Hi to all and thanks to all that responded. Seems problem is solved - no more popping. First started by driving car immediately when cold. I thought that perhaps the fact that the chokes were still closed would affect SOMETHING . It didn't - the car popped immediately, just as before, as soon as I got to the traffic circle a few hundred feet down the road. Before starting on big work, like pulling the rams off, it seemed logical to try the easy stuff first. The solution? Replaced the distributor with another unit. Solved the problem completely - I cannot get the carbs to pop or sputter no matter if I turn left, or right, or whatever ! It was an instantaneous fix. Whew ! Why a distributor problem would make a car pop back thru the carbs on left hand turns is totally beyond me. Visual inspection of old distributor reveals nothing afoul. I intend to ship the distributor to Don Verity so he can set it up on his Sun distributor machine and hopefully find out what was wrong with it. Thanks again to all that responded . It all helped ! Maybe this can help diagnose Pete Fitch's 300G as well ! 300'ly to all