1962 Block with 5/16 Oil Filter Adaptor/Valve Bolts

[Michael H.]

Hi. I am looking for some advice. I have an original, early (11/1961) 1962 Corvette 340hp block that I am rebuilding. The block did not have an oil filter adaptor/valve. I was able to source the correct 5573842 with the 1/4 x 1.25 in bolts. Unfortunately, it appears the block is tapped for 5/16 bolts. People say the 1/4 bolts are correct. I did find an old post from Joe Lucia that references 5/16 bolts. What is correct for an early 1962 block? If 1/4 is correct, what do you recommend I do with my block, which is tapped for 5/16?

Thanks,
Mike
40,893

[Patrick B.]

Re: 1962 Block with 5/16 Oil Filter Adaptor/Valve Bolts

Mike—- 350 blocks have 5/16 threads in that location for the spin on oil filter/bypass adapter. I suspect some 327 blocks also had 5/16 threads like yours. In my boxes of junk, I found 2 bypass adapters for old cartridge type oil filters. Both AC parts had the casting number 5573842, but one had holes for 1/4” attaching bolts while the other had holes for 5/16 bolts. It is possible that someone simply drilled out the holes for the 1/4” bolts to accommodate the larger bolts. I would recommend that you drill out the holes of your adapter for the larger bolts or you can have my adapter if you want it.

update: I just checked a 67 427 block and it had 1/4”threads. I guess all the cartridge bypass adapters were made for 1/4” bolts, but there is enough material to enlarge the holes for 5/16” bolts plus clearance.

[Michael H.]

Re: 1962 Block with 5/16 Oil Filter Adaptor/Valve Bolts

Thanks Patrick! I followed your advise.

[Joe L.]

Re: 1962 Block with 5/16 Oil Filter Adaptor/Valve Bolts

Hi. I am looking for some advice. I have an original, early (11/1961) 1962 Corvette 340hp block that I am rebuilding. The block did not have an oil filter adaptor/valve. I was able to source the correct 5573842 with the 1/4 x 1.25 in bolts. Unfortunately, it appears the block is tapped for 5/16 bolts. People say the 1/4 bolts are correct. I did find an old post from Joe Lucia that references 5/16 bolts. What is correct for an early 1962 block? If 1/4 is correct, what do you recommend I do with my block, which is tapped for 5/16?

Thanks,
Mike
40,893

Mike------


1968 and later oil filter adapters did use 5/16-18 X 1-1/8" flanged head bolts for attachment. These bolts were non-trimmed ("indented") head, full thread, and GM 280M material grade .

However, 1956-67 adapters used 1/4-20 X 1-1/4" standard hex head bolts with about 1/4" of unthreaded shank under the head. These bolts were also GM 280M material grade.

I don't know why your 1962 block is tapped for 5/16-18 bolts. Could it be that this is a SERVICE block?

[Barry H.]

Re: 1962 Block with 5/16 Oil Filter Adaptor/Valve Bolts

Mike,
I have 2 early 62 blocks one in my 62, Cast K201, build date, stamped FII2IRF, Nov 21st 1961,
Plus a spare 62 block, Cast K161, build date, stamped FII2IRE, Nov 21st 1961.
Different Casting dates, but assembled & stamped at the Flint Engine Plant on the same day.
Both have 1/4 20 threads for the Oil Filter Adaptor. Hope this will help, but I don't think it would hurt to drill the aluminum adapter to 5/16" & use larger bolts. Would have to remove the Oil Canister & Filter to check! Barry Holmes