[bradkline]

I was dogged with this problem for years on my '66 Bonneville. Consider replacing the original ground straps with new ones. Despite shining them up with a wire brush etc. corrosion builds up under the crimp and you just don't get a good ground. Also make sure there's bare metal under the spot where they are bolted to the engine/firewall, a arm etc. I also replaced my battery cables which made my starter spin faster. I think what really solved my problem though was the fuseable link on the engine wiring harness. I routed a wire from the voltage regulator to the alternator bypassing the fuseable line and the problem was finally solved. I plan to add another fusable link in case of a short but I think you'll find your problem in one or more of these fixes.

Brad Kline