what do you order or do when looking for motor mounts for a 1967 firebird and you have a 1975 block is there a special mount

It depends on how many holes your block has. You may be able to use the stock 67 mounts if you have a 'five hole' block. Five thread holes for motor mounts on each side. How many you got?

looks like 3 holes in motor mount on the block side

Oh! Suddenly one can bolt up a new style block to old style mounts. And some people have been doing it while others were riding their big wheels. Amazing what can be uncovered when can take a moment and listen. The only thing that remains is can old style blocks mount to new style mounts?

Ah but we have a prime example in our grips. Merv, you have been preaching for years that they ALL can take a standard mount. This 1975 block. The owner says it has 3 holes for the motor mount. I ask you Merv, what are the chances that those three holes will line up for stock 1st gen mount?

With a 1975 block that only has three holes for motor mount bolts you will need an adaptor kit. I'll look around and see if I can find an example.

OK Classic Industries has this part;
Pontiac Engine Conversion Brackets-Late Eng. Into 1st Gen.
This kit facilitates the use of a 1970-81 Pontiac engine in 1967-69 Pontiac F-Body chasis. Due to a 3-bolt mounting configuration on 1970-81 Pontiac engine blocks, an adapter bracket becomes necessary for proper engine positioning. This 2 piece conversion bracket set converts 3-hole motor mount pad on a block to 2-hole mounting.
C269514 70-81 engine into 67-69 Pontiac F-Body $69.95 pr.

That is verbatim from the catalog. I've run into a few of these 3-hole blocks. I've also been lucky enough to find some that had 5 holes to accomodate either style mount. You could make your own brackets but it take some time and measuring if you haven't done it before.

i only have the mounts on the block i have to order the mounts for the crossmember so should i order the original 67 mounts or the 75 mounts..the mounts on the block have 3 holes and 1 big bolt thru the center to conect to the mount on the crossmember Thanks

Make sure that there aren't a couple extra holes on the side of the block to accomodate the old mounts. Wouldn't want to steer you in the wrong direction. If not, you buy the older mounts and the adapter plates.

Is ZPH at it again Jim?

(panting heavily) Thanks guys for the panic attack. I just blazed my way into the garage to check my bare '72 YA 455 block and am happy to report I have 5 mounting holes on each side - all threaded.

If you have a three hole it's not that bad. Really.

3 holes on my 455 the motor is om a stand nothing painted over block casting is 500813so i guess ill order the 67 mounts with adapter plate thanks jim

thanks jim order from classic industries

I have an idea. If you could give us the 'specs' on those plates when you get them some could make their own when this problem arises. The way I did mine was to bolt a plate to the block on either side. Bolt the mounts to the frame mounts. Sit the engine were I wanted it and then welded the motor mounts to the plates. I didn't get any measurements because I did it this way. Those plates you are buying will have four holes. Two threaded and two bigger. They should be easy enough to make with the hole locations mapped out.

OK Classic Industries has this part;
Pontiac Engine Conversion Brackets-Late Eng. Into 1st Gen.
This kit facilitates the use of a 1970-81 Pontiac engine in 1967-69 Pontiac F-Body chasis. Due to a 3-bolt mounting configuration on 1970-81 Pontiac engine blocks, an adapter bracket becomes necessary for proper engine positioning. This 2 piece conversion bracket set converts 3-hole motor mount pad on a block to 2-hole mounting.
C269514 70-81 engine into 67-69 Pontiac F-Body $69.95 pr.


i beg to differ on this very subject. i have a 72 block with 3 holes and used the stock 400 mounts with no alignment issues or problems!

I doubt it unless you show me a picture. A 72 block would have been made for a 72 car that has different style engine mounts. Three bolt holes doesn't accommodate both styles. Go back and check again Drew. Why else would they sell the kit?

and my 3 hole block will not bolt up to the 67 original mount so what can i tell you.it does not work

I thought the issue was when you wanted to put an early block in a later car. Then there weren't the right holes to fasten the later engine mounts to. I thought he later blocks have enough holes that a pair will fit the '68 mounts. I have a 71 engine that has '68 style two bolt motor mounts bolted on and it was in the car that way when I bought it. Nothing was rigged. Transmission mount was stock and there was nothing home made or welded to make it work.



This is a '71 engine, code E071 by the distributor?

We can all fine tune our knowledge with these testimonies. Willy has a 3 hole 75 block that the 1st gen mounts will not fit. I have seen these blocks too. So there are some out there. That's why there is a kit. Aaron has proven the theory wrong that it's all the three hole blocks that are the ones that the mounts do not fit. It makes it a little trickier in determining which ones need the adaptation. I believe it has something to do with the application and/or year whether the 3 hole blocks fit. One application that I remember that doesn't work without adapters is a 400 out of a 75 Grand Prix. The only post 1969 blocks that are going to accomodate the mounts without checking are the five hole mounts. One thing that is a given is that not all later blocks are a direct bolt in.

cant give a pic because the car is torn down to the shell at the moment but i can attest to this! it fit in perfectly and had just enough room for the harmonic balancer to turn! no extra but it fit!

also one example: just because a 81-88 cutlass supreme didnt come with a 455 engine, does that mean it wont fit? i know it will as ive had one in an 81 for some time but have pulled it and put a 350 chevy back in! anything will fit if you find the right factory parts gm designed to work for it!

Read the post above Andy.

we posted at the same time jim. ill try to get measurements of my block tomorrow for reference. maybe willy can do the same and see if we come up with the same to know if he needs the adaptor kit!