Has anyone on here fitted the hi-flo TPI setups (namely the edelbrock base and runners) to a Stock 350? ie, standard heads/cam. Was wondering if it made a noticable difference, or if its a waste of time and money upgrading unless you change your heads and cam too.

The TPI setup was designed for the 305, and from what i've read GM made no modifications for higher flow required by the 350 (or, does it?). I'm sure they had a reason for not doing so that is beyond our understanding because I sure as **ll would've increased the flow.

I use the SLP base with the stock plenum/runners, and modified stock TB to 52mm, but nothing else is stock not even the block.

Let me say this - if the engine doesn't need anymore air a highflow system won't make a diffience.

Correction that's a Scroggins Dickey intake.

arent all the hi-flow base's the same, i.e. edelbrock, accel, tpis?

The restriction is the MAF sensor.

But, if the standard TPI set up was for a 305 then it must be
restrictive on a 350,
everything says it is (books etc)
they claim 20 hp on stock engine, with the edelbrock set up.

reason for not changing it for the 350 is money.
I read that when it was designed, they only planned on using
the 305, but then decided to have the 350 too,
but in true GM fashion, would not spend money to redesign the manifold.

The MAF is not too bad at lower power levels, descreened helps.

someone must have done this swap and felt a difference.. or not,?

I installed a 350 crate motor and used the TPI system from my original 305 except for the SLP runners and the usual for a 350 (FI, knck sensor, prom etc). I did change from the stock Maf (450 airflow) to a Wells (750 airflow) and the difference from a stock L98 TPI 240 HP (highest rated) to mine was increase to 288 HP (dyno'd).

288 hp,
i suppose a stock L98 with headers and a decent exhaust would make
a fair amount more than the factory 240 odd
but how much were the runners doing i wonder.

SLP been selling those runners since 1986 and that is a long time for aftermarket part. I remember the original ads and the quoted 20 HP which I don't belive now.

maybe more like 10 and maybe another 10 from a base manifold, maybe.

I did the scoggin dickey base plate, slp runners but also did the vortech heads and lt4 hot cam. You can get those heads dirt cheap and I recomend the set up. You won't be disappointed or feel as if you wasted money. For the seat of the pants feel, Mine feels like it's doubled.

There are a few articles on this subject in the mag section. I have an edelbrock high flow intake manifold w/ high flow runners port/matched. Id say together they are good for 20-25 hp but I also had them ported by TPIS.

Read the following article for what is the best flowing TPI intake manifold base and runners.

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

Now this article indicates what flowed best for a 383 cubic inch engine, which pulls in more air than a 350 cubic inch engine and certainly a 305 cubic inch engine.

If you prioritizing what to upgrade on the intake side of a 350 TPI engine to produce the best horsepower and torque results I would suggest the cam and heads first then the intake base manifold and runners. The cam is the easiest and probably cheapest item to install to reduce air restrictions. The heads would be the most expensive to replace. If you were doing the heads and it was in your budget you would do the base manifold and runners at the same time. Of course you would need to select a cam, heads and intake base that all worked together and which worked with the exhaust side of your engine as well.

Sorry this is the link to that article.

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

You are getting into some expensive parts. The intake and runners are basic bolt on mods that really free up horsepower. Here are some cheaper mods that got this bird to 290 hp fairly easy. Awesome article you found there btw.

http://www.gtasourcepage.com/91GTASLPTest.html

Idealy i would of course change the heads, cam and intake all at the same
time, tho as already said, that gets expensive.
Something around the lines of the LT4 hot cam is probably a good idea tho,
or something very similar, dont wanna go too wild and need to change torque
convertor etc.

My thinking was possibly change the manifold/runners this year and
then maybe do heads/cam next year, when hopefully i have more money
(things a bit tight right now)
Tho not sure if it is worth the expense for 20hp ish, although it
would certainly split up the cost.

I was surprised by that compcams article tho,
it showed they managed to make 410hp with their engine with a
stock TPI setup,
a lot less than the engine was capable of, but still alot
more than i thought it could do.

I don't think it's worth it either, the reason I stated how cheaply you can pick up those heads for is because if you do decide to get them later, like you said to split the cost, the intake base design is different.
I would wait or just pick up the parts here and there as money permits, and then swap it all at once so you can feel the impact of it all together. The first drive after the build (ear to ear smile)made me totally forget about the money I saved and spent.

i put them on my 305 with a ported plenum.
My little 305 with the stock heads dynoed at 175rwhp on a mustang dyno.
211 tq My peak HP was around 4666 rpms and 4955 rpms.
Where it usually fell on its face at 4500rpms.
Of coarse I changed more then just the base and runners though.

Do it all at once. This will save you your time and/or labour costs, gasket costs and other costs such as has been mentioned. Formulate a plan, save the money and do it all at once. Research this board and watch other board and stores for sales and do it all at once. Oh yes and did I mention do it all at once.

Yes, i think you are right, best of waiting and do it all in one go.
Makes sense.

Thanks for your input.

I was not going to do it all at once either, but I only wanted to do this once so I have been saving here and there and bought all the parts. now i am slowly putting it back together!!!! before i started to take my car apart, I dynoed my 305 at 192hp and 260 ft. mostly stock. Now i am putting a set of pro comp heads 58cc and the edelbrock high flow base plate on it with hooker headers and 1.6 roller rockers. i can not wait to get it together and see how she does!!!