it depends on the spings and pistons not the heads them self. its very technical to explain, but basicly you have to make sure the sping doesnt bind at full lift. also the spring has to be strong enough for the cam. the more agressive the cam the stronger the spring has to be. most cams have a recomened spring kit for them. also you have to make sure that the valves dont hit the pistons.
With pressed in studs, they are the limiting factor here, not the gross valve lift and piston to valve clearance. Any cam more than about a Comp 268H will pull the studs out, from the rocker motion generated by the cam profile.
great info guyskeep it coming. what i have right now towards my build is a bone stock 68 302 block/heads,crank,rods,pistons,that cam,1.7 comp cams roller rockers.i do have a pr. of e7te heads with screw in studs and double springs,but don't know the specs on the springs.i just can't seem to find any info or a "recipe" to do a decent build without getting too exotic,and not brake the bank.
i have this cam in my car. i have triple springs, 7/16 screw in studs, push rod guides, comp magnum black chromeoly push rods, and 1.6 roller rockers which increases my cam size and my heads are shaved. this site also tells you recommended hardware for there cams and it has installation notes http://www.compcams.com/Cam_Specs/CamDetails.aspx?csid=795&sb=1
Take those E7's to an auto machine shop and there, they can remove a couple and check the spring rates. They should have a little press looking tool there that measures the spring rate. And don't think that you have to choose a cam that requires the exact spring rate you come up with. It doesn't have to be dead on, just in the general neighborhood, like plus or minus 20-30 lbs open and closed. If you're running a flat tappet grind, then the rates need to be closer, especially on the upper side. More spring pressure = shorter lifter life, but at the same time this gives you a higher rev potential.
1.6 rockers do not increase the cam's "size" 1.6 is the stock ratio. The rollers will tighten up the lift specs simply due to their lesser tendency toward deflection (they're stiffer than the stock stamped steel rockers)
Thats a nice cam to build a car around. My first MAv had a pretty serious 302 in it. I knew what my goal for the car was so we picked out a cam and built the whole car and drivetrain around that camshaft. Of course now I'm a bit older and wiser I guaranteee the cam choice would be little more streetable.
thats basically what i want to do with my mav.a weekend warrior and see a little track time.just some seat of the pants fun.i'm trying to find the best way to do some sort of combo,without actually doing a stroker.
Not considering the stud issues, I believe the physical limits is around .500 lift before you get coil bind or have to cut the valve seal seats down.
i can't remember where i read it,but the stock springs supposed to be able to handle 500 lift.not sure if i believe that though.
Not to sure the exact limit but a friend of mine had good results running 460 lift with stock springs and pressed studs on a 65 289. every thing worked great for a few years untill a bearing spun.... but the springs and studs were not to blame for that Just my $0.02 M
I just buttoned up my 302. My machiniest recomended grind#268H from Comp. cams. It has 456 intake & exahaust lifts. I'm running 69 heads with 54cc combustion chambers, with flattop pistons. He also said with factory heads, to keep the lift below .500. Does anyone else have this cam? How does it run? I bought this as a kit. it came with lifters,springs& retainers. And I have pressed in studs.
