The T&J Guide indicates that the factory dist. vacuum advance should be stamped with 439 12 on the bracket. Would a service replacemnet part # 1973436 be stamped with the same numbers? Thanks
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Re: LS6 vacuum advance can
Bernie;
Sounds like were both after the same thing. That was exactly my question, hoping to get an answere from Joe Lucia. -
Re: LS6 vacuum advance can
Warren and Bernie-----
The vacuum control used for 1971 LS-6 applications was GM #1973439. The unit is stamped as the judging guide describes. This piece was discontinued without supercession in October, 1979. This unit required 7 inches of vacuum to start the plunger and produced 12 crankshaft degrees of advance at 12 inches vacuum.
The GM #1973436 vacuum control was used for 1971 LS-5, as well as other applications. It would have been stamped "436 17" (I'm not 100% sure about the 17, though). This unit was available from GM until December, 2005. However, the part sold for the past 14 years, or so, DID NOT have markings on it like the originals. Basically, these units were aftermarket units packaged in Delco boxes. The 1973436 control required 8 inches of vacuum to start the plunger and produced 20 crankshaft degrees of advance at 17 inches vacuum. So, you can see that the 1973439 and the 1973436 are in no way similar in their characteristics.In Appreciation of John HinckleyComment
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Re: LS6 vacuum advance can
Joe: I am sorry. In the original meesage, I typed 1973436 instead of 1973439. Based on your comments concerning the LS5 units (original factory vs service replacement), I will assume that the 1973439 service replacement unit would not have the same markings as the factory originals. Do you know what application would use a "357 20"? Thanks, BernieComment
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Re: LS6 vacuum advance can
Bernie-----
The SERVICE replacements for the GM #1973439 had exactly the same markings as the original units----"439 12". That's because this item "died" before the change was made to the "generic" replacements. Consequently, the 1973439 never "suffered the indignity" as some of the other vacuum control part numbers, like the 1973436, which "lived on" after the change to aftermarket parts was made in the early 1990's.
The GM #1115357 was used for MANY Chevrolet applications. As far as Corvettes go it was primarily used for 1965-1970 250 and 300 hp small blocks.In Appreciation of John HinckleyComment
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Re: LS6 vacuum advance can
Thanks Joe, looks like the ebay one, had an incorrect part put in the wrong box! I guess we both will continue looking.Comment
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Re: LS6 vacuum advance can
Hum, I'm holding a reconditioned (fresh cad plating) '436' vac advance in my hands and it's stamped '436 20'. I think Joe said it should be stamped '436 17'... Does that mean there were two versions of the part?Comment
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Re: LS6 vacuum advance can
I just looked at my "436" can and it is also stamped "436 20. The TIMJG calls for "436 16". Seems be some confusion here.Comment
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Re: LS6 vacuum advance can
I have two 436 cans both "20". Will probaby be revised in next revision of T&JComment
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