Arctic_Z

I've been collecting all the parts to convert my lt1 to a lt4. I bought some ported and polished lt1 heads and intake to match from a friend who had them on his vette. The guy I bought them from says they flow at 270 cfm but still have stock valves. He was pulling 10's with these and a vortech supercharger & LT hdrs and of course other goodies.
I know that lt4 heads are 2.00 intake & 1.55 exhaust, stock being 1.94 & 1.50. I'm wondering is it worth upgrading? How much would this cost me to do (valve job)? Are the gm sodiums worth the money or should I go with the manleys? How much more gain would 2.02 & 1.60 get me and what are the downfalls if any? What about 2.05 or 2.08 with 1.60?
I have got the LT4 hotcam, LT4 springs, comp cam lifters & pushrods, 1.6 gold crane roller rockers and BBK 58mm throttle body for this conversion sitting here in my office. Bolted on the car already are BBK headers, SLP loadmouth, SLP CAI, Granatelli MAF and MSD 6al ignition with blaster coil, hypertech 160 thermo and programing.
I'm ready to bolt all this on, but wondering if I'm gonna kick myself in the *** later for not doing the valves. Is it worth the money for more HP gain here? Where do you think I could come in at on the 1/4 mile with this setup?

amean94ta

first there's no way you have that much flow with stock valves not at 28 inches of h20 anyway so you might wanna have them flowed yourself. you say you got lt1 head's and a intake? thats not gonna make a lt4. beside's the lt4 is overated anyway you can do much,much better. valve job at my shop is $150 i suggest you have them put larger seats in the intake and use 2.02 manley pro flow valves on the exhaust you dont need new seats to run a 1.60. if you wanna run fast ditch the hotcam and those springs and pick up a gm847 or cc306.