It does not look like the 71 455 engine mount will work on my 69 firebird subframe.This is what the part on the block looks like.The part that mounts to the subframe looks way too big and has 4 bolt holes, I forgot to take a picture of it.
I think I figured it out, I need to find my frame mounts, the engine mounts in the pic wont work from what I have seen.
I think you need the rubber engines mounts on engine and the metal brackets on the frame like the 71 Firebird with the 455 .
I have a '68 Firebird with a '70 Grand Prix 455 block installed on the original '68 mounts, engine and subframe. If you do have a '71 block, it will probably have the holes, tapped or not, in all five possible mount locations. Mine was, and it bolted right up with no issues simply by using the original firebird mounts on the engine, and the subframe, just in the Firebird positions, which were not the same holes necessarily used in the A and B body Pontiacs. Don't forget the subframe mounts have an additional brace piece.I understand that the '70 and later early '70's blocks are the one's most frequently found with all 5 mount positions at least drilled in the blocks, and the holes can be tapped if they are not already. I hope you have all the original Firebird mount pieces and remember where they go. They are different from the block pieces shown in your photo, but they should bolt up pretty easily to a '71 block.There is a fairly flat plate that bolts to the block, the rubber mount is below that, and the bolt from the rubber mount goes through the frame mount, which is braced by a second bolt on piece, at least on the '68.Good Luck!
"Wherever you go, there you are."..Buckaroo Banzai, 1984
use the 69 firebird motor mounts on the 455. rubber 2 bolts to block 1 bolt for steel brackets on frame.
76 455/4spd TRANS AM69 GRAND PRIX 455/5SPD
Thanks, I did find my original mounts everything but the bolts, I will put new engine mounts on the block.