davidGTA

iTrader: (2)

building a mild engine for the street for my 89 GTA, what i am planning so far....

-new L31 short block GM part # 12556121
-AFR 180cc heads http://www.summitracing.com/parts/AFR-0919/?image=large
-lt1 intake set up with stock lt1 injectors

only questions i have so far are:

-what is a mild cam to use?
-is there anyone i can go to to modify a lt1 intake for me?
-the afr heads are 65cc which would give me about a 9.1:1 compression ratio, would it be worth it to mil them to get a little more compression?

sinkorskin

The L31 is a Vortec headed 350 out of 1996-2002 chevy and gmc pickups. Lt1 intake manifolds are proprietary to Lt1 engines only due to the reverse flow cooling pattern. An Lt1 intake just plain wont work. You could get a mini ram intake which i believe is identical in specs to the LT1 but it will work with the heads youve selected. I think it would just bolt on and work without any ecu programming. There is also the stealth ram from holley and BBK recently made a TPI manifold (upper plenum, intake and runners) but im not sure its in production yet. Those would be your only easy options for manifolds. Comp cams makes some emissions legal cams but i wouldnt call them mild. They are far better than the Edelbrock performer series for your engine.

five7kid

iTrader: (14)

I think he knows what an L31 is. He's simply buying a new shortblock from GM (a good base to build on).

I haven't heard anything lately on a source for modifying an LT1 intake for use on an SBC, except that the guy everyone used to go to is no longer doing them (don't know why). But, , you may find something useful.

I'd agree on the Holley/Weiand Stealth Ram. It isn't emissions-legal, but neither is a modified LT1 intake.

A mild cam would be something like a Comp XR26x cam.