Hi, Algershick. I was going to PM but decided to open a topic so all could benefit. I love the '67 Pontiac 400 in a G-body idea! But be careful, the mounting bolt holes on the side of the block may not be correct in a G-body. Up to 1970 Pontiac used two mounting bolt holes on each side. After 1970 they used three holes for a different type engine mount. Blocks made between 1970 and 1976 had five holes so that blocks could be used in both the new and old models. 1977 to 1981 only had the three holes and are what our cars came with. Here is an article I cut from this site: http://pontiachunters.com/articles/pontiac-engine-block-identification/http://pontiachunters.com/articles/pontiac-engine-block-identification/
"In 1970, all blocks now had (5) motor mount holes, but not always tapped. The additional holes were done to fit the 2nd generation Firebird/Trans Am frame. The last of the V8’s (1977 to 1979) did not have the rear motor mount holes at all. Making it very difficult to install in to a GTO/Tempest.
1959-1969 Blocks have only (2) motor mount holes on each side of the block (see #2 & #5). These blocks will fit any 1964-1974 Pontiac A-body except cars originally equipped with a 455, which used a 3-bolt style mount. Later cars with 3-bolt motor mounts can be adapted to fit this block using a Butler Performance WRP-MM6 or Ames Performance N24CCA adapter kit.
1970-1976 Blocks have all (5) bolts holes (see above) but were not always tapped. The additional holes were done to fit the 2nd generation Firebird/Trans Am frame. These blocks are very interchangeable and will fit any 1959-1979 Pontiac V8 motor mounts.
1977-1979 Blocks have only (3) motor mount holes (see #1, 3 & 4), but can be adapted to fit earlier cars that originally used a 3-bolt mount by using the Butler Performance WRP-MM5 or Ames Performance N24CC adapter kit."
The adapters are available but not a perfect fit so expect some swearing when installing. Another thing is the fact that in '67 high compression was the rule. You may need a swap to low compression heads to use the motor with today's crummy gas. Good luck and post your progress as I'm sure we all want to see how this turns out!
"In 1970, all blocks now had (5) motor mount holes, but not always tapped. The additional holes were done to fit the 2nd generation Firebird/Trans Am frame. The last of the V8’s (1977 to 1979) did not have the rear motor mount holes at all. Making it very difficult to install in to a GTO/Tempest.
1959-1969 Blocks have only (2) motor mount holes on each side of the block (see #2 & #5). These blocks will fit any 1964-1974 Pontiac A-body except cars originally equipped with a 455, which used a 3-bolt style mount. Later cars with 3-bolt motor mounts can be adapted to fit this block using a Butler Performance WRP-MM6 or Ames Performance N24CCA adapter kit.
1970-1976 Blocks have all (5) bolts holes (see above) but were not always tapped. The additional holes were done to fit the 2nd generation Firebird/Trans Am frame. These blocks are very interchangeable and will fit any 1959-1979 Pontiac V8 motor mounts.
1977-1979 Blocks have only (3) motor mount holes (see #1, 3 & 4), but can be adapted to fit earlier cars that originally used a 3-bolt mount by using the Butler Performance WRP-MM5 or Ames Performance N24CC adapter kit."
The adapters are available but not a perfect fit so expect some swearing when installing. Another thing is the fact that in '67 high compression was the rule. You may need a swap to low compression heads to use the motor with today's crummy gas. Good luck and post your progress as I'm sure we all want to see how this turns out!