Has anyone ever tried to build a high revving 302 TPI motor. It would be a destroked 350 with a 3.00 crank and 4.00 bore. I want to start making blueprints for this very unique motor setup, then build it during winter time when my car will be in storage. I would make it red line around 6900 rpm . Since the TPI has awesome low torque, the high end performance of the 302 would perfect the overall performance of the motor imo. I already have a blower (8+ psi of boost) that I would use for midrange power. What do you guys think, good project to start? I own a 5.0 camaro, it will still be a " 5.0 camaro" with this 302. The overall horsepower with the blower would probably be over 400.

 

Actually you'll find that it won't spin any higher than a TPI equipped 305.

 

What about with the help of forced induction then? I would port the manifold and the runners then switch over to 24 lb injectors.

 

With forced induction it'll behave about the same as a blown 305 as well. Slightly better NA cylinder filling due to the larger bore, but that's about it.

 

I would be using a newer 4 bolt main roller block. How could I make the tpi intake system flow better with out a blower? So if I would install a cam that has a power range up to 6700 rpm, would it shift around 6000 rpm because of the lack of air flow from the restrictive tpi intake?

Found this from an older thread:
1.High Revving. ---- In the racing world, where engines are going to sustain high RPM's for extended periods, it is possible to see an advantage to a 327 engine. It does have the advantage of the shorter stroke. This is also in a situation where both engines are built to exacting and equal tolerances. However, in a street engine, where the max RPM’s are still going to be under 8k, the stroke really is irrelevant.

What dictates the ability to “rev” easily lies more in the valvetrain than in the stroke. The stroke may help in sustained high RPM situations, to an extent. The ability to reach those RPM's lies in the engines ability to effectively open and close the valves and move enough air through the engine. Basically an internal combustion engine is no more than an air pump. If the ability to flow the air is there, the ability to reach those RPMs is there also.

2. More Durable at High RPMs (ability to safely rev that high on regular basis) --- This is true and false at the same time. The shorter stroke does allow the engine to sustain the higher RPM in a “more safe” manner. However, contrary to common belief this will not be done on a stock 327 shortblock. The 327 does not have any magical composition that other SBC engines lack. Stock rod bolts aren't going to take it. The bearing tolerances have to be exact. Everything must be right. In essence, if you were to invest this same amount of time, money, and effort into a 350, you would yield the same results.

 

Popular choices are to use a larger throttle body, port the intake, port or use aftermarket runners, or use something other than TPI.

 

If you are looking to spin that thing anywhere close to 7,000 rpm's, you will need a Mini-ram or a single plane manifold IMO.

 

I would have this guy port my current intake. I can't find his website. http://cgi.ebay.com/ebaymotors/TPI-C...spagenameZWDVW

 

Article on destroked 350 (302)
http://www.hotrod.com/techarticles/3...ild/index.html

 

What are we supposed to be seeing in that article?

 

The engine plans in that article are almost all similar to my project I am planning, and they are using a supercharger too. I am also backing up that the motor is very efficient. TPI intake for good low end, supercharger for midrange, then good top end horsepower. I couldn't find the end results, probably because the follow up article is not out yet.

 

It doesn't work quite like that.

An engine makes power by burning air. The determining factor for how much power an engine will make is how much air you can move into it in a given amount of time. The same heads will make the same power on a 302 as they will on a 350, they'll just do so at a higher RPM. The 302 takes in less air on each revolution, so it ends up needing to turn more revolutions per minute to draw in the same amount of air to make the same amount of power through the same heads and intake as a larger engine.

TPI makes low-end torque by using a tuned-runner effect to increase cylinder filling and volumetric efficiency, at the cost of restricting air flow at the top end. The restriction in the top end can't really be overcome. You can add a supercharger, but boost will negate the tuned-runner effect. It'll help force more air through the top-end restruction, but it still won't flow as well as the same blower would on a less restrictive intake design. That may or may not matter though, because to an extent you can just turn up the boost.

 

If you want to make high end horsepower, throw the tpi in the trash can, don't waste money on aftermarket tpi parts....
Use a miniram, stealthram or converted single plane.

 

I'll be looking into the holley stealth ram or a converted lt1 intake.

 

I'd also look into using a 3.75 in stroke crank as opposed to a 3.00. There's no sense in spending more money only to go slower.

 

I would be borrowing the crank and the rods from a 1992-1996 Junkyard L99. Then I would be able to use forged flat top 350 pistons instead of custom grinded ones. So costs would be the same or cheaper than building a 350. With the 3.00 crank I would be getting much better gas mileage than with the 3.75 crank. I want an interesting exhaust tone and high revving capabilities such as a red line of 6900. The cast L99 crank and rods could handle up to 500 hp where as I will probably be a little above 400 hp. I am not going for a drag racing camaro, but for pro touring street car. I know most of you recommend a 350, but when I go against one of these 4.6/5.0 mutangs in the future on a road course, I want to beat them with a 302ci motor to be fair.

 

High-revving capabilities don't come from the stroke. You can have a red line of 6900 on an engine of any displacement.

 

Your not gonna get much better mileage with a 302, especially if you run a big enough cam to make peak power @ 6500 + rpm's. I'd be a little leary of spinning a stock cast crank 6500rpm's anyway.

 

Change intakes.

You're wasting your time trying to high-rev a TPI setup. They just aren't built for it, you'll end up more frustrated than pleased with your results.

 

The original 302 cranks on the 67-69 trans am series camaros used cast cranks that revved 8000+ rpms. The newer "baby" LT1 cranks should be stronger. As for induction I would probably switch over to the HSR intake with whatever engine I go with.

 

dont worry original poster...
i see the light.

my plan is to sell my current drivetrain which consists of a 355 and 700r4,
buy an aluminum 4" block, mate that to a 3" crank and try and make it run with 12:1 compression.

then i would mate that to a t56 and take it out for fun.


although 6900 is pretty low.

the original chevy 302 engines were capable of over 10,000 in bursts on the dyno.

i wouldnt stop at a short stroke though.
valvetrain mods would be crucial in making it live.


meh.

one day, i will win the lottery and it can all come together.
hopefully.

until then, i will "live" with a 400hp 350 that is boring and only revs to 4500 rpms before it looses oomph.

 

A stock 400 is also capable of over 10,000 in bursts on a dyno.

 

People sure do get stuck on the myth that there are magical engine combinations or that small cubes rev more.
Next time you get waxed by an LS1, go check out the specs on that engine. You might find while you're looking that all the power that blew your doors off came from really good factory heads and intake.

 

 

If you notice, the majority of this comes from people who have never been to the track before. People who get to the track and hang out on sites where people ACTUALLY go fast tend to know what engine combos work and what is just BS.

This site is filled with big ideas that are proven to be false or just don't work. Too many stock 305 TPIs with ported heads on this site.

 

That and dad's uncle's 69 DZ 302 that would rev to the moon and beat everything on the road. If I had a penny for every 60's racing story and myth I'd retire.

 

the 302 was great for the trans am races, thats all shitty drag motor i hate it when people say otherwise....i have an awesome "muscle car" book around here somewhere with a great quote about the 302 camaro i need to find

 

found it here it is i love this.......(excerpt from a review about the 1969 Chevrolet Camaro Z-28 302 Cross Ram) "The good news was that the car had greater flexibility near the top of each gear and a higher top speed; the bad news was that freight trains could accelerate from a stand still faster...and perhaps quieter."

 

I scrapped the idea because I don't want to run high rear end gears, or switch out to a manual transmission. I am probably just going to rebuild my 305 next year unless I find a 350 core locally, then add on a custom large single turbo sts style system. I am going to be selling the supercharger I have soon. The 302 build is a cool idea, but lacks low end. I've talked with people who have built the 302 for their 3rd gens, and most say they rather of built the 350 instead.The 350 has more low end and can be made to rev high.

 

The 302 was used in Trans Am because that was a limitation imposed by the rules. Had zip to do with the engine's abilities.

 

well yeah i know that but it was designed to work well in that situation. if they could have ran a purpose built 350 im pretty sure they would have done so. i know they didnt just say hmm a 302 would be the best engine for these races....no they said hmm we have a 305cid limit so lets build this motor and design it to perform well in this type of race. thats the point i want to get across. the 302 was designed soley for the trans am races. the only reason it was sold to consumers was that it was a stipulation in the race series rules. so when people want to build 302s for their daily driver, drag car, street strip car, or anything besides road racing i think its kinds dumb. and i just love that quote...

 

If you check the specs on the 60's 302, the cam was very radical for that engine to run like it did, and as stated there is no magic just a whopping big cam in a little engine.

The torque band of any engine is 5000 rpm so when you turn to 10,000 where do you think it comes up on the cam at. I believe that the idle rises also. Ever drive a car that idles at 3500 rpm, think Nascar. Go take a ride at $100 a lap. you might learn something.

 

Is it?

 

SBC