heres my plans i have a 91 z-28 and it has the TPI. as i was walking through my buddies junkyard i found a set of 5.7 vortec truck heads. so i searched around to see what it took to put them on. so far i need the edlebrock 3817 intake conversion deal that bolts all of it together. but then there is the i want more power issue. ive heard the limit to the vortec head is that you cant put to much of a cam in it for some reason. but the machine shop guy said he could take the stock heads and cut the seats and make it so i can fit better valves and a larger cam in it. Heres my issue. im trying for as close to 500hp as possible and just like the vortec head idea. so how big of a valve should i put in it? springs? and i want it to be hydralic roller to. purpose of this car is my play toy i like driving it around but i also play around at the strip with some friends. im currently waiting on my detroit tru track and 3.42's cause i blew up the old rear. (stupid 10 bolts) so any ideas or advice. for now its an idea that im planning and pricing out.

First off, this isn't a fabrication related topic.

You should do some searching on here. There are quite a few vortec TPI combos on the boards. - 500hp out of LTR TPI isn't the easiest thing to do.


With a 500hp goal, I would use 2.02/1.6 valves. The heads will need the appropriate porting to smooth the seat transition, as well as opening them up to flow enough to feed 500hp. The cam lift problem is on the vale spring side, and has to do with the retainers coming into contact with the valve guides when used with higher lifts. Any good cylinder head shop will have the equipment to cut the guides down properly; with the proper components and set-up they can be used with pretty decent sized cams.

All that said, unless you're getting a killer deal on the machine work, porting, and the valvetrain components, you would be conisderably better off buying some complete aftermarket vortec type castings. RHS makes 2.02/1.6 casting that outflows a stock vortec considerably, and has the dual intake patterns to accept either a vortec-bolt pattern intake or regular sbc pattern. - It will cost you less in the long run and you will have a considerably better casting than the stock GM heads.

As for reaching a 500hp goal with a TPI; you will need large aftermarket runners, a hi-flow base, and a fully ported plenum to even think about it.