Guys,
I've acquired a car that currently has a BBC 468 and a Powerglide tranny with a 10" 4000 stall. Some are telling me that the 4000 stall won't be very streetable, and I tend to agree after a couple cruises around the block. The car has a tranny cooler, but I still worry abou the heat.

The previous owner removed the 8" 5000 stall and replaced with the 4000, but stated that it was the same converter as a TH350. He also mentioned having to have a new input shaft built for the 10" converter, which is where one of my questions comes in.

1.) If I move to a smaller rpm converter, do you have recommendations
2.) Not being an expert on automatic transmissions (I've always been a Muncie guy, but evidently this car went through three of those before they converted to the PG), the need to create a new shaft is confusing me. Could it be because the 8" converter had different splines/spacing?

Thanks for your help...