ayear or two ago i got the bright idea to change my belts and get "smaller" by applying 307 hardware to my 71-455.
I only have about 5k on the motor and the other day i got this squealing noise. Things had been good till now.
i did have problems when mounting the power steering pump and alternator brackets. I made a spacer to go between the two brackets and to tie them together. It took many tries but i managed to get it all together.
It seemed that not only was the block taller but the mounting positions of the mounting bosses on the block were possibly different. never the less i managed to shim it up and viola! it worked for the time being.
I recently put a new water pump on because of the squeaking that manifested. That didn't cure it so i reluctantly replaced the powersteering pump and thought for amoment that it was fixed. but at fast high revs above 2800 to 3500 rpms the darn thing squeals like a pig.
My thoughts were that the 307 bracketry was going to work without a hitch and the belts would be shorter. Now I am wondering if this was a no win situation.
Any tips on how to eliminate the 1971 mile long brackets and the extra 40 pounds of cast iron mounting hardware that normally is on the 71 455?
HELP!
by the way the PS pump and the WP are both off the 84 307. I have yet to install the AC from the 307 for lack of time and elongation of the bracket is necessary.

 

Yes, the big block Olds has a taller deck height than the small block. The PS pump brackets are essentially the same for 1968-1990 motors. The mounting points on the blocks are the same (except for the deck height difference). The spacer between the PS pump and the alternator bracket needs to be about 1" when using 307 brackets on a BBO. Have you properly installed the two spacers that go between the PS pump bracket and the block? One goes on the bottom front threaded stud and one goes between the lower rear bracket and the side of the block.

 

Thank you for the insight.
i am indeed missing the spacer between the bottom of the bracket for the PS and the block.
Can you tell me how thick a spacer that it needs to be?
I have tried everything from pulling the top waterpump threaded bolt and placing th pulley behind it and then running it back in. I fell like a caged cat trying all kinds of stupid things that have yet to yeild anything fruitful other that the experience of knowing righty-tighty lefty loosey.
Duh!
So let me ask you then. Are you saying that i shouldn't be having this much problems with the 307 brackets on my 455?
Is it a feasable thing?
I feel like Gary Moore; Jumpin' at Shadows.

 

Many people have used the 307 brackets on a 455. The two changes are the spacer between the PS pump bracket and alternator bracket that you've noted and the need to weld extensions to the two bottom bolt holes on the A/C compressor bracket if you are running A/C. Otherwise, everything bolts up. Of course, the taller deck height means that you need LONGER fan belts.

The spacer that goes between the pump bracket and the side of the block is roughly 3/4" thick. In a pinch, I've used a large nut that was able to slide over the bolt. Also, once the brackets are properly installed, be sure you are correctly tightening the PS pump belt. There are three fasteners that need to be loosened on the pump, two bolts behind the pulley and the nut at the lower rear. Once loose, insert a large screwdriver or pry bar behind the pulley, between the nose of the pump and the tab that's part of the front bracket. This tab is on the inboard side of the pump nose. Now you can use the screwdriver for leverage while you tighten the three fasteners.