Quote:
Originally Posted by kdeman1@yahoo.com
I took a video and let’s see whatcha think! 
Looks okay to me! I video’d both |
I agree that side looks fine, I presume the other side looks the same.
I did use a flat tappet cam and, at that time, Rotella T oil for the zinc properties. Now I use Valvoline VR1 20w50 conventional for the same reason.
Usually "popping" (backfire) thru the carb is an ignition issue and thru the exhaust is a fuel issue. Perhaps that can narrow it down for ya.
Long ago I had a very fine crack in the dist cap of a '77 301 that could not be seen, but showed up on a distributor machine. But I think that didn't allow the engine to start if I remember correctly. If you have an old school shop around with a machine, I'd remove the dist and get it tested. At least that would eliminate or confirm an ignition issue.
Also do you have a stock Pontiac style cam and wires hooked up in proper firing order? I once had just bought a good running '69 Mustang 351W and unbeknown to me it had an aftermarket cam. I did a tune up on it and it fired right up and idled fine, but would not rev up. After checking and double checking my firing order I decide to start pulling wires on the running engine. I wound up with an idling engine on four cylinders! So one by one I touched a wire to a plug. If no difference I'd put it to a different plug until the idle speed increased. After getting all hooked up, I wrote down the firing order and it was a 302 order. Now puzzled as I knew it was a 351W, I discovered aftermarket cams use a 302 firing order!
I hope something here can help you out.