cam break-in PROBLEMS
 

I put a 351W into my '68. It had 15000 miles since a rebuild when I got it. I installed an Edelbrock Performer cam, timing chain and gears and a Performer intake. This morning was the 30 min. initial start up to break in the cam. I turned it over first to build up some oil pressure. I started it on high idle and she purred like a kitten. About the 5 min. mark I heard a couple of random clunks and it began to run a little rougher. There was a few more random clunks and a couple of slightly louder ones at the 15 min. mark when I shut it down. Did a break a lobe? I followed Edelbrocks instructions to a tee. What should I do now (besides go for a beer)? Murray

I'd yank the valve covers and check for extreme, (and sometimes not so extreme), looseness in any of the rocker arms.
It's quite possible you are a lobe, (or more).
Don't know if you're running a solid lifter, or hydraulic, (you didn't state if I remember correctly), but either way, it's way possible to have 'lost a lobe' of two, either accidentally, or a poop occurs situation.
I highly recommend just running the outer springs during the cam break-in period. Run without the inner springs, for 30 minutes or so, and then shut everything down, install the inners, and re-fire engine.
The last cam we installed in last years motor, was installed in a different motor before that, and it ate a lobe in that application. Had the cam repaired, and installed it in my last years motor, and sure as hell, it ate one, (a different one), that time.
This years motor we ran just the outer springs for the said 30 minutes, then took her apart, and installed the inners for the dyno session. So far, so good.
In either case, good luck, and hope nothing too expensive 'went away' for ya.
Steve

drag79stang