What should I look for to distiguish a 1965 BB lower alternator bracket from the 1966 bracket? Are they both cast iron? Thank you. Steve
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No droop in arm to rear bolt; no cast #
The '65 L78 part is #3863138; the number does not appear on the bracket. The '66-69 (?) lower alt brkt (w/o P.S.) is part #3882810, and this # is cast on one of the webs. The 396 bracket is designed for the alternator belt to lie in the rearmost groove of the crank and w.pump pulley; the '66+ is the forward groove.
Of course, 99% of the eBay brackets are for '66+.
I will post a pic tomorrow morning showing the differences in the arm geometry (I understand GM raised the design of the arm then added the droop in order to allow for the new Air Injection Reactor tubes. -
Re: No droop in arm to rear bolt; no cast #
On "the bay" I've seen PN 3878264 also described to fit the same applications as 3882810. Any idea what the difference is if any? Thanks for the info, that helps a lot and if you have a chance to post those pics, that would be super.
Thank you,
SteveComment
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Re: No droop in arm to rear bolt; no cast #
Steve-----
GM #3878264 was an alternator bracket used for most 1966-67 passenger cars with 396 or 427. As far as I know, it is not interchangeable with the 3882810 Corvette-only bracket.
GM PART #3878264 was discontinued in January, 1968 and replaced by GM #3919884 and, shortly thereafter, GM #3925526. The latter were the PRODUCTION brackets for 1968 passenger cars with big block, but I THINK they carried the 3878264 casting/part number. The 3925526 was discontinued without supercession in August, 1984.
The GM #3882810 Corvette-only bracket was available in SERVICE until just a few years ago.In Appreciation of John HinckleyComment
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1990 NCRS Cypress price puts eBay to shame
Don't know if this ever sold.
Link below to compare an L78 bracket (top), and [from what Joe L. has described] probably one of the '66+ 396 or 427 passenger car brackets. There are no part #'s on either. Notice the raised arm on the '66+ that drops to the head bolt, providing more clearance around the #1 cylinder exhaust.
note that both are designed for the alternator belt in the 1st water pump / crank pulley groove (from the motor). The bottom bracket could therefore be used as a "poor-boy" L78 alternative.
The "810" Corvette '66-'69 (?) bracket has the eyelets for the alternator mount moved forward to the #2 pulley grooves.
Notice the casting marks "E" in a triangle, the mould # in the web, The "G.M.", and on the backside of the web/arm there's a small "G" in a circle.Comment
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Re: 1990 NCRS Cypress price puts eBay to shame
That is a great help, thank you for taking the time. And also thank you Joe for your response. I do believe that now I can accurately ID the correct bracket for the car. As far as that price goes, that is premium I agree, but I've been so "desensitized" to outrageous prices through ebay all these years that I suppose I'm used to it.
SteveComment
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