35 A jd troubles again

A wise guy might just say you've got a crowd pleaser. Something spectacular to see at night.

But you'd better get that deal fixed before you damage the exhaust valves. The stock ones don't like all that heat.

Normally if the flame that should be pushing the piston down the cylinder is coming out the exhaust instead either your spark plug is firing way too late -- near the time the exhaust valve is opening, or your exhaust valve is opening way too early and letting out the explosion that should be pushing on the piston. Either way, it's a timing problem of some sort and it could do some real damage to the engine. Check the ignition timing and the valve lash and timing. When the big overbore was getting done, was there a real long duration cam slipped in there? This sounds like the kind of cam duration setup you'd see at a drag race track.