My suggestion would be to replace that RPM cam. Edelbrock doesn't make any cams, they just relabel someone else's. They are more hype than anything else.
What's your "stock bottom end" built of ? If you've got a stock 73 bottom end, then probably the best cam choice would be a Comp 268H. This will take advantage of the 8 to 1 comp ratio. Which is probably less than that now with those E6 heads in place of the 73 heads.(you added 10 cc's volume to the compressed volume) If that's the case, then you comp ratio is down close to the 7 mark. And even lower with the Edlbrock cam in the dynamic compression.
The rotating assembly is actually stock for a 1968 302. I think they have a little less dish in the pistons than later ones, giving me a slightly better CR maybe.
The RPM cam is fine, just possibly needs a compression boost. You lost a full point in using those E6 heads. You went from the 68's 9.5 to 1 down to around 8.5 to 1. That cam probably needs from a 9-10 to 1 to work properly. It's pretty close in specs to Crane's Powermax (363801)
Yep, first step here is to figure (measure) what your actual compression ratio is. Preferably each cylinder 'cause they can vary. Many get very optimistic here and guess much higher CR than they really are at. Larger duration the cam the more compression you need. Every Edelbrock cam I've checked has very lazy ramps compared to most performance cams. The max lift and duration @ .050" doesn't tell the whole story. I've read where numerous engine builders/tuners gain 20 - 50 hp just by ditching their customer's Edelbrock cam and sticking in a comparable Comp or Isky piece. A few years ago I ran an Edelbrock RPM "Rolling Thunder" roller cam that was supposed to match my heads and intake. Sounded good but performance sucked. Installed a milder Comp cam and the difference has been unbelievable, in a good way. You gotta know where you are in order to figure what direction to take to get to where you want to go.
