All things being equal like CAM, heads etc. Sure you would need different crank, pistons for the 383 but that aside if you have the same parts on the 350 and on the 383 how much of a difference is there to be gained going the 383 route in HP and TQ?

No need to get into detail just an estimate on figures is fine. I am going to search the threads for a good 383 combo running TPI and see if it is worth the extra $$$ instead of the 350.

But he main question how much of a difference will it make stroking it.

 

there won't be many good combos running TPI, not stock TPI anyway. it's a very restrictive induction system. you can think of it in terms oh HP per cuibic inch, there is whatever amount more potential in the 383 than the 350 simply because of the larger displacement.

 

Yes, as ede said a 383 will have more overall potential than a 350. However, running a factory TPI on a 383 will be like running a race on crutches. Factory TPI chokes an engine by 5000 RPM. It would choke off a 383 even sooner.

The 383 is a torque monster, at least moreso than a 350 as the 383 allows greater leverage on the crank due to the increased stroke distance.

 

A 383 won't have a big enough advantage over a 350 with a stock TPI to make it worth while.
If you want more power, first get rid of the long, small runner TPI and get a HSR or TPIS mini ram or a LT1 intake conversion and improve or replace the cylinder heads.

 

So even with a modded a ported plenum and larger diameter runners it is still no good for a 383?

I know TPI has it advantegous in Low down torque and thought that it would suit the 383. I would not plan on running over 6k RPM anyway maybe 5.5K

 

Ive been thinking about this myself and I think the only tpi to run is the superram. Everything else tpi just seems to rob the motor of power.

 

The stock TPI system was designed for the 305. Running it on a 383 is trying to use an induction system designed for 78 less cubes. When I get around to my 383 stroker kit, I'm going aftermarket for intake plenum and runners, as well as a manifold.

Even if you weren't planning on running over 5500, I'm sure the stock setup would choke your combo before that point anyway. Might as well save up for a better intake setup - it'll look a million times better anyway when you pop the hood, too. The aftermarket stuff will also improve your torque curve a lot, so when it does start to taper off, it will not be as sudden. Not a bad thing, really... Depends on your budget, though.

 

I hear what your are saying about the TPI. The only thing is if I was to change the intake manifold I would like to re-use the wiring harness as I don't want to rewire the whole car.

There are just so many combos it is very hard to chose if you are not that familiar with parts etc... And you don't want to build something up and then be dissapointed. I have to check out the intake alternatives.

I was originally thinking of going with the SDPC base plate, Vortec heads. But I might spend a little extra and get something that won't need the base plate and sped it on something else. I guess it all comes down to $$$ and HP does not come cheap.

 

I had a friend that ran 383 with AFR 190's with a ported Accel base, and Arizona S&M runners. I'm not sure what cam, but he was running 12 flat. Never quite broke into the 11's although It's been a few years since I saw him run. You CAN certainly benefit from the 383.

...now of course, the question is how fast would a SuperRam or Mini-Ram be, on the same engine??? I'm sure it would EASILY be well into the 11's.

....I wouldn't put the TPI on a 383.


....on another note, I've learned 90% of what I know from this site. Stick around a while, read everything you can. Read the stickies about all the different intakes. You'd be amazed at what you will learn. I'm in the process of rebuilding my engine as we speak, and 3 years ago, I wouldn't have changed my spark-plugs by myself!!!!

The amount of knowledge here is AMAZING!:hail:

 

I don't disagree with above posts, but let me be the devil's advocate for a second. TPI is a TORQUE intake. More cubes from a stroker is goign to improve TORQUE, but not necessarily make any more peak HP given the airflow constraints of a stock (or near-stock) TPI. It's TORQUE that accelerates the car, horespower is a by-product. If you're talking about a true street engine (modest cam, stock stall converter, modest gearing) that's rarely going to see high RPMs, it's going to be a MONSTER stoplight-to-stoplight especially through the first 2 gears (assuming you can keep the rear tires glued to the pavement). Just don't try to top-end anything really fast on the highway.

It comes down to- what are your goals and budget?

I'll bet a 383 could lay down 40+ more peak torque than an equivalent 350, maybe even more in the extreme lower RPMs. Peak HP won't move very much. Maybe 10+ HP, but it's certainly going to FEEL much stronger than that, and RUN much stronger than that modest increase would indicate.

 

That logic makes sense.........at first, but ya gotta figure in why the TPI is a "torque" intake. The long tubes provide venturi-like charge of air into the combustion chamber. Kinda like puttin' your finger over the garden hose. The Mini-Ram and HSR/SR and others flow WAY better (bigger garden hose), but they suffer down low. I'm assuming most of us know the drill...

...we all say that the TPI runs outta breath around 4500-5000 RPM's, but we take for granted that it's based on the air needs of a 350. Heck, it'll breath up to 10,000 RPM's if the engine's air needs are small enough. (theoretically of course). And likewise, it won't flow past 3500, if the air demands were big enough. The 383 uses more air than a 350 at the same RPM, so logically, the TPI will run outta breath sooner on a 383. (lower RPM).

To be more precise, we should discuss how much HP the TPI can provide air for, not how high an RPM it can provide air for.

Some guys like to build 305's, some guys like the long tube TPI. It's all good, but there is NO WAY the TPI "should" be used on a 383.

 

I appreciate the comments! If I had a car running 12's that would be awesome probbaly more then I hoped for

I have to do more research and yes the inormation on here is unbelievable! What would we do without it.

 

Instead of getting TPI base for vortec heads and aftermarket runners why not just get a Mini ram III
or a GM RamJet manifold? You should be able to use your stock wiring harness (may need some minor mods)
GM sells a manifold and fuel rail kit for the RAMJET.

 

I am currently experiencing this exact problem with TPI. I have a new 383 with cam, headers, 52mm BBK, etc. and I just had it dyno-tuned. Needless to say, they couldn't do much for me because I have a stock 305 TPI setup. It choked at 4,200 rpm and didn't even put out 300 rwhp They recommended the Accel SuperRam base, plenum and runners because the stock TPI setup is not adequate enough for the 383. They said that this should free up about 100rwhp. Now I've gotta spend more money!!!

 

Given the same cam, intake and heads, the 350 and 383 will make close if not the same peak horsepower. Given the same a 302 and a 400 will make the same peak horsepower. Although the bigger the engine the more horsepower under the curve will be made. So in effect the bigger the engine the more power it will make. But the peak horsepowers will be equivent in value but occur at different RPM's.

The heads, cam and intake determine how much peak horsepower will be made not the engine size.

 

IroczInOz ---

I just put a 383 in my 91 Formula for my old 305, used the complete SuperRam intake system (plenum, runners, and intake), and I didn't have to change the harness at all for it.

Have a Great Day!!!




- Vern

 

You guys love beating up on the stock tpi system. It's the stock intake and it is here and has it's place whether we like it or not. I had the stock intake on my car, 383, afr heads, small cam, headers, etc. and the car went mid-high 13's at 101-102 mph with the stock chip and gear, tb, etc.

Was it optimal, no. But for someone who wants to shift no higher than 5500 like he stated, it will work with some aftermarket runners, a ported or aftermarket base, stock gear and 2800 stall convertor. Just because it can't breath over 4500 rpm doesn't mean you can't make it work. Use a lower rear gear, like a 2.77 to pull the rpm's back down in the torque after the shifts and it will run good at the track and on the street. Everybody wants to shift at 6500 rpm and run a 4.10 gear, and you can't do that with the tpi components, even the superram.

TPI has it's place, you just have to match the components. Mike Crew's car is a perfect example of this.

I need to stop posting here, I sound like a rambling old man sometimes. This board has turned into parts-bashing instead of a useful information exchange.

Another tpi combo:
http://temp.corvetteforum.net/c4/joe90/index6.shtml