Hello George,

Thanks for your reply. Why do you think the B21E Advance Curve would be better than the B21A Curve? While the Engines Blocks are the same, the Pistons are different, Compression Ratio is different, Heads are different, Camshafts are different, Spark Plugs are different, thus Timing settings are different. So, I would like to dig into your reasoning a bit more. I feel if the B21A Bosch JFU4 Distributor Centrifugal Flyweights, Springs, and Vacuum Advance are installed into the B21E JGFU4 Distributor, then the Advance Curve should be pretty close to B21A engine specs. I have graphical copies of both Advance Curves, for the B21A and B21E. They are significantly different. I feel if I use an incorrect advance curve then at best, the economy and perfomance may suffer, at worst, I may end up with detonation, which could damage the engine. Your thoughts or insights would be appreciated. I could e-mail you the two graphs for your analysis, if you like.