I had to make modifications to the SLP runners in order to be able to bolt them to the First Intake Manifold. Yes I'm using the factory plenum and factory style throttle body.

Yes you can buy the base separate. However it is not for the faint of heart to adapt the SLP runners to a First Intake TPI intake manifold. I also used the factory fuel rail system with some modifications. There is a thread over on www.thirdgen.org for those interested on how it was done.

 

what type of mods? Like welding on new material and tapping or...??

 

Basically cutting off 1.25" off the SLP runners where they meet the intake manifold. Then welding on new one inch adaptors with holes to line up with the First Intake manifold. Lots of filling in with welding material to fill the gaps.

 

From 1989 Car Craft. Test of TPI that includes the FIRST here.

http://forums.corvetteforum.com/show....php?t=1928281

 

Here are some pictures of the size of the FIRST plenum and runners vs. a ported plenum and AS&M runners.

 

Seeing is believing! Those runners look great but nothing compared to that plenum!

 

Damn, that plenum is awesome. No way will that not make a huge difference....Would be real fun on a larger CI TPI, should make torque like crazy. I dig it!

 

Man, this is going to drive me nuts for months. I can't do anything with mine for almost a freaken year!

On the brighter side, I'll be able to have all you excellent people work out the kinks for me!

 

At the rate I'm progressing, I may not have it done in a year!

 

Just for giggles, I ran a sim with a 434 cube short block last week using a FIRST and the same heads and cam I'm planning for my 383 (which would be pretty small for a 434) and got something like 580 lb-ft peak at 3000 RPM if memory serves correctly. Talk about face distorting torque!

EDIT: I just checked my sim. I got 585 lb-ft at 4000 with a 421 cube motor. The 434 made 599 lb-ft at 4000, with over 550 lb-ft from 3000-5000 and over 400 from idle-6000 RPM. The 421 was down about 20 lb-ft across the board except at peak torque.

 

 

Hmm. My 3 inch runner intake with a 421 wont be too far off!

 

HUH???????

Wow, just wow. How did you draw THAT conclusion from the comments presented here for a long runner intake with a HUGE plenum volume ????

Isn't that somewhat like comparing apples to elephants?

 

 

"Wow, just wow?" You mentioned a 434, I mentioned a 421. How is that apples to elephants? You said the FIRST with your heads which are the same as mine, and the cam you are using for the 383 on your engine sim made 580tq if was a 434?

This FIRST is getting alot of hype. Let's hope it kicks butt! Holy batman!


Nice ron!

 

I never thought the TPI could produce this kind of horsepower up top and keep the outstanding torque. I just read an article in one of the Chevy HP mags about a 383ci Vette L98 with big-tube runners (TPIS maybe?)that made 458 hp and about 530lbs/ft of torque with a very small Comp cam - something on the order of 211/218 dur and .490ish lift. It had Extrude Hone ported L98 aluminum heads, manifold base and plenum, with I'm guessing a 58mm throttle body. They said the ported heads flowed around 260cfm and the combo used a FAST computer for tuning (36lb injectors). It carried power until 5500/6000rpm. The motor originally had a Comp Magnum 270 single pattern hyd roller with about 215 dur and probably .500 lift (made 327hp and about 400lb/ft torque). I'd of liked to see the graph with that cam and the extra cubes/porting/induction. Bet it could have made more power than the new split duration cam.
Anyway, this First manifold setup intrigues me, so any dyno charts you fellas can post would be appreciated, even if it's just a table with hp and torque for every 500rpm or so.
Z51L9889 - Those new 195 AFR's are supposed to be the cat's azz. What would your motor's curve look like with the unported (or ported!) First intake and a less aggressive cam, say something from the Comp catalog with 230/236 dur at .050 and about .560 lift, assuming 1.6 ratio roller rockers? Maybe a small single pattern cam like the 270 Magnum hyd roller? I'm curious to see what those curves would look like, especially if they could run through the Hooker header/side pipes on my '70!

 

From the dyno testing we have done with modified TPI setups the Comp XFI230 cam looks like the way to go for power. The XFI268 seems to run out of gas at the 350rwhp mark with a stalled auto. That would be somewhere around the 375rwhp mark with an M6.

Yes on the new AFR 195cc Eliminator heads. They are proving to be awesome. The new Dart Pro One heads should be good to. I have not seen anything on those yet.

 

Wonder how this First Injection setup would have fared in this Super ROD TPI showdown in 2005?

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

It seems to be a lower-lift version of your cam, Z51L9889. Your torque numbers look to be in the ballpark with their results. I think your heads would spank the TFS heads they used in their test 383 though! Probably why your simulations predict 60 more horse than the TPIS long tubes they tested - that, and some added runner/base manifold size.