Chevyguy1984

I'm installing TPI (1986 MAF system, off a 5.7L) in place of a carb on my current motor. The motor is as follows:

355 with forged pistons, 9.8:1 compression, fully ported and polished 487 casting heads with 2.02/1.60 undercut valves, comp cams xtreme energy 268H cam (224/230 @ .050 and .470/.480 lift on 110 LSA), 1.6:1 roller tipped rockers

What can you suggest I do to the stock TPI setup in order to work with my current combo short of going to a miniram or superram setup? I've already got an airfoil, an adjustable FPR, ported the plenum out behind the throttlebody and I've removed all flash and smoothed the base. Would siameseing the base in about 2" help significantly in this application, and does this mod bring any ill effects? What about runners/throttlebody/injectors? I'm shooting for about 340-350 crank horsepower and at least 380 ft/lbs or torque with these parts, is this attainable? Thanks and sorry for all the questions.

D Stroy H8

Siamese the runner ends, not too deep or you'll give yourself a headache repairing them. Then match the ports on your plenum and your siamesed base. Thats about all you can do short of cutting the ltr's up and making a total custom weld job to attain bigger runners. Heres something I've said repeatedly in the past 5 days - Edelbrocks TPI runners/base is 650.00 in summit right now. Edelbrocks stuff will outflow a ported stocker straight out of the box & theres room for porting if you wish to make them even better.

Good luck with whatever you decide to do - trading in a carb and going TPI. Awesome.

Chevyguy1984

Awesome thanks. I think for now I will purchase either Edelborck of SLP runners and just port the plenum and siamese the base to match them. Than at a later date when funds are more plentiful pop for either an Edelbrock or Accel base. I figure the runners and the porting should give me decent power for now and when I want more I can always just swap in the big mouth base.