mopman93

I've got a cam with .493 intake lift and .510 exhaust lift. I also have 1.7 rockers. will this clear stock pistons? I also have a set of gt 40 heads. what size rockers shoulld i use and what would i have to do to use those heads with the cam?

RNGIII

Your total lift shouldn't affect piston to valve clearance at all. At peak lift the cylinder is at the bottom of its stroke. What you'll be concerned with is the opening and closing events of the valves as well as the ramp rates on the cam. Do you have any other specs on the cam? And, in all honesty, the best way to know is to check it with either a drop valve technique or a clay mock up. There are so many other variables, piston depth in the hole, gasket thickness, chamber size...etc. that affect that from motor to motor. Is the motor in the car?

mopman93

the motor is in the car and here are all the cam specs:
duration- 279 int 289 exh
cam lift- .308 int .319 exh
valve lift-.493 int .510 exh
will this work even tho the car has 1.7 rockers? and what rockers should i use with this cam and the gt 40 heads?

P Zero

You wont have any piston to valve clearance issues. I ran a similar cam in my old '79, mine was .496/.510 , 280*/292*. This cam ROCKED, it made TONS of torque, so much it ripped the rearend off of the car. I used stock 302 heads (they were milled .030 I believe) and rockers (1.6). You can even run a E303 which is something like .533 lift without any issues.
-P.

mopman93

wow now ur scaring me lol so the whole combo is good even with the 1.7 rockers?

RNGIII

With 1.7's that cam is going to be .523 and .542 peak lift.

The reason I say check it is because I've personally dealt with bent valves because of duration. The cam had .512 lift and the heads had 2.02 valves. They weren't bent much because they still sealed and gave full compression but the motor ran like crap.Both Lunati and Edelbrock said that it would be fine. It wasn't. For 110% accuracy check it.Most likelyyou won't have any problems with a stock headed combo because the valves are so small. But, because of my personal experience, I always check P/V clearance.

Good choice on the cam BTW. Favoring the exhaust with stock head is always a good idea. Like mentioned, it'll be a torque monstor. Good luck and have fun!

P Zero

Yeah your setup should be rock solid.
LOL! Didnt mean to scare ya, the '79-82 foxes were made with thinner guage metal and had a thinner firewall than the 83-93 models. Thats why my '79 only weighed something rediculous like 2500lbs. ANd thats also the reason the torque box with teh LCA attached tore off of the floorboard, and put a nice 2" crack right above teh rear axle.
-P.
PS: Your car should be fine, But if you hear any creaking, popping or any other unusual noises from the rear, reinforce your torque boxes.

mopman93

sweet thanks guys ill post numbers when i fianlly throw all the parts in