Hopefully I can get some input from a few different people, any helpwould be appreciated. Here goes... I am building up a TPI 350 with L31 vortec heads, solid roller cam( don't know yet what the knck sensor will say about that!) modified stock TPI base to fit vortec heads, headers etc. What I am tryingto research is the vacuum requirement at idle for the TPI. What does it like? I want to run a CompCams solid roller, around 225-230deg @.050". I know that the TPI won't support properly the peak RPM of the cam, but I want to test the Modified stock components. Any info and/or experiences are appreciated. The stock 305 runs around 20" of mercury at idle. I'm not afraid of increasing the idle to 900 RPM on the 350. Thanks all...

[This message has been edited by arthur (edited October 25, 2001).]

 

on a SD (MAP) 16in is usually lowest. anything
lower consider DFI. MAF ive done some 14in
vacuum. was hairy, but doable. if auto, get a
converter. stick, get some gears.
airdeano

 

Hi, i am interested in know how you got your stock TPI base modifyed for the Vortec heads? How much did it cost & who can i contact? Please let me know because i am trying to peice together an affordable combo. THX

 

TTT

 

Traxion is running a 230/244 HR on his 350 Miniram with the stock computer AND he just passed emissions too.

I disagree with Airdeano about SD. You can easily modify the eprom on the SD car to work with a fairly aggressive cam and get a reasonable idle, many guys have done it. In fact, playing with MAF, I found it has a greater problem with idle on big cams due to reversion through the intake. That, and the "maxing of the MAF" issue.

The biggest challenge you will have is the mismatched intake/cam combo (even if it's short term). It will be a problem to tune because just when the cam wants to take off, the TPI will give up. I wouldn't even be surprised if it performed poorly. I would strongly suggest doing it right and get the proper intake to match the cam. Then you can do some proper tuning to make it perform like it should.

 

ARTHUR, where can i get my intake modifyed to fit the Vortec heads & how much does it cost? Anyone with this info Plz reply.

 

ANYONE!!!!!!!!!!!!!!!!!! ??????

 

Thanks for the info guys! As for the ported intake/modified intake for the vortec heads, I will be doing that myself. I have the resources at my disposal, and the cost would be labour. So to get someone else to do it would be expensive, and you might as well get the one from SDPP for $400. I have decided to not go with the solid cam. I've had good luck with them before, and wanted the extra benefits. I'm looking at the Comp Cams XR276HR,or maybe the 270. Also I am trying to figure out how to use flat top pistons with the 64cc vortec heads. A flat top hyp. piston with a 7cc valve relief and a 0.035 quench area gives a compression of 10.2:1. A little steep for the iron heads. What I am trying to find out is if the rollerized 305s had 100% dished pistons, or are they the D-shaped dish. I know that the 9.3 and 9.5 compr. 305s performed well on 87 oct.fuel. With a much more efficient chamber design, better cooling, tight quench, and good ignition, will allow the 10-10.2 ratio to operate without detonation. As for the stock TPI,how effective is the siamesing of the stock runners and/or base for upper RPM. Thanks again and will post more later...