Where is the limit with the stock base and runners on a TPI set up.

I have went 11.91 with mine ( stock) and a 150 shot, i don't have the funds for the aftermarket stuff, so where could i go to with porting the stock stuff and a heads and cam change.

i have an stock 85 vette.( with the cast iron heads)

i was thinking of a 224-236 Comp cam nitrous cam and i have a set of Dart iron eagle 180 's.

If any one would have any suggestions or share their combo and times i would appreciate it.

Thanks
Mike

 

See sig. for combo.

 

i like your combo, but i see you have a SLP runners and plenum.

I'm looking for stock ported base and runners.

thanks though.
Mike

 

The SLP runners are about as cheap as you cn get. If you're not wanting to spend anything on runners at all I would port the base/plenum and modify your stock runners so that they are siamised. Someone on the board did this by cutting the tubes and making 2 into 1.

 

thanks

 

Actually I have the stock plenum (I ported it) and I ported the SLP runners to match the upper and lower.

That cam you picked is too much for a ported stock TPI intake/runners. It wont be able to flow enough to keep up with that cam (even with Nitrous). Unless you go with an aftermarket intake, you'll be running out of breath at 4,800 rpms where as that cam you picked peaks at 5,800 - 6,000 rpms.

Just a thought!

 

you could still follow 91z's combo except use Arizona Speed and Marine Long tube runners. They have a very stock appearance....just better cfm.

 

Ok - you said you wanted stock TPI. So, going from that assumption, I am able to offer some broad advice to you. Basically, you port the plenum, big time. You match the runner ends to the plenum, and the same goes for your base. You can siamese a stock base but not too far in. As for the cam, you want a relatively low lift and a long duration. Even tho you have nitrous, I would match the cam more in concern of the TPI, since it needs to be catered to due its limited powerband. The nitrous will add all sorts of power still to that applicable powerband.

 

thanks for all the suggestions

 

Thought the tpi preferred the opposite, high lift and short duration since the duration bleeds off comp resulting in low vac which causes problems with the ECM (esp with a speed density)?

 

I am pretty sure it is low lift and long duration, but... I would hate to offer tainted advice. Can anyone back me up on this?

 

I'm thinking big life, short duration. Thats why the ZZ4 is so popular. Short duration 208/221, big lift slightly over .5".

 

Ok so I had it backwards - my apologies guy who wanted advice