I asked on another thread but never got a specific answer. I'm in the market for a new cam to put in my stock block and heads. The heads may or may not be ported, I'll find out today when we talk to the machine shop guy and get a quote. My question: is there a rise limit for the stock heads (springs, maybe valves, new rods and lifters though)? If I port the heads I may like to do a lift in the .480-.490s (nte .500). Taller valve covers are a given but what can stock heads achieve or be limited by? Could I conceivably do a .512 lift if I wanted to using stock rockers and springs?
You would need a spring upgrade at the very least.......IIRC you can do a .440 lift on stock springs etc.....but ask a machine shop guy he will know for sure.....and imo why not step up to a good set up roller rockers... The limiting factor on stock heads if they are the older ones is the rail mount rockers......you will need to have studs installed anyways.....go roller rockers.....JMO
m-6250-a312 ford racing This cam works excellent for driveability and good power. http://www.summitracing.com/parts/FMS-M-6250-A312?part=FMS-M-6250-A312&autoview=sku
The limiting factor is going to be the pressed in rocker studs. Anything over about a Comp 268H will increase your chances of the studs being pulled loose due to the increased rocker motion. The next factor is as MAVOWAR said---- the spring bind and rail rockers contacting the spring retainers.
