Just wondering if the 083 heads off an L98 will respond well to porting/polishing and what could I really expect out of them or is it just worthwhile to go aftermarket.

 

Probably the best factory heads to work over.

A set of Pro Lightnings or World S/R Torquers would probably work slightly better, and unless you do the work yourself, would cost less than working over factory heads.

 

i am assuming that these could possibly make a 400HP 355 engine with a larger cam and some port work? or would they not flow enough? bigger valves needed etc?

 

Ported 083's with proper exhaust, cam, induction, etc., would make 400 gross flywheel HP easily.

 

i was thinking along the lines of the 274XE cam, or would you have a better recommendation. It'll be going on a Performer RPM intake, with a 750 holley on top. Right now it's a 2400 stall'd 700-R4, but can go to a 3000-3500 stall'd TH350 if need be later on. I already have long tube headers, H-pipe, and dual 2.5inch exhaust so that's been taken care of as well. Full MSD ignition as well. Just concentrating on the motor first. I want 400HP minimum and was thinking these would be a great excuse to port up compared to buying vortec heads, etc.

 

Sounds like a good plan to me. Porting, upgraded valve springs (follow Comp recommendations for the cam), and I'd have screw-in rocker studs installed while you're at it.