Help with cam selection/valve clerance

[mustang2422]

Well the problem I have is Im not sure how big a cam I can use in my motor. I have an 1986 5.0 roller motor.This motor has the flat top pistons with no valve releve. I would like to get any of the motorsports 303 cams but I would hate to buy one and be to big.
Any one have any experiance with this motor and how big of a cam I can use ? Thanks to any one that can help.
Aaron

[boosted331]

Save the money you would have spent on a junk alphabet cam and invest it in a set of good heads. Your stock heads flow like crap, adding a big cam doesn't do much to make more power when the heads still flow like crap. A set of bolted on AFR 165's or some TW's will add a boatload more power all over the powerband, and still have OEM driveability.

[motor_head_429]

The question is not really how big a cam you can run, but what cam would work well with your particular combination. If you have stock heads and exhaust, then an e-cam won't do much for you. If you just want more lift then just get 1.6 roller rockers instead of the cam, that will also free up some horsepower from the decrease in friction. In any case, the e-cam should not make the valves slap the pistons, at least not with 1.5 or 1.6 rocker arms.

[GTStang]

86 is a bad year...... The flat-top pistons make using any aftermarket head or cam that is worth the time and money impossible w/o flycutting the stock pistons which at that point you might as well change for new slugs. I would seriously consider using the money to get new slugs so you can use a H/C set-up that will actually be worth the time and money.

[351wStang]

Some 9.5-10:1's with the Performer RPM heads, hydro roller cam, and the newer Performer RPM II intake would make your car a screamer on the streets with a 5 spd and 3.73's.