Original 55-57 "TR" fuel pump bolts

[David L.]

Can someone confirm that the bolts in the photo below are original 55-57 Corvette fuel pump bolts. The 9/16" hex head bolts are 3/8"-16 with an effective length of 1.0" and a threaded length that measures about 0.65". The head marking is "TR" with 3 radial line segments spaced at 120 degrees. I removed the bolts from a 56 or 57 Chevy engine that was just sitting on the ground in a junkyard in Lancaster, MA, back in May 1991. The fuel pump was stamped "4262".

Dave

[Adam S.]

Re: Original 55-57 "TR" fuel pump bolts

For 1957 should be grade #2 at 1&1/2 long. I have the WBC2's on mine, plane & TR is correct as well. That bolt in your picture is grade #5 & 1 inch long .I would venture to state your bolts would be incorrect for 1956 & 57. I do not know if this was a normal occurance with GM that they would use a better grade bolt than engeneering would call out for? This may be too short for the correct bolt as well, sure someone will chime in to help out.........

[Ed H.]

Re: Original 55-57 "TR" fuel pump bolts

David,

A review of the current 56-57 Tech Guide, 5th addition, page 106, the bolt is part number 179840, TR, WBiC or Plain, grade 2, Hex head, 3/8" X 1.5, with lock washer. If you need the bolt, Dick Fortier, listed in the DriveLine will have them. ;

[David L.]

Re: Original 55-57 "TR" fuel pump bolts

Ed,

The 3/8"-16 X 1.5" bolt seems a bit too long for fuel pump bolts. I have a pair of NOS 3751842 fuel pump bolts used on later models (1962 Corvette AIM) that are listed as 3/8"-16 X 1 1/8" in my 1964 Chev. Parts Catalog (Oct. 1963). I have other fuel pump bolts from Chevrolets and Corvettes made in the 1960's that are similar in length. The 3751842 bolts have a 7/16" hex head with a captive lockwasher. It would seem to be that the 1955-1957 fuel pump bolts would be about the same length. I really think that my "TR" 3/8"-16 X 1" fuel pump bolts are original as the "4262" fuel pump was only used in 1955 and early 1956.
I really do not have a lot of faith in the NCRS judging manuals or technical guides.

Dave