The trans is a bop th400 and im using an adapter plate to hook it to a small block chevy. I ordered a B&M 3000 stall converter from jegs the other day that said it'll fit any GM 1965-91 TH-400/425/375. Since it says GM i assumed it meant both BOP and Chevy cases. The converter thats in the bop trans is about 12 inches and the B&M 3000 stall is maybe 10 or 8, im not sure, but there is a significant difference there. I sold my chevy th350 but i thought it had about an 8/10 inch torque converter in it...or pretty close to the B&M one. Since the chevy case is smaller im sure thats the reason the converter is so much bigger in my bop but is it ok to run that smaller converter? Any help is greatly appreciated.