1965 L78 Vac

[Brenton M.]

I purchased a new Vacuum advance can for my 65 L78 engine from Napa the part number is VC1765, It looks a lot different from the one that's on my car now.
Can anyone tell me if there's any modification needed to be made to install this VAC.

[Duke W.]

Re: 1965 L78 Vac

The VC1765 should be stamped B20 or B26 and other than some minor details is dimensionally identical to OE VACs for the single point/TI distributor.

So what's installed now. ID number? Is it a correct TI distributor? A photo would be good, too.

Duke

[Brenton M.]

Re: 1965 L78 Vac

Thanks Duke, I purchased the VAC from a napa parts store using the part number VC1765 the one that they gave me did not look any thing like the one that came on my distributor, So I made a trip to O'reillys Auto Parts I gave them the napa parts number that i had which was VC1765 they cross reference that number to there number V375 was there number, the can looked exactly like the one i took off my distributor it was stamped with the letters B26 i think this is the one i need.

[Duke W.]

Re: 1965 L78 Vac

It sounds like NAPA mispackaged the part, so take it back and let them know.

The B20/B26 is functionally correct for SHP big blocks, and I think L-78 has full time vacuum advance, but check to be sure.

I believe the original L-78 VAC is ...201, but it doesn't meet the Two-Inch-Rule, same as my '63 L-76, which also had the ...201 as OE - didn't meet the Two-Inch-Rule, which caused a lot of idle instability problems.

Duke