700r4,th350,th400 all bolt to 454 big block? - Third Generation F-Body Message Boards

89importeater · 07-25-2007, 09:41 PM

i have been thinking about doing a big block swap for a while. whenever i finish painting my car i will start on the motor so i figured that if i could find a big block before then i would build it or if not i would make a 383 with a 350 i have now. well i may have stumbled upon a 454 even though i wasnt really looking for one but i just want to make sure that a 700r4,th350, and th400 will all bolt up to a big block. not sure at to what transmission i want to use yet so just asking. I've read most of the posts that are big block swap related but dont remember seeing anything about transmissions.

AlkyIROC · 07-25-2007, 10:23 PM

You need a flex plate specific for a 454 because it's externally balanced. The 700R4 and TH350 bolt on identically. The TH400 torque converter has a different bolt pattern on the torque converter but most aftermarket flexplates have a dual bolt pattern to fit the TH350/Th400 torque converters.

A TH350 converter will fit on a TH400