69 427 Main bolt

[Verle R.]

While disassembling a 69 390 HP 427 I found a broken mail bolt, one that supports the windage tray.

A GM dealer produced a bolt that they said was the only bolt available for the application. The only problem is, the upper portion, above the main cap, is too short by about 1/2 inch.

I don't think the engine had been apart before, everything was standard with some minimal wear so I think the bolts are original.

I don't have a bolt stretcher handy to get the 1/2 inch for the tray stand.

Does anyone have a suggestion for a source for the original 69 main bolts for windage tray support?

Thank you,

Verle

[Mike M.]

Re: 69 427 Main bolt

Call cresap machine, cumberland, 301 724 8794, ask for JOHN, tell him the crazy one (me) referred you. i was in the other day and was rooting thru mark 4 parts.good luck, mike

[Clem Z.]

Re: 69 427 Main bolt

the threaded part that goes thru the cap and into the block should be 3-3/8" long. the stud you need is part # 3902885

[Joe R.]

Re: 69 427 Main bolt #3902885

Verle,

Got a couple of them in stock still in the GM box. If you need one contact me at 1 501 834-1237. Not selling here but just helping out a fellow NCRS member.

JR

[Joe L.]

Re: 69 427 Main bolt

Verle-----

I don't understand the reason for the problem. As others have mentioned, the original stud used for your application is GM #3902885. That same stud is still available today in the GM parts system under exactly the same part number. The small block stud did change part numbers over the years, but the big block stud has remained available under the same part number. It's hard to imagine that the length specs of the part would have changed while the part number has remained the same, but, I suppose, anything is possible this late in the life of a SERVICE part. Are you sure that the part that you were offered at the GM dealer was, in fact, a GM #3902885 (i.e. was it in a box or otherwise marked 3902885)? This is a 1/2" stud and small blocks use a 7/16" stud so there should be no chance of confusion with a small block. I hope, anyway.

[Verle R.]

Re: 69 427 Main bolt

I don't have the ticket at hand and the bolt was handed across the counter with no box. It is 1/2 inch not 7/16". I'll verify the part number and post this evening.

[Verle R.]

Re: 69 427 Main bolt

Called the dealership with the part number provided and they said they could get the part for pick up Monday. The bolt first received may be a Pontiac or Olds main bolt, still have not established the answer yet.

Thank you all for the help.

Verle