has anyone else ever thought of destroking a 350 with a 3 inch 4.3L LT1 crank to get 302 cu. in.? Why, well with long runner TPI system it would make great torque for a small motor but I think think with aftermarket runners and base it would still run up top. Perhaps vortecs a sdpc base and a 5sp. 4.10's? All of the sudden single 3 inch exhaust dosen't seem so small. Same for the dual 48mm. throttle body, same for the 22lb injectors. I already made the dive into heads that are too big for a 302 and a stealth ram. But if I could do it again, I'd show those mustang boys that chevy's can run with only 5 liters too. I hate the ***** excuse, well If my mustang had 350 cubic inches. Sorry to ramble on, please let me know what you guy's think.

 

I do not know if the 4.3 lt1 crank will work, but you could find a destroked sc chevy gen 1 crank. Try it. you will have something not to many other people would have. and since you are thinking of rpm's I love the idea of 4.11's in a third gen. A stealth ram, mini ram, or lingenfelter would be the way to go. What kind f heads do you have they will probably still work fine. Sounds like your a doer and not a talker, I like that. I haven't talked yet on this ste about doing something , but in three weeks the car gets garaged for the winter and I 'll be rebuilding. good luck. don't let people start bickering about this post there are many that will.

 

302 cid v8 will want to rev really high, tpi won't. Big struggle there.

 

What do you mean by reving high I have heard and seen tpi's turn 7000-7500 rpm's after modyfing.and a engine that will want to turn high rpm's will help achieve high rpm's. Ignition systems help a lot in this department.

 

I don't know about 7,000 rpm's but I was only thinking around 6K. According to my calculations a 350 cubic inch engine needs around 526cfm at 5200 rpm. Most would agree that 5200 rpm is attainable quite easily with aftermarket induction parts retaining the long tube runners. On the other hand a 302 cubic inch engine needs 524cfm at 6,000 rpm. So in theory the airflow would be there to support 6,000 rpm and we all know the long runners promote great low end torque.

 

What kind of heads did you buy? I think that a HSR would compliment a hi revving 302. If your heads are 180-190cc and you match it with a good cam profile and a HSR it should run great. Remember back in the day they used the same heads on the 302's and the 350's.

 

So you want to build an EFI motor and destroke it, just to give Brand F a chance?

There's some flawed reasoning above in this thread. A LTR setup that will provide more lowend grunt to the smaller CI engine, won't allow enough air at the "higher revving" RPM range that the same very motor needs to spin to make the HP of a larger engine, so in effect you lose either way.

 

The more I think about this, if an engine is an airpump, and it is. Then all you would accomplish by consuming the same amount of air with a 302 @ 6,000 rpm is making the same horsepower a 350 makes @ 5200 rpm with less torque at lower engine speeds and a greater chance of parts failure. You wouldn't think that's much concern to me since I spin my 350 to 6,600 rpm. with the stock 190,000 crank. Oh yeah, I have pro topline 200cc. heads.

 

Remember the old 377 cubic inchers? Destroked 400? The cost of the custom crank alone would make the project not worth it, IMO, when you can just hopup a regular ol 305.

 

BTW z282slo, is Bellwood right by Altoona?

 

its the size and length of the TPI runners that strangle the engine at high RPM.. not to mention the 48mm throttle body.. you would need a 52mm or greater..

take a trip over to the engine swap board.. and you'll find a world of info on the 302..

from what i have searched out.. is that the DZ302... loves a single plane style intake for the high rev... do your own searches and see what you come up with..

its a great engine if you are racing and need to stay in the high RPMs but on the street.. its not really the best.

 

No, and no. You're looking at this the wrong way -- air flow is NOT the limiting factor here, it is the design principle of a tuned intake runner tract. Displacement does not affect the TPI's maximum rpm range as much as the fact that the TPI runners are tuned to reach resonance and "ram" air into the cylinders in the ~4000 rpm range -- you can't change this fact much, even with aftermarket base and runners. Someone did a calculation a while back to show how a 305 and 350 running TPI had the capacity to make peak hp at nearly the same RPMS. I have a 1967 327 with an Isky 280 HL hydraulic cam, small journal block, that I converted to TPI a while back. It strangled the motor something major -- I shift at 6500 rpms, much like what your 302 is going to want to do, and the TPI is done under 5000 (even on a small motor, doesn't matter). I got a Holley Stealth Ram and now rev to 7K easy, usually shifting again at 6500 for best et's. A TPI would be the worst thing you could do to a high revving motor -- using your Stealth Ram on the 302, if you had to run a 302, would be the way to go. Although it would be an awful waste of money to make so little displacement. Then again I could be running a 400 sbc with my HSR and be making a lot more hp than I am right now anyway.

 

Didn't anyone catch he stated:



Even so I would not drop it in a heavy car like a 3rd gen, stick in a something light.

 

You just said all the reasons why you would NOT want to do this. Same power but requires higher RPMs (stuff wears quicker and breaks more often) but with less low-end torque. Stick with something bigger.

 

i built a de-storked 350 for my old 84 firebird th350 3.23 gear holley 4 barlle it ran strong on top end but made no torque ran a 15.5

 

Whoever turns a TPI to 7000 rpm is an idiot.

 

my new 350 tpi goes to 6500 like cake

 

..and exactly how much power do you make? None.