So some info on the engine. 79 20R head been milled to make flat. EB Over sized valves and a mild port and polish,LC dual valve springs, LC adj cam gear and bigger cam 290.

81 22R block with dome pistons,all ARP's,MLS head gasket, everything else is OE replacements. I have a weber 38 on it also.

I can not get the engine to time right. it pings under a heavy load. I can pull 1st and 2nd with no issue 3rd and 4th ping under throttle. I have a LC pro Dizzy. I can't get it to line up to 0btdc with a timing light with out it dieing. So its set a 8btdc with out vac ad hooked up. Ive tried to move the dizzy a tooth back wont fire that way.

any idea's?

 

Did you degree the cam in? Make sure it isn't off a tooth.

Also, make sure the fuel octane is good for your compression ratio.