Alternator bracket

[Joe Weise]

Hello,

After purchasing my 1970 350/350 4-speed roadster, I've been going through it,
bringing it back to the correct , original condition. All of the after market parts have
been removed and replaced with the correct parts. After removing the headers and putting
on the correct exhaust manifolds, I had to buy the correct lower alternator bracket.

After install, I had to mount both brackets to the water pump. My top "curved" bracket
no longer clears the hump on the top of the alternator, not allowing me to mount the bracket
from the backside of alternator, only the front. Because of this, I had to add five or so washers between
the two brackets. Was or is there a different "curved" alternator bracket available that differs from the
one I already have?

Thanks.

Joe

[Jim T.]

Re: Alternator bracket

Replaced the original alternator bracket on my original owner 70 350/300 probably about 25 years ago. Bought the replacement from GM. Cannot remember if the original bracket fit over the alternator like you have mentioned, but do not think it did. My 70 has air and has the 61 amp alternator. Without consulting my parts book, they may all be the same. Anyway just looked at my 70 and confirmed that the bolt to secure the alternator is mounted from the front, the alternator bracket is in front of the alternator and not over the alternator. I have the invoice somewhere on the replacement alternator. Cannot remember for sure, but I think I can remember some difference in the replacement alternator bracket being a stronger built alternator bracket. If I had not moved 17 years ago, I know I would still have the original replaced bracket, it broke between the alternator adjustment securing bolt, just the top of the movement slot.

[Jim T.]

Re: Alternator bracket

Reviewing pictures in a Vette Vues Fact Book of the 68-72 Stingray second edition by M.F. Dobbins I saw a picture of a 69 350/350 and of a 70 350/300. The alternator adjustment bracket on both was over the top of the alternator with the mounting/adjustment bolt attached through the bracket to the alternator. The bracket is straight. The current alternator bracket I bought as a replacement is not straight, has a slight bend in it.

[Terry M.]

Re: Alternator bracket

Please check the AIM to verify what I am about to tell you.

The upper bracket should go behind (to the rear) of the tab or ear on the alternator. The bolt then enters the alternator from the back as well -- through a dark colored split lock washer on your 1970, then through a thick silver flat washer then through the adjusting brace.

If the curve of the adjusting brace doesn't allow this configuration either you have the wrong brace or perhaps are mounting it to the wrong water pump fastener. It should mount to a stud on the drivers side, in the upper hole of the water pump mounting flange. Again, the illustration in the AIM should help you sort this out more than my words.

I have seen several upper alternator brackets at swap meets, but I have no idea what fits what.

[Joe L.]

Re: Alternator bracket

Joe-----

I don't know which brace you currently have. However, the original brace for your application was GM #3881816. That brace was discontinued in September, 1975 and replaced by GM #361491 and 2 years later the 361491 was replaced by GM #460754.

Somewhere along the way about 1980, GM decided that the 460754 shouldn't be used for 68-74 350 applications and, instead, GM #3826928 should be used. GM #3826928 was originally used for early 60's passenger car applications.

In any event, the GM #3881816 had only a very slight offset of just over 1/4". The 361491 and 460754 have almost 1-1/4" offset. That much difference in offset is what changes the position of the brace relative to the bolt hole on the alternator. The GM #460754 is still available from GM, though.

The GM #3826928 is discontinued.

[Joe Weise]

Re: Alternator bracket

Thanks Gents.
I'll look into seeing if I can get my hands on the original style bracket.
The current one is mounted to the correct water pump bolt, near the top on the drivers side.
Just ask Patrick Hulst. He's seen it. I would say that 1 1/4" offset between the original style bracket
and the one I have makes all the difference. All those washers to align it just doesn't look good.

[Patrick H.]

Re: Alternator bracket

Joe,

We can compare your bracket with my cars and see how it matches.
I looked at pictures of your car from late summer, and it all fit before we ripped apart the front half of your car. So, we should be able to figure out how to make it work.

Patrick