i have a 78 cdv with an pre 74 stock 472 in it. this week, it has started stumbling when it gets hot and runs better when cold. it has a full tune-up, a rebuilt 800cfm electric choke q-jet carb, set it to where it pulls 18-20 in. of vacuum so that looks good. the gap on the plugs are good. has an points style dist. with electronic conversion, stock coil and condensers. it's really hard to start in the morning also. could this be an engine problem itself. haven't done a compression test yet. haven't checked the timing either. all the plugs are brownish so that looks good. can't figure this one out!