Please bring me up-to-speed about the GM flexplate adapter. [part number of spacer & bolts] So that a powerglide and SFI flexplate can be installed.

Also, what is being used in reference to starters? Is the Delco starter capable of starting a 12.1 compression 370 CI [4.030 x 3.622] or, is an aftermarket starter a better choice?

 

You'lle get a better response by posting in the Automatic Transmission section. Maybe contact FLT as well. They build transmissions.

 

Power Masters has a nice starter that is clockable so that it can fit different header combos. TCI makes a flex plate and spacer for older style trannies, I'm not sure about a power glide.

 

I also believe that some converter manufacturers are making converters for older transmission that eliminate the need for an adapter and have the proper bolt patter for the LS flexplate.

Andrew