Will the thm425 fwd transmission bolt in place of a thm400 on Chevy small block?
No, the THM425 FWD transmission will not bolt in place of a THM400 on a Chevy small block. The THM425 FWD transmission is designed to be used in front-wheel drive vehicles, while the THM400 is designed for use in rear-wheel drive vehicles. The THM425 FWD transmission has different mounting points and different input and output shaft lengths than the THM400, so it is not possible to bolt it in place of a THM400.