see what is involved in a combo that is beyond
bolting something on a stock or OEM block.

I know most of our members don't have any or much experience beyond
bolt-ons.

Heck Fire ... A basic aftermarket h/c/i combo such as the TFS kit ........
It has sent some running & crying into the weeds
Never the more to be seen again

They just weren't prepared for supporting mods needed
You know things along the lines of .......
cooling system
fuel system
tune
etc

Then ... When you consider the possibilities of .........

Blown Combos
Turbo Combos
Stroker 5.0 Combos
Windsor Combos
and the list of more involved combos can go on and on

It seems these days

So many think they can do ANYTHING they want or feel they need to do in
order to make 400 or better to the wheels with not any REAL idea about
what all might happen.

You see it all the time .......

You get down into the thread a good bit ...........
and then
They say they only got ... ONE car

This thread is gonna be of so much help for those peeps who have not
done this kinda thing before

That is the great thing about this site and the members here

For the most part ...
peeps are honest about what did or did not work
and
if they would do it again or not

Everybody ... I encourage you
Pay close attention to those speaking here that have ... done it :Word:

Grady

TurboSnake95 said:

I'm running FMS 03-04 Cobra 31 spline Diff. w/ carbonfiber clutches, and 31 Spline Superior axles, No problems what so ever, and Im launching off of 4-6 PSI at the line. Let alone all the street fun I have

-Will

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I had no idea that I had a problem with mine until I took the cover off and had the axle's out and was REALLY looking close. No noises , nothing. I would check it every year if it was me....But Like I was saying before I have no idea if a 31 spline unit is stronger in this area? I know Ford never designed them for these power levels.

I looked in the new 2008 Ford Racing catalog and see they sell Auburn units and Auburn Pros which say they handle 50% more torque than standard Auburns.

I thought standard Auburns were more heavy duty than Ford units, thats why they sell them at Ford Racing? To get something stronger, otherwise why sell it if your own design is stronger? I remember reading something not good about the Auburns when used in road racing at the Bondurant school, they have cones instead of clutches and once they screw up its bad I guess. Thats why I wanted something without clutches to wear out.

Anyway I just thought at these power levels that the stock Ford 31 spline unit would start to have problems. I know the carbon fiber clutches will take more but thats not where I had my problems. I'm glad yours is holding up o.k.!!

new plan:

sell the stang.
buy a yugo
save the 30 grand
buy a used c5 vette or viper

Well since you are listing parts, here is a short list of my stuff to help give you an idea:

Engine Specs:

1. Dart 302 8.2 deck block stroked to 331ci
2. AFR 185 aluminum heads (2.02/1.6) Port match to intake and stronger valve springs
3. JE forged 1.175 pistons, 14.2cc dish (8.9:1 compression)
4. Scat 4340 5.400” H Beam forged rods
5. Scat 4340 3.25” forged crank
6. Custom grind Comp Cam for Turbocharged application
230/232@0.050, 0.544/0.544, 114 LSA
7. ARP studs and bolts throughout
8. Clevite 77 bearings
9. Total seal classic race fittings
10. Cometic Head gaskets
11. Crank Balanced and Blue printed to 28oz
12. Trickflow R intake system w/ 1” phenolic spacer
13. 70mm BBK TB
14. 72lb fuel Injectors flow matched Delphi (low impedance)
15. 1.7 stud mounted Pro Magnum roller rockers
16. BBK under drive pulleys
17. 160* Thermostat
18. Hardened Comp Cam push rods
19. New Comp cam lifters
20. Power bond SFI certified race balancer @ 28oz
21. JW "The wheel" SFI aluminum flex plate @ 28oz
22. 7qt Canton rear sump Drag oil pan

This is the other supporting stuff currently installed

1. 1994/95 custom T-76 Q trim .96 AR Turbo TTI Race kit (Intercooled)
2. Aeromotive 1000 competition Fuel system (complete) - upgraded pump to the Eliminator Fuel Pump, P/N 11104:
3. F.A.S.T computer system with 3 bar boost MAP and closed loop wideband O2
4. Built C-4
5. PTC 9.5” Torque converter (custom)
6. MSD 6AL
7. MSD blaster coil
8. MSD 2 Step
9. 31 Spline Axles - Superior
10. 31 Spine Diff. - FMS 03-04 Cobra vers. w/ carbonfiber clutches
11. 3.27 gears
12. Strange cromoly drive shaft
13. Maximum Motor sports Full length sub frame connectors
14. Maximum Motor sports 6 point roll bar w/ swing outs
15. 5 Point Racing harness X2
16. Corbeau Racing seats
17. Eibach Pro-Kit Springs
18. Aluminum Back Seat Delete (Custom made)
19. Drive shaft safety loop
20. RCI Transmission blanket
21. B&M Pro Ratchet shifter
22. B&M Super Cooler
23. Urethane Engine and Transmission mounts


Originaly I was running Probe Forged pistons, but during a tuning session we pushed the rings thru the top of the piston. We found out later that the meat on top of the piston was not thick enough for what we were doing, and thats why the rings pushed thru the top. The pistons looked like someone took a hammer and pryed the edges up Anyways, went with JE forged pistons this time and haven't had an issue.


When the build was completed, we originaly tuned it at 600rwhp, after a few weeks I located another shop who specialized in tuning a F.A.S.T system, and they tuned it to it's current numbers of 700rwhp.



Total Cost: First born child and some change.

-Will

I have no drivability issues, last time I went to the track I drove from Spanaway, WA. to Woodburn OR. about 175 miles to the track, ran 10.3 and drove it back home another 175 miles +/-.

Normal driving in my car is like driving a NA car, it's when you floor it and put a load on the Turbo that wakes it up. If I don't floor it I get about 18-20 mpg +/- about what a stock mustang gets. But when I floor it and the 72lb injectors open up full flow I get about 9 mpg


As for what is the better combo, it's all really up to you, what you want, and how you want to get there. Any forced induction setup will net you big power gains you want, you just need to decide what power you want, how much money you have to spend, what power adder you will be using, and then go from there to decide how much air flow you will need and all the supporting mods. All comes down to personal prefrence really. The more air you can push thru a engine the more power you will make, just make sure you have enough fuel and spark to compensate for the extra air


-Will

O sheesh...all I can say is that I am glad I stopped where I did. 450rwhp is fine for me @ $20,000 less...at least at this point in my finances.

What I’m trying to give you in this post are some things to think about to help you decide what decision to make. I know how hard it is and this is a huge choice to make.

If I remember right a 302 weighs 460lbs and a 351 weighs 525 about 65lbs difference. Aftermarket blocks weigh more because they are beefier so the difference between a production 351 block and a aftermarket 302 block is even less, maybe 40lbs. You can make 600rwhp with a production 351 block which you can get cheap. I wouldn’t do it with a production 302 block. It’s not like you put one in your car and it handles terrible. Move the battery if your worried about it, and if you’re a drag racer don’t super size the fry’s!!

For someone on a budget but want’s 600rwhp use a stock 351 block add a girdle get good machine work use main and head studs buy some good flowing heads and drive it like that until you can afford the supercharger. Even with a big cam, heads & intake it will make WAY more bottom end than your stock motor and way more up top. If its street driven it will feel much stronger than a smaller motor. You can make 500hp at the motor no problem and have tons more torque.
Or like you were saying that it might take you a few years before you add boost so now you have a lot more power for the next few years. A lot of guys on here have made the big cube swap, pull up to one of them with your 302 based motor and all you will see is their taillights. If it was me spending almost the same amount of money (unless you used the stock 351 block which would be a lot cheaper), I would want the power now for the next 2 years. It would drive me crazy….but that’s me.

You are talking about an aluminum 302 block having a weight advantage over a 351…I don’t think anyone here has a aluminum block?…do you have any idea how much a 302 aluminum block costs, around $5K. Same as buying an aluminum 351 block. Around 2k for an aftermarket iron block. Aftermarket blocks pretty much cost the same within a few hundred, 302 based or 351 based. I don’t think that the weight will be that big of an issue unless you are competitively road racing it. A TT and all the plumbing and intercooler will add up in weight also.

If your buying a block and all the internals it doesn’t cost much more for the 351 based stroker parts vs 302 based. And when your buying a aftermarket oil pan, headers, dist, intake, cam, rockers, etc,etc they all cost the same weather they are for a 302 or 351. With a 408 or larger you spend more on heads because you should buy the higher flowing ones and they cost more. People who have mild 302 combos already have an intake, heads and headers that they can’t reuse so they have to buy things twice. That’s expensive.

On reliability well that’s a matter of opinion like everything. All I can say is I’m making this power at relatively low boost. You decide. Drivability depends on how well it’s tuned. Big motors have great drivability on the street. Torque is what makes a great street motor, and what do you get when you add more cubes? Torque.

These new Mustangs with 281’s making all the power with Kenne Bells are running 20+ lbs of boost!! Put 20+ lbs on a 408 and see what it’ll make!! I’m not putting as much “stress” in my opinion to make the same power a smaller motor would. When they supercharge they have to run a positive displacement instead of a centrifugal if they want bottom end torque because they don’t have the cubic inches. Also the boost comes on full at low rpm like 2k which is way harder on a motor than adding boost as the rpm climbs. With big cubes you don’t need it that low. Again more cubes makes a difference in how you can approach your power goal.

If you get the fuel system you were talking about it would support it no problem, so what would the problem be? It doesn’t matter that it takes power to run the S/C if the system can handle it. I was just saying before that you need to have one that is capable. I also don’t think it’s going to take 150hp to run a centrifugal blower.

Like Will was saying it’s all about personal preference. Big cube small blocks are awesome and that is what I like, but if everyone had the same thing it would be boring!! Either way after you give them boost they will both make the 600 rwhp that you first said you wanted. Do what makes you happy, you’re the one who has to live with the decision.