67 BB Vacuum Advance Help
I purchased a replacement distributor vacuum can for my 67 427/400 (without TI) car. The new can is a 360 12 from LI Corvette. The can that was on the car was corroded and I wanted a fresh cad look. The can I removed was marked 446 15. I was surprised to find this. I noticed a change in run quality with the new can. Although nothing significant. Can anyone help me determine what the 446 15 is from and could it indicate that I may have an incorrect replacement distributor. I'm debating whether to put the 446 15 back or purchase a replacement with the same number.
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Re: 67 BB Vacuum Advance Help
From Delco Remy Test Spec's DR-324S-2 1964-1976 supplement.
The 360-12 is correct for your 1111247 L68 distrib. The 446-15 is common on many in the 1974 era (1112247 '74 base engine Corvette, for instance).
The specs are quite similar: for the 201: 7-9"Hg to start advance; max adv @ 15-16"Hg; 8 deg max distr. adv. (ie. 16 crank degrees)
for the 446: 5-7"; 13-14"; and 7.5 deg., respectively.
I think the 446 was available in service for a while, in the '70s. -
Re: 67 BB Vacuum Advance Help
Do yourself a favor and actually check the operation of the reproduction vacuum can against the specs. In my experience many are not even close to the proper spec, regardless of the number on the can.Bill Clupper #618Comment
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Re: 67 BB Vacuum Advance Help
Wayne,
What would be the part number for a direct replacement for the 446 15? I've done some checking and the 446 15 is an obsolete part.Last edited by Dereck S.; April 10, 2010, 11:09 AM.Comment
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Re: 67 BB Vacuum Advance Help
The VAC is worth a total of 3 points - two for originality and one for condition.
I deduct one point if the VAC is replacement "B-number", and the one I recommend for all big blocks is B20 or B26, both of which are 0 @ 6", 16 @ 12".
Recent information is that the B10 is an exact match to the OE 360 (0 @ 6", 12 @ 12"), but it hasn't been verified. The 446 is not the original part number and its specs don't suit big blocks, i.e. it doesn't meet the "Two Inch Rule".
You can do an archive search for B20 and B26 to get a list of brands/part numbers, but I don't think there's any mention of a brand/part number for the B10.
Regardless of what brand you buy, including Delco, it's the same part made by Standard Motor Products.
DukeLast edited by Duke W.; April 10, 2010, 11:19 AM.Comment
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Re: 67 BB Vacuum Advance Help
Dereck-----
The aftermarket replacements for the GM #1973446 are as follows:
Delco #D1377A (same as the original Delco part #, but not the exact same part)
NAPA/Echlin #VC-1807
Standard Motor Parts # VC-183
All of the above are manufactured by Standard Motor Parts and should be stamped "B25".In Appreciation of John HinckleyComment
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Re: 67 BB Vacuum Advance Help
All,
The negative change in run quality was coincident with another issue that arose when I changed the can. After changing the can I got the car out on the highway and stretched it's legs. After that the run quality wasn't where it had been prior to the can change. This lead me to believe the can was to blame. Upon closer examination (taking many hours) I found that the butterfly on the rear carb was slightly hung open on a burr in the bore. After addressing this by a careful deburr the car ran better than ever even with the new can. Clearly the can change was not the issue here. I'm glad to have the correct can 360 12 on the car. Goes to show you have to be patient and more scientific when attempting to isolate issues. Thanks for all the help.Comment
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