need part # application

[Wally A.]

i have a 2 groove pulley on my 63 C-2 not sure if it is correct. 327-340 hp. gm part #GM 3766987 is this correct. it is a 2 pc. design... thanks wally

[William C.]

Re: need part # application

According to'65 Parts book, I come up with 3770245 stamped on the pulley, one piece two groove 7 1/8 OD. '63 Assembly manual confirms same part. I can't find a reference in the '65 book for your part.

[Wayne M.]

Valid Gr 1.062 w.pump pulley #

at least 'til 8-64, at which time it was replaced in SERVICE by # 3858533, but I can't find that one either in my July '65-up Chevrolet parts catalogs.

[Joe L.]

Re: need part # application

wally----

GM #3766987 is the correct harmonic balancer pulley for a 1963 340 hp Corvette application. This pulley is a 2 groove pulley of 6-3/4" OD.

[Jim L.]

Re: need part # application

that is the correct number except there is two different design configerations.
original pully installed on 63'- 340 & 360 show no belt grooves on the inner part of pully and a flat metal ring with dashes on it, there is a seam that is brazed together when the pully groves are formed but service replacements pt #3858533 does not have these configerations but does function the same. the originals were also used on 348/409 engines w/ps--- still hard to find. it took me 5 years to finaly obtain one. i have both styles if a picture would be helpful.

jim

[Wally A.]

Re: need part # application

thanks for all of the response i received.. learn something new everyday....

[Tracy C.]

Re: need part # application

Hi Jim!

Good to see you here on the discussion board! I'm sure you will bring alot of excellent knowledge to us here.

Here is a pic I took of the early style pulley on your chassis back at the regional meet in Breckenridge last year. This one was the first and only example I have ever seen with the flat metal ring with dashes on the internal surface of the pulley.

I appreciate you letting me shoot 2 or 3 rolls of film on your chassis that day. I've refered to these pics many times.

tc

[Jim L.]

Re: need part # application

Tracy,
you are so very kind.thanks for the feed back,just trying to make the hobby more interesting for all!!! i must tell you, one difference on that picture. the bolts securing pully & crank were not the original ones, because i could not find them at the time, BUT i now have-em & they were right where i put-em. they are WB's for the pully and a grade 8 w/o hole in it for the crankshaft, all are black bolts and L/washers. give me a "e" if i can be of any help in finding the pully.

Jim

[Joe L.]

Re: need part # application

Jim------

Yes, the balancer center bolt for all small blocks using a center bolt was GM #3815933. Earlier versions of this bolt have no safety wire hole. Later versions do have the hole. Apparently, at some point the specifications for the bolt were revised. I don't know why or when, though. The 3815933 bolt remains available to this very day (with the safety wire hole).

The strange thing, though, is that GM never used safety wire on this bolt as far as I know. I don't know of any other application where GM used safety wire, either. It's just not the kind of thing used in mass production of autombiles. Other, more "production-friendly" fastner locking systems are used.

[Jim L.]

Re: need part # application

Joe,
With reguards to which bolt to use, i say -----
my object to restoring is Not to make it like the book, cause it is not the final answer. so i choose to put the parts back together the way i found them, unless there is definitive proof otherwise. Research-research & more research is all it takes, not "i think maybe". that's why this forum is the place to learn from. thanks for your knowledge to this hobby Joe.

Jim

[Joe L.]

Re: need part # application

Jim------

No doubt about it; "putting it back the way you found it" is the way to go. This assumes, of course, that you are pretty sure that the way you found it is how it originally was. That's hard to determine in some cases. Also, many folks do not have the luxury of putting it back the way they found it. Usually, this is because the way they found it is quite obviously non-original or because they started from a point where nothing was there to be found.

[Jim L.]

Re: need part # application

Right on Joe!!
you're the kind of people i'am use to working with. i have the luxury of 4 cars within 100 numbers of mine that are very original but not new condiction to use as a comparison. my picture library is quite extensive and as you know, what people say about a "picture being worth a thousand words". in fact that is what i did today, to look at a 95 thousand dollar '63 SWC and take pictures for the library. and i filled in one of the missing pieces to my puzzle with reguard to the hole size of the cork gasket on the high HP motor oil filler cap. now i know the answer!!!!this was the real deal gasket---

Jim