As far as top end and torq goes which motor do you think is better with the stock tpi intake

 

Neither.
Both are going to be severely restricted in breathing with a stock TPI.
Some guys run modded TPI's on 383 ; awresome bottom , pull stumps out all day end but nothing up top.
Remember a stock 350 TPI is dead at 4500 so a bigger cube engine would run out of puff sooner.

Read link below to see what intake change does on 383
http://www.compcams.com/Community/Ar...?ID=1737510521

 

what about the mpg

 

what you would have to do is port an aftermarket intake and aftermarket runners.... it's the only way, however, some say that even then you will not have the full benefits of your engine... well I think 400 RWHP is enough, don't you think? ... the way I'm thinking of going once my 383 project has funds to work with, is I am gonna go with a Edelbrock Hi-Flow intake, and AS&M runners... I have emission testing to worry about... so if the intake has a CARB EO number, I think I should be able to pass with the runners... they look somewhat stock..

 

i guess it would be enough i just want to give the challengers and camaros hell its going in a 1980 pontiac lemans

 

The 383 is a better size for TPI. You will need to port it quite a bit but you should be able to make good power. Remember to match your cam to the RPM range of TPI, so nothing peaking over 5000.

 

wait a minute, shouldn't ported aftermarket TPI hardware allow it to have a wider RPM power band? aren't Corvettes up to like 6k... could be wrong though, usually I am...

 

Welcome to the TGO Universe!!!!!!

A TPI intake was made to produce Tq in the first place, and it does this very well.
vetteoz is right when he says that the 350TPI is done by 4500 RPM.
But may I ask.... what's wrong with that???

Maximizing overall USEABLE POWER always results in a quicker car.
Nothing wrong with making an engine with 600hp, but if you need to spin it at 7000RPM to get there it's not a street car....and I don't think it's fun IMO because you'll be hard pressed to Rev like that in a street car

I'll argue that making great power under 5000 RPM will always be a great street car that always has power on tap.
I'm struggling with the same decision right now....

If you're making 500+ ft/Lbs of Torque from 2000-4500 RPM who are you losing to? As long as you have another gear to shift into..... Now you won't have HUMOUNGOUS HP #'s to brag about, but who cares when you lift the tires off the ground???
By the way....What gear ratio are you running in the back? Turbo350 tranny right?

Don't get me wrong.... a big inch small block is gonna need a large aftermarket TPI setup!!! and great flowing heads to say the least.... But I think that you'd have a blast with it.

How's that for starting a discussion....
I'm gonna sit back and watch the fireworks

 

The most important thing to remember in building a motor....
Cyinder filling, it takes air and fuel to make power and torque.
If the intake system won't allow enough air, you're not going to get HP & TQ.

Your basic base manifold will not work with a displacement over 355 CI.
We have got them to flow a little over 300 CFM and that works, but is marginal for 383.

At 300 CFM the RPM range max is about 6200-6400

HTH

 

A 383 with the Mini-Ram or Stealth Ram can produce damned good numbers for a street car. Stock TPI is just too limiting.

 

WELL IM GOT A 4L65E STAGE2 WITH A 3.42 REAR END THAT WHAT IM RUNNING IN A 1980 PONTIAC LEMANS

 

i also have the efi connection wire harnsss with the ls1 computer so hopefuly that should also squeez out some hp and gas milleage

 

I'm thinking about that same setup to go with a mini-ram on my 383 build.

 

how is the mini ram working for you

 

I haven't got one yet. I'm still gathering parts for the build. A friend of mine had one on his 350 and he liked it a lot.

 

sorry i took so long to reply im running 3.42 rear end and a 4l60e trans its pushing a1980 pontiac lemans

 

You must be right.....

410hp/510ft lbs torque on a head/cam/tune under stock TPI plenum/runners/plenum shows just how limiting the TPI stuff is.........

 

Check this link

http://www.compcams.com/Community/Ar...?ID=1737510521

Even the aftermarket TPI style intakes are stop making power @5K but make impressive torque down low

 

those torq and horsepower figures from the comp cam intake shoot out does not seem too limiting for a street engine to me.436hp and 534ft of torq and a 383 is very impressive.but it would be even more powerful with a 408 tpi sbc even a 400.

 

Show me how to make that kind of power and torque under a stock TPI plenum and runners then. People don't often see those kinds of numbers even on ported setups and in some cases not even with a Mini-Ram/Stealth Ram/Super Ram. If I could make that kind of power with the stock TPI setup, then I'll definitely do that. I love the way TPI looks.

 

vetteoz has already posted a link to the article twice in this thread. Post #2 Post #17. I guess third time is the charm.....Here it is again.....
http://www.compcams.com/Community/Ar...?ID=1737510521

I actually have that issue in print, sitting right here beside me.

I just can't find anybody that knows which specific heads were used. Only the manufacturers name.

 

how your engine is tuned plays a important part.the cyclinder heads.compression ratio, injectors, full roller rocket arms will help you get that type of power and power ignition system,throttle and the runners you use.swicth over to a ls1 ecu to control the motor on a 408 or 400 even 383sbc you will see a definite power gain vs a flashed or stage three e prom

 

it is possible to get that kind of power

 

Typical dyno queen motor. Drop that in a car and watch the RWHP fall into oblivion. I'd be shocked if it put more than 300 to the wheels. Meh.

 

And farther down on that page it shows where the TPIS miniram made 500 horsepower. That means the stock TPI setup is restrictive.

 

We all know there is a difference between flywheel HP and rear wheel hp. But 100hp loss? I doubt it....

 

a stock l98 head tpi 383 with a mild cam makes more power than 300 at the rear wheel even with a th400 trans because you will loose the most power at the wheel with a th400 trans because of the power that is required to rotate the mass inside of a th400 tranmission.hell a maxed out 350 tpi would still make more power than 300 rwhp,on a queen dyno and mustang chassis dyno.Btw we are not talking about a typical 305 or 350 motors.we are talking about 383 stroked tpi sbc,or the biggest gen1 production sbc which is the 400 or a 408sbc which is a 400 bored over .080,the point is these motors are nature born torq mill.torq = hp

 

On the top end, yes. Everybody has always known that. How much $$$ did the extra 100hp cost? Wasn't cheap. Look at the hp and torque curve, not just the highest # achieved. Besides.....Highest possible hp #s are not everyone's goal. Low RPM is what moves a street car, not horsepower. Give me the the low RPM for my street car.

Look at what the Extrude Hone & large tubes did.....Good gains, but they still works great for ME.

Everyone has different goals. The stock upper end is perfect for ME & possibly for 87WS6 too. My goals steer me towards stock upper end & leaves me $ to spend elsewhere.

 

I saw the curves and do agree that the stock TPI setup had a nicer looking curve. That could be because then the heads and cam they were using were not up to par with the miniram setup. This is where building an entire motor to match eachother comes in.

I also wasnt trying to come off like the stock setup is worth nothing. If its good for your motor and what you want out of it, then thats great. Saves you money. Everyones motor (besides all out race motors) have some power they could gain somewhere by switching out something. I was just pointing out that just because a stock TPI setup CAN make 400+ horsepower, doesnt mean its not restrictive in some form.

 

i agree i now purchased the elderbrock pro flo xt in place of the tpi intake .hopefully it will wake up my engine

 

F.I.R.S.T. INJECTION

 

.. The 408" (.040" overbore, not " .080" ") will, hands down, make more torque than the 383"... the stock TPI tuning cuts off HP about 4500 RPMs for 350, 383, 400, so the more torque you have by 4500, the bigger HP number you generate...

.. If you don't have to worry about emissions testing, the Accel/Lingenfelter SuperRam, Holley Steet Ram, Mini-Ram, or even an inexpensive used tunnel ram base modded with your plenum, injectors, and throttle body added (TPI = Tunnel Port Injection here) will make the most HP power and even great torque...

 

yea so far i got the pro flo xt with a ls1 tb dont know how would do but it should be better than the stock intake

 

OP theres your answer if you have to have a TPI style intake for the money its a bargain..



NEVER going to happen with a stock TPI intake, ever.
Throw that stuff in teh trash where it belongs and start with better parts.


383/400+cubic inch engines are air hungry and demand a lot.

 

yea i realize that so i ended up swicthing out to the edlerbrock pro flo xt intake.hopefuly it should wake up my motor.that intake with the efi connections ls1 coil setup and ls1 ecu should become a very strong combo

 

Till you consider that the Miniram and HSR are making 100hp MORE than the TPI with only a minor loss in torque, about 45lb/ft.

The TPI car would feel better all around town and in all part throttle situations because the revs would stay below 4000rpm. But once you put your foot to the floor and the engine heads north of 4000rpm the TPI is going to feel SLOW compared to a HSR. This is a stock TPI intake vs HSR comparison here.

My LT1 shifts at 6k, and the recovery with a 700r4 is about 4700rpm-5000rpm depending on the gear.

 

build the 408, use a solid roller monster heads 220-240cc intakes and a mini or HSR. Stomp the competition.
Stroke and gears move a street car also.
I spin my 400 ci unit to 8k all the time. its a street car.

 

I went a 12.20 a few years ago with completely stock, unported intake and runners on a 350 with just afr heads and comp 276 with the stock computer chip. Shifted at 5700. Had more in it with tuning, etc..... The pic in my sig was taken with that setup. I think that would handle most new challengers and camaros. Just sayin.....

 

.. Unfortunately, the new Challengers, and especially the Camaros, also go quicker with slicks on them...

 

.. The Eddy ProFlow is one of the intakes tested in the Super Rod tests sticky thread above... it didn't fare too well compared to the others (except stock TPI)... I've seen it tested in other places and it did even worse (like 360HP max)... But I don't know why, seems to be about the same short runner design as the Holley Stealth/Street Ram, so I don't understand why it's not performing about the same, at least HP-wise...???

 

well i have one of those eddy proflow and my mechanic was able to get the throttle body to work like its suppose to so I am selling it.I just lucked up and found some one that could mega port the **** out of my lower intake and runners so i will just stick with that.