New cam and heads for original 273?

The 302 heads are good, but watch for the high spot that hits the driver side exhaust manifold near the #7 cylinder. I broke 2 stock early A exhaust manifolds not realizing the heads have a high spot that needed to be carefully ground down in order for the manifold to fit properly. I have the 302 heads and a crane 268 cam in my 318 and with an edlebrock 4601 carb and performer intake. I really like the lopy idle I get. Good power. In fact my 2 year old clutch cant really handle it. I am going with a stage 3 or 4 clutch and maybe an hydraulic throwout bearing pretty soon. Too much slipping when trying to do a burnout..