Paul G

I am thinking about adding more power this winter. Current mods are in sig. Pulling the engine and having the block modified to a 383 is on the list. If I do the pulling and putting what will this cost me for the crank and machine shop work?

I live in a smog check area so loosing the cats is not an option. Headers will require me to remove at least the pre cats. That may be okay if the inspector doesnt know the difference.

If I stay with the stock heads and stock TPI will I see any HP gains or 1/4 mile improvement with just a 383 block?

Are new heads like maybe the AFR's actually better than porting my stock heads? Worth the cost?

I am also thinking about other types of induction. I like the Tuned Port look. I could go with the LPE big mouth base and runners with a 52 or 58 mm TB. Will they retain the stock look? I have never seen one of those systems in person. Are the gains with this sytem big enough to justify the cost? I figure around $1500 using my upper plenum and porting it.

Then there is the Super Ram intake system, and Mini Ram intake system. Which performs better with a manual trans?

TPIS hawks the Mini Ram as adding almost 100 HP, no mention of torque. Will it really add that much? Problem with the Mini Ram is it's so ugly in the pics I have seen. I like to show my car on the weekends as well as enjoying the performance. The Mini Ram with a 58MM TB will run about $1800.

LPE's site says the Super Ram system will add about 60lb feet of torque at 5800 rpm. No HP numbers. This will run about $1800 with a 58MM TB also.

I am sorry for the long thread and all the questions at one time. Some help with the planning now may make a huge difference in the outcome when I am done. TIA

P.S. I could just take the money I have for upgrades and go get an LT4 car and be done with it. And no bloody knuckles to boot.

Mr. Magoo

Some people might say a MiniRam is better with a manual Transmission, but if you ask Kamarossrs who has a 383 AUTO with a MiniRam..............he'll tell you his Vette runs great down the track with a best of 11.7 without much tuning. :D

jburnett

My personal opinion for a 383 with excellent street manners and bulletproof reliability is the SuperRam; particularly with an automatic. My wife's '85 runs 11.70's with a MILD SR 383; and when I say mild I'd drive the thing from here to California and back and not bat an eye. IMO the SR is the better piece for a street driven mild combination. Now, if you talk about radically camming it, installing deeper gears and more converter and plan to spin it higher then go with the MiniRam or a converted single plane. But the SR is simply the best "street" manifold for TPI's that I can think of; you don't have to rev it, big rpm hurts reliability and with the low and mid range of the SR it's simply friendlier.
-Jeb

Nathan Plemons

The largest drawback to your current TPI setup is it's inability to flow enough air at higher RPM's. As such the motor "runs out of breath" at a certain RPM, most accounts claim this is around 4500 RPM's for a stock L98. If you turn this motor into a 383 you will have greater air demand for any given RPM, essentially you'll run out of breath sooner. You'll make more power, up until that point, but that point may be at 4000 RPM's now.

The big mouth TPI is still a TPI. It will run out of air fairly low in it's RPM band. The Super Ram is a nice intake but it is still tuned for low-mid range RPM's. If you want high revving power the Mini Ram is the only way to go. It is a very short runner design which is made to flow very well in the upper RPM's.

The drawback to this design is that it does give up some low end torque. Ideally though the extra stroke of the 383 will compensate for the very low end torque that you would be giving up. The end result would be very respectable low end torque and brutal mid-upper RPM power.

Of course with the intake restriction out of the way you'll just move down the line to your next restriction, which will probably be the heads, followed then by the cam.

vader86

Not a TPI, I wouldnt do that. Its just not going to flow enough for the 383.

Superram has a CARB number, so with tuning it will be emissions legal, provided you dont get crazy with the cam choice. I believe the 219 cam does have a CARB #, but i'm not sure.
Lingenfelter builds his 383 SR engines with the D-port heads, so AFRs are not strictly necessary. But you will need porting. His SR 383s with the 219 cam put about 440hp to the crank. emissions legal

Miniram should pass emissions if you go with the right cam. Dont get too big though. Their advertised gains are skewed, you have to think about the testing. Remember the TPI doesnt really make HP over 5K, and the MR can let it spin up to 7K and still feed it.


[Modified by vader86, 10:49 AM 9/10/2003]

J Z06

A 383,219 cam and a super ram are a tried and true combination.

You'll do very well at the strip while retaining a nice street motor with gobs of torque.

Just my .02

ralph

Oh no, not this again!!!!!!!!!!!


However, the more i study this, the more i have to agree with Jeb. I'm currently looking at opitons for my nephews LT and that intake wants to make power from 5000 rpms to the moon. So if you are willing to setup your car to operate in that rpm region, the sky's the limit. But if your primary use is the street, you're going to have to make compromises. The SR is definitely limited at the top end, but will make a ton of torque/hp in the lower rpm ranges (under 6000) which is more in line with street use. You can decide where you want to operate and have fun!!!

SBNova

One intake nobody has mentioned is the Holley Stealth Ram. I know, I know it doesnt fit under the hood of a C4 without modification. But you are talking $1500 for the other intakes and this one is less than $500. I would hope for $1K it could be made to fit. I know there are forum members selling modified tops, but a decent welder/fabricator should be able to make it work for +/-$100. I believe with its decent plenum size, large runners of decent length this would be optimal for power with a larger engine.

robert5168

i have a 383 and it is so danm fast!! i had my pletum bored to match the big mouth runners, so to answer your question i have the TPI big mouth. read lingerfelter's book, i used his cam. if you loki i could fax you all the work i had done my a shop here in new orleans. it costed me 3 to 4 grand. i also had my sister's car done

HeaderDesign.com

If you like the look of the TPI engine, which most people do, you should just design for best use of that basic configuration. Most people don't even come close to getting the available performance out of their TPI or improved TPI.

Also, the TPI long intake runner engine responds VERY well to increased displacement, with marked gains everywhere below the top of the power band. It also responds very well to improved heads and runners, and much more than stock intake duration on the cam. The TPI is not "flow" limited. The stock 25" intake runners are responsible for the power peak at 4500RPM because of wave action. Improved heads, cam, and improved 23" runners will move this power peak to 4700RPM, and form another power peak at 6200RPM. The RPM of these peaks is not particularly sensitive to displacement.

You can build a 10.8:1 383CID TPI with AFR190 comp ported heads, about 2.18in^2 improved base and runners, and correct cam and headers that will produce about all the power you can put to the street. It will produce about 450HP from 4800-6400RPM, and above 500FT-Lbs from 3400-4400RPM. This broad power range is a great match for the wide-ratio ZF. It will idle almost smoothly, and won't need a rev kit to hit the shift RPM. You will need the correct rear gear ratio to make best use of the rev range.