302......306.....331 ????

[ras50gt]

Need help and opinions....Im looking to either rebuild my stock 302 or to build an engine on the side. I want to stay within a reasonable budget. It's also my daily driver, so i dont need something crazy. Here are some of the ideas i had, someone let me know what they think is the way to go. My car currently has about 110k miles. Opinions are helpful as well as where to get a block or parts, etc. Thanks!!!!

1. Get my stock 302 rebuilt, add heads, cam, etc, supercharger. Only thing is, how does the price to get a stock rebuild compare to going 306. Also, how long the shop will have my car for, which is a big factor. I go to school full time and almost work 40 hours a week. I need my car!

2. Find a 302 block, do the 306 route. I can probably find a used 302 block for pretty cheap. How much would the rest cost(machine work) and what exactly do i need to buy from there as far as pistons,etc? If you can give me price ranges, even part numbers that would be great. I would then add a set of good heads, etc.

3. 302 sportsman block for $900 new. It says its finished and ready to use with a 4.000 bore, what does that mean? What would my options be from there. Is the sportsman block worth the extra money? Then should i do 306? 331? About how much in parts would i be looking at after that? I dont think i want to go to a 347. I also would like to possibly do a supercahrger in the future....always wanted one, so the reason why im considering a sportsman block, its stronger right? Should i be considering a DART block or 302R block?

4. Any ideas you guys have! Also, help me figure out the stoke and bore thing? Is this right..... 331=3.25" stroker crank, 4.030 bore? SO, the sportsman block in number 3(above) would need to be bored to 4.030??

Im leaning towards building a block on the side because i dont really need a rebuild right away. Some other mustang guys told me to just do the 306 route, buy another block and get the machine work done, get a good cam, then slap a supercahrger/some bolt-ons and be done. I also figure over the next few months i can save money for parts i want,etc and try to do it right the first time. Like i said though, its still my daily driver but i want more power. I still need to stay some what reliable and passing smog might become an issue too. Im not too sure about how much machine work costs so i need some insight on that as well.

 

[mustangsally93]

One word



331 dart short block 8.5:1 flat top pistions!


Well thats like six words. Talk to rick here he can help you the best.
The down side my my short block started at 4589 and went up.

 

[86bluecobra]

i would also go with a 331 stroker if those were my options. if you are going to have to do internals in your rebuild might aswell add more cubes.

 

[sunil6784]

306 is not a lot more expensive to do than a 302. When you machine the block, and you bore the cylinders .030 over, you get 306 ci. Most people go this route because they want to make sure that the cylinder is perfectly round, and no wear on the walls. Usually its like 15 bucks a hole to bore it.

I'm currently doing a 331. Its not a WHOLE lot more than a 302/306. It's like 500 more for the stroker kit. What does cost more, depending on how much power you want, is the heads, intake, cam, injectors, TB. It all adds up to feed the bigger motors.

 

[ras50gt]

Sunil6784: so with the 306, i would need to machine the block then get a stock rebuild kit. Basically it is pointless not to go to a 331 kit, i know the kits arent that much more than stock rebuilds.Do i go with forged? flattop? what kit did you get? Is there more machine work that needs to be done then? Cost? So if i went with the 331, i most likely will buy another block and build it on the side and buy parts as i save up the money. Should i just find a used bare block? buy a new bare block(i think summit has them for like $500) Go with that sportsman block for about $900? What did you do, what do you suggest considering my situation? Also, how streetable is a 331/heads/intake/etc with a supercharger? What heads would you suggest, could i use trickflow twisted wedge heads? When should i think about a transmission rebuild or upgrade? Thanks for your help! I cant wait to start working on my car. I have a bunch of parts just sitting in my garage waiting for me to install them.

 

[gt40_2003wes]

331

 

[sunil6784]

A 306 is nothing more than a 302 bored .030 over, giving you 306 ci. So since the standard bore on a 302 is 4.000 inches, when you bore it .030 over it becomes 4.030 (4.000 + .030 = 4.030). So all a 306 rebuild is the stock spec crank, with .030 pistons. People don't do a 306 to really pick up any cubic inches, more so because they are rebuilding the bottom end so why not clean up the bores.

I talked to my machine shop and asked him what he recommends as well. He said the number one thing that I needed to do was to get a plan. I've decided i'm going to keep this motor N/A (naturally aspirated, no nitrous, no supercharge etc.) I'll be able to run more compression this way, probably around 10.5:1. If you are sure you are going to add a supercharger down the road, then you are going to want to keep the compression down, probably towards 8.5:1 or 9:1, depending on how much boost. Do a search about that, not entirely sure.

Another thing you need to consider is if you are going to be supercharging it, how much power are you gonna be making. A stock block is generally good for 450 rwhp, plus or minus a few. If you plan on making more than that, then you are going to want to step up to a beefier block, like a Dart block, which is up near 2000 dollars. This is one of the reasons why I am not boosting my motor. I got a great deal on a new block, but it is a factory Ford 302. I can achieve my goal of 375 rwhp without the boost.

You've got a few options for the block. You can either get a used one, and get it cleaned up. (Bored, honed, tumbled). This usually runs around 300 - 400 dollars, plus the cost of the block. You are right at the price of a new block from summit this way.

You can make a 331 streetable or not-so-streetable. Its all in the combo. If you stay small, like AFR 165, an RPM intake, and a small cam, it will be quite streetable.

As for the Tranny, What do you have? An AOD ? T5? What year is the car?

Oh by the way, you can also get a stroker crankshaft, and get standard bore pistons. I think this comes out to like 325 or 326 cubic inches. That way, if you get a new block, you don't have to bore it/hone it/tumble it. That will save you some money.

There is no more machine work with a 331. Only if you go to a 347, you have to notch the block for the rod throws.

For my build, going all out, with AFR 185's, an intake(not sure which one yet) and a custom cam, I'm figuring around 4500 dollars. This is with a new block I picked up for 200 dollars, and getting it bored/honed/tumbled. I plan on keeping it streetable as well, but my car only comes out for about 8 months a year, (New England Weather) so I can step up a little bit since its not my daily driver.

This is the kit I will probably be getting, except I will be getting either the SRP or JE pistons instead of the Probe ones. They also have a complete Forged setup as well, for 400 dollars more. I'm debating between the two, and if I really want to spend the money for the forged stuff.

http://www.adperformance.com/index.php?main_page=product_info&cPath=71_161_164&products_id=351

 

[Modular2v]

331

 

[Modular2v]

A 306 is nothing more than a 302 bored .030 over, giving you 306 ci. So since the standard bore on a 302 is 4.000 inches, when you bore it .030 over it becomes 4.030 (4.000 + .030 = 4.030). So all a 306 rebuild is the stock spec crank, with .030 pistons. People don't do a 306 to really pick up any cubic inches, more so because they are rebuilding the bottom end so why not clean up the bores.

I talked to my machine shop and asked him what he recommends as well. He said the number one thing that I needed to do was to get a plan. I've decided i'm going to keep this motor N/A (naturally aspirated, no nitrous, no supercharge etc.) I'll be able to run more compression this way, probably around 10.5:1. If you are sure you are going to add a supercharger down the road, then you are going to want to keep the compression down, probably towards 8.5:1 or 9:1, depending on how much boost. Do a search about that, not entirely sure.

Another thing you need to consider is if you are going to be supercharging it, how much power are you gonna be making. A stock block is generally good for 450 rwhp, plus or minus a few. If you plan on making more than that, then you are going to want to step up to a beefier block, like a Dart block, which is up near 2000 dollars. This is one of the reasons why I am not boosting my motor. I got a great deal on a new block, but it is a factory Ford 302. I can achieve my goal of 375 rwhp without the boost.

You've got a few options for the block. You can either get a used one, and get it cleaned up. (Bored, honed, tumbled). This usually runs around 300 - 400 dollars, plus the cost of the block. You are right at the price of a new block from summit this way.

You can make a 331 streetable or not-so-streetable. Its all in the combo. If you stay small, like AFR 165, an RPM intake, and a small cam, it will be quite streetable.

As for the Tranny, What do you have? An AOD ? T5? What year is the car?

Oh by the way, you can also get a stroker crankshaft, and get standard bore pistons. I think this comes out to like 325 or 326 cubic inches. That way, if you get a new block, you don't have to bore it/hone it/tumble it. That will save you some money.

There is no more machine work with a 331. Only if you go to a 347, you have to notch the block for the rod throws.

For my build, going all out, with AFR 185's, an intake(not sure which one yet) and a custom cam, I'm figuring around 4500 dollars. This is with a new block I picked up for 200 dollars, and getting it bored/honed/tumbled. I plan on keeping it streetable as well, but my car only comes out for about 8 months a year, (New England Weather) so I can step up a little bit since its not my daily driver.

This is the kit I will probably be getting, except I will be getting either the SRP or JE pistons instead of the Probe ones. They also have a complete Forged setup as well, for 400 dollars more. I'm debating between the two, and if I really want to spend the money for the forged stuff.

http://www.adperformance.com/index.php?main_page=product_info&cPath=71_161_164&products_id=351

I had to notch my block for my 331 rod bolts to clear

 

[ras50gt]

sunil6784 I have a 93 GT, 5-speed. Maybe ill just need to rebuild it or should i consider a different tranny? I'd be happy with around 350-375rwhp. You said that after buying a block and gettting the machine work, i would be around the price of the summit one. So that isnt too bad of a deal then for a sportsman block? It says that its finished with a 4.000 bore, so i would still have to get some machine work done for a 331 correct? Do you think i should just find a old 302 and get that bored/honed/tumbled. I forgot where but i say a new bare block for 450. I will prob stay small because i want a fast streetable daily driver. Will the stroker have a harder time passing smog? Plus i have to stay within a budget, i started school so i had to cut work hours which means less money to buy parts. Ive been thinking about buying another cheapo car so that way i can work on my car more, but that would be a chunk of money that can go towards the engine, plus what happens when the beater goes dead. The other thing i mentioned was a supercharger, that would prob be way down the line, ive just always wanted one but thats when i was thinking about just simply rebuilding my 302. Thats another thing, would it be worth it to just get the sportsman block? Are they really that much stronger? So should i be thinking about going forged?? I just looked back at what you said about the 325 or 326, that might not be a bad idea with the summit block then, i could just say its a 331. What the diff in hp, i know that not easy to answe because of diff combos, etc. Its prob a few hp right? That would save like 3-400 bucks of machine work? I think i would go all the way to 331 at that point. Thanks for all your help sunil6784 !!!

 

[txstang84]

...There is no more machine work with a 331. Only if you go to a 347, you have to notch the block for the rod throws...

that's not entirely true...when I assembled my friends 331, we ended up having to notch the cylinders. I've heard the same claim before...technically, you could get away without notching the cylinders, but the miniscule amount of clearance (less than 1/4") prompted me to go ahead and grind out some small notches...no need to press my luck.

 

[DMAN302]

331 will want a set of better flowing heads, cam, intake, injectors, fuel pump, maf...plus all the other wallet draining items that go with a fresh motor. If your looking to make 350RW you going to spend some nice cash.

 

[sunil6784]

I had to notch my block for my 331 rod bolts to clear

Really...hmm...Which kit is that? Is that one you put together yourself with the Eagle rods and Scat crank? I definitley don't want to have to notch the block when I put mine together...

I've heard most 331 kits you don't have to notch the block, but with all 347 kits you do.

 

[sunil6784]

You can keep the stroker smog legal-just throw all the smog stuff back on. Also, make sure you get emissions legal heads. If you build it on the side, you can still keep your daily driver till teh very end, until you have to pull the motor out of your mustang. I have th same tranny you do, and I'm not going to worry about it until I blow it up, then I will upgrade it.

 

[Modular2v]

Really...hmm...Which kit is that? Is that one you put together yourself with the Eagle rods and Scat crank? I definitley don't want to have to notch the block when I put mine together...

I've heard most 331 kits you don't have to notch the block, but with all 347 kits you do.

yes...i assembled it myself and even dummied it all up and turned the motor over by hand on the engine stand and they hit.....it was just a small tap either....they HIT!

 

[Rick 91GT]

Really...hmm...Which kit is that? Is that one you put together yourself with the Eagle rods and Scat crank? I definitley don't want to have to notch the block when I put mine together...

I've heard most 331 kits you don't have to notch the block, but with all 347 kits you do.

I've notched every 331 or 347 I have built for customers.... I-beam or H-beam, cap screw or conventional bolt, Eagle, SCAT, RPM, etc.

 

[Sicarius428]

If you are on a budget, stick with a 306 because if you go 331 you need a lot of supporting mods to keep up which adds up quickly. 306 you can get by with the stock stuff and use your stock block. Not sure if you are going to hit hte 350hp mark though... For streetable 350+HP at the rear wheels you are gonna need forced induction or 331 stroker with a good H/I/C, MAF, TB, injectors...etc.
Kevin

 

[89white50]

You sound a lot like myself. I am a fulltime college kid, and my cars is my DD from april till august. I want power right around or above 375rwhp. So i bought myself a whole 88 5.0 motor off of ebay locally. I got to check it out top to bottom. And for 150 the motor was complete. So im tying to sell everything i dont need so theres more money for the build.
Anyways. i am building a 331, already bought the crank and rods are on the way. If you looking for these kind of #'s you do not need a Dart or sportsman block. Though itd be nice for growth if you ever want more. I am going with flat top porbes, High Port TFS heads, Comp Cams EX274HR, and unsure of the rest. I added up all the totals, after machining, all the parts, and putting the motor together and putting it into the car myself it should cost me right around $3,300.00 But i have rebuilt my current motor already and have great help so that parts easy.
So id say buy a spare stock block and go from there, machining it is going to run around 500 alone. and clearance it urself, thats saving me 200$.

 

[89white50]

oh and the summer after ill need a new trans cuz the t5 will be a time bomb with that kind of power. then ya need new clutch and might as well get a Al flywheel. so its never ending.

 

[304billet]

I would rebuild the 302 and do a 306 w/ SRP or Probe flat tops 9:1 comp, stock rods and crank. Add a set of AFR 185's or TFS TW 185 cnc'd heads from Summit, Comp cam XE282HR w/ a 114LC, port matched RPM ll, S-Trim blower and be done with it. Keep the rwhp below or at 500 and get it dialed in with a custom burned chip.

I wish I would have done this instead of building my old 347 stroker, been way more fun, more hp and cheaper.