[2manyT/A'S]

Found this in the back of my shop today....

Pulled it out of a 72 Bonneville Hurse...about 20 years ago.....

It was a good running fairly low mile engine....so it might be time to do something with it...

455 2bbl......with small valve heads...it must have been a torque monster....

First things first......it's getting a BATH......a set of 6X-4's.....744 cam and a double roller TC.....think I have a 72 4bbl and intake here for it...

My question IS.....Will the alternator/PS pump/brackets fit under the closed hood of my 73 bird?

As you can see by the pics...it is a large case alternator...with NO A/C....and there does NOT appear to have been an idler pulley.....as I usually see with the large case alts...

Any input is appreciated....

[77 TRASHCAN]

Curious what heads are on it now???
I have the remains of a 72 Bbl engine, had the 7M5 heads I think the comp. ratio was 5:1...LOL

[2manyT/A'S]

Originally Posted by 77 TRASHCAN

Curious what heads are on it now???
I have the remains of a 72 Bbl engine, had the 7M5 heads I think the comp. ratio was 5:1...LOL

I'm pretty sure they are the original ones still.....I looked at most of the #'s back in the day...

Will confirm later...

[Ben M.]

Originally Posted by 2manyT/A'S

and there does NOT appear to have been an idler pulley.....as I usually see with the large case alts...

Only on F-bodies, to clear the hood. Big cars (and I believe A-bodies as well) didn't use the idler pulley setup. Large case was for the rear defroster (80A), regardless of AC. Get a standard set of '71-79 brackets for a non-defrost car, done.

The larger alternator front bracket and power steering front bracket I believe are the same, but the rear power steering bracket is not and the intermediate brace for the 80A alternator to mount to gets removed. Best to just get a complete set rather than worry about piecing something together.

[rexs73gto]

It will fit , if you look at the engine you'll see that the alt. doesn't set any higher then the air cleaner, so yes it will fit no problems.

[2manyT/A'S]

Originally Posted by rexs73gto

It will fit , if you look at the engine you'll see that the alt. doesn't set any higher then the air cleaner, so yes it will fit no problems.

But that's a B body air cleaner........A and B body AF housings sit higher on the carb than F-cars did...in those years...

[2manyT/A'S]

Originally Posted by Ben M.

Only on F-bodies, to clear the hood. Big cars (and I believe A-bodies as well) didn't use the idler pulley setup. Large case was for the rear defroster (80A), regardless of AC. Get a standard set of '71-79 brackets for a non-defrost car, done.

The larger alternator front bracket and power steering front bracket I believe are the same, but the rear power steering bracket is not and the intermediate brace for the 80A alternator to mount to gets removed. Best to just get a complete set rather than worry about piecing something together.

That's what I was thinking.......sure I have a set stashed here somewhere.

Crank and WP pulley should be the same for a non-AC car...

['ol Pinion head]

Before I owned my '72 TA, one of the prev owners, had removed the idler pulley setup, and at one time had mounted an adjustable 80 amp alt mting PLATE for the 80 amp alternator. From evidence on the bracing of the original hood, as the engine torqued over the 80 amp alt case had rubbed against the hood brace. This bugged me, and from parts books and examining a friends SD T/A, educated myself that the complete correct idler pulley/fixed alt setup was what I needed. Even though for what ended up being more than 15 years I was out in well stocked bone yards, several days a week, it still took me several years to come up with the correct idler pulley bracket/set-up, and Firebird front alt mtg plate. That frustration led me in the early 90's to begin buying gobs of '80 amp Pontiac only mounting parts and when I could find them, also, nice "1015" and "1016" alt cores. During this time, also began pulling "138" and early "296" water pump cores to rebuild...sorry, I digress.

During this time began restoring several '71's and '72's with the normal 37-55 10SI alternator. There are differences in the mtg PLATES, between 10SI mounting and 27SI. Thise differences include:

-front alt PLATE
-rear alt bracket that mounts to the intake (often missing)
-small front PLATE that mounts to the PS pump.

Would have to double ck if any machined spacer is different on the PS pump.

All these '71 up 10SI mtg parts shouldn't be that hard to come up with, and I agree changing to 10SI would be the wise thing to do. Hope this helps with mounting the '72 engine.

[thepontiacman]

72 455 2bbl heads were 7L4 castings.