Trying to help a fellow NCRS member w/1962 300 HP. Do 250, 300 & 340 use the hollow stud @ left rear carb mounting for vacuum source? Do they all use the same length stud? AIM calls out a # 3749170 for the 300/340 application. OK, here's the rub - only 300 HP uses the phenolic (3/8+) spacer between the intake manifold and carb. Fellow member orders the hollow stud from C/C, but upon arrival, it seems too short to get the job done. And, I know you've all heard that before, but we are talking carburetors here - you know - important stuff. Thanks, DC
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Re: Help, 1962 LR Carb Stud...
Dennis------
Chevrolet specified the GM #3749170 stud for all 1962 Corvette applications except FI. The original stud was drilled for the vacuum take-off function and was 2-5/32" long. This would seem long enough, to me, for accomodating the 3/8" thick spacer, the carb base thickness, gasket thickness, and nut. I don't know if the current reproduction part meets this length spec, or not. Also, although I don't have the specs for the thread length on either end, it's possible that the thread length on the reproduction stud's 5/16-18 thread end (the end that goes into the manifold tapping) is too long, allowing the stud to thread too deeply into the manifold and, effectively, decreasing its available length for the rest of the job. 5/16" of thread engagement in the manifold should be all that is necessary; if the reproduction stud is engaging deeper than this, that could be the problem.
By my calculation, the length of the stud necessary for all retention functions should be close to 1-9/16". That would leave 19/32" for the vacuum connection, which would seem to be adequate.
By the way, and interestingly, although all 1962 Corvettes, including 300 hp but except FI, were supposed to have used the hollow rear stud, 1962 passenger cars with the same 300 hp engine DID NOT use this hollow stud.In Appreciation of John Hinckley -
Re: Help, 1962 LR Carb Stud...
Joe - Thanks once again for your superior knowledge. At least I own a 300 HP 1962 so I have some point of reference, and shall try to guide our NCRS friend in need whil'est refering to your knowledge base. If we do not speak sooner, please have a great holiday season - and a very, very sincere thanks from me for your INCREDIBLE input on this discussion board. Best regards, DennisComment
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Re: Help, 1962 LR Carb Stud...
Fellow members, my butt! You experimenting with another "concealed" portal of nitrous introduction to the poor 327? mikeComment
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Well, how absolutely rude...!!!
But now that you mention it, it would be a lot easier nitrous install than the one you falsely claim I did on the '57...Comment
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Challange???
Sounds as if a challange between "Dipstick" and the "Maryland Missle" could be in the future!!!Comment
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but...
The '62 340 HP used a dual point dist. without provision for a vacuum can, so why would it have used the hollow carb mounting stud.
DukeComment
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Re: but...
Duke: forgive the dipstick--recently had "fool" tatooed on his forehead. merry christmas.mikeComment
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Re: but...
'62 340's without vacuum advance used the hollow stud as the vacuum source for the windshield washers (became standard in 1961).Comment
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Re: but...
Hey, I'm really glad all you "old guys" are around to teach me about solid axle models.
DukueComment
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Re: Challange??? Ya know Gary...
It's so tempting to once again put the Maryland Missfire in his place. Hate it when you guys bait the trap. Usually takes a moderate bite out of the retirement fund - BUT, then again, historically, its been retirement fun...
Love racing a guy with a reaction time slower than the USPS. DipstickComment
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Re: but...
John: how do you suppose Dennis will inject Nitrous thru the hollow carb stud and at the same time generate vac. for the wipers?I can just see those trico blades react the nitrous boost. How about wipers red-lining at 7500RPM.Merry christmas, mikeComment
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Re: Challange??? Ya know Gary...
Have hired Dale Jarrett for reaction-time lessons. hear UPS does better than USPS.Merry christmas to your sorry ass and the most honorable and respected Sondra. How does she tolerate thou?mike and lea.Comment
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Re: Challange??? Ya know Gary...
Mikie - Now THAT is a mystery question. Best to you and your family. DipstickComment
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Re: but...
Mike-----
He's got it figured out. You never use NO2 in the rain, anyway.In Appreciation of John HinckleyComment
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