I picked up a 2001 GM crate 350 with 40k miles. Roller cam motor, but it was a TBI setup, which I'm not going to mess with. So those heads will be hitting craigslist along with the fuel injection setup. In the meantime, I picked up a set of 062 vortec heads.
I've read I can use LS3/LS6 valve springs, Comp Cams retainers, and Dodge Daytona turbo 4 cylinder valve seals. This will give me up to .550 valve lift before coil bind (stock limits were .490 I believe). I am going to run an LT4 hot cam and 1.6 GMPP roller rockers which give me a max lift of .529.
My question is, is there any reason to go to the larger valves (2.02/1.6) or will the stockers be ok for my setup?
Also, I've read conflicting opinions on whether to do any porting or cleanup. Some say the vortec heads really benefit from bowl blending and opening the exhaust port around the valve guide, others say not to touch them unless you're going over 425hp.
What say you?
I'll start with a few questions, which I always pose to an engine build query....
What's the engine going to be doing?
It's been a while since I've really dug into cam numbers, but .529 is a fair sized lift IIRC. What kind of duration is the cam? What's your target powerband? Just based on the little bit of cam numbers you're showing, I'm guessing you're looking at a high RPM powerband. What's the compression ratio going to be?
I'm not familar with those heads, but can they support the extra flow that the 2.02 valves will allow? Or are they narrow valve heads that you're just going to cut bigger seats into? Do your pistons have the clearance for the cam/valve combo you're looking at?
2-bolt or 4-bolt block?
I'm not a big fan of randomly slapping engine parts together and seeing what they do, I find things work out so much nicer if you start with a target performance level and build to match that.