Will a Pontiac TH400 Transmission fit a TH350?

[sdkar]

Hey guys,

There is a 71 Pontiac Grandville at the junkyard near me and it has a TH400.  Will this fit in place of a TH350?  What modifications will be needed?  I anyone interested in buying this transmission if I get it and I am unable to use it?

Thanks,

Steve

[JohnZ]

Physically it should fit (the THM400 was used on big-block Camaros), but I'm not sure the Pontiac trans is the same length as the one used in the Camaro, and the Pontiac trans MAY have a different case bolt pattern than the Chevy trans where it attaches to the engine block. Someone more familiar with Pontiacs than I am will have to answer that.

[Sauron327]

  *That tranny is longer. The tailshaft housing would have to be changed and that means changing the mainshaft. Our Camaros require a shortshaft 400.
  *Some Pontiac trannys have multiple application mounting holes. Others will not fit your Chevy block.  Exactly which P. trannys will bolt up to the Chevy block I am unsure but the length alone will not be applicable for your requirements.

[CNorton]

Pontiac TH400 has a BOP (Buick, Olds, Pontiac) bellhousing bolt pattern.  It doesn't match a  Chevy.

[sdkar]

Thanks for the info.  The Junkyard wants $75 for it and I thought if I couldn't use it that I could pass it along for what I paid.  However, I think shipping could be prohibitive.  It does have the longer tailshaft, which means it also has the longer shaft as well, so it would involve more than a simple tail swap.  Good price for a TH400, but obviously the right one.

[Fastorange]

  I also think that the mounting holes are in diffrent spots.