Originally Posted by Matt1981CJ7
I don't think tweaking the timing a little during break-in hurts a thing. My dyno guys did a bunch of that.
I agree. You always seem to have to crank it one way or the other to get it to fire. That's normal.
My point earlier is that, once it does fire, you'd throw a light on it to make sure you had plenty of timing in the engine to keep the temp from going stupid on you. Have the light hooked up and safely out of the way. Go straight to over 2k rpm and check to see if it's at least 40 degrees and rotate the distributor accordingly.
The mistake during initial fire-up would be to idle it while you set it at 10 degrees or something.
I have an old friend that installed a numbers-matching, rebuilt 283? in a gorgeously restored '58 Corvette a year or so ago. I asked him how the initial fire-up went because he didn't build the engine.
He told me that he fired it up and simply set the idle speed and initial timing. All that was left to do was "break in the cam".
He had no idea (and I didn't have the heart to tell him) that he just killed about 90% of that cams ability to survive the first 500 miles.
You still might get lucky and need a 7.8 inch push rod. I know a guy... lol