1970 LS-5 Alternator Pulley, revisited

[Kenn S.]

Part of the fun of restoring one of these is learning the details (no matter your definition of restoration, ie: previous thread). At least I find it so.

To that end, my 1970 LS-5 with C60 but no N40 is missing it's '884 alternator (has aftermarket service replacement). I found one with a perfect date code (0A30 for my T0211 engine), but it has a machined pulley, P/N 3829387. The number is clearly stamped on the pulley (nice part, good patina leading me to believe it's not a fake).

My 1983 parts book claims that's for a monster '69 427 (thinking L88). The same parts book confuses the heck out of me for what my part should be. I'm learning to distrust that book (but the exploded assembly pics are good, better than most Xerox'd pics in the AIM).

Given the confusing nature of alternator pulleys in general, perhaps this is a good find? Would a judge axe the pulley because it's machined versus stamped? If it's a real part for an L88, it's an incredible find but incorrect for my car.

Thanks for any insight. I know from searching the archives that it's not an easy detail to track.

[Warren F.]

Re: 1970 LS-5 Alternator Pulley, revisited

Kenn,
That number 3829387 is not listed in my '71 year Corvette parts book, apparently already superceded to another by then. I think the application for your car is 3846180 which is 3 3/64 O.D. and 43/64 Shaft Dia. and 1/2 Groove Width and stamped steel construction. At least this is my best guess of your car's application with its configured options.

[Ronald L.]

Re: 1970 LS-5 Alternator Pulley, revisited

Might be worth a call to John Pirkle to get the details on what is correct.

[Kenn S.]

Re: 1970 LS-5 Alternator Pulley, revisited

'Fraid I don't know John... Would you have a number, and does he mind calls out of the blue?

[Kenn S.]

Re: 1970 LS-5 Alternator Pulley, revisited

Thanks, Warren. I wondered about a machined part. It is listed in the 1983 "Parts and Illustrated Catalog," 2.274, page 2-11 (69 Y (427) W/H.D.), but I'm learning that you can't depend on that catalog. Parts were way superseded by 1983.

[Ronald L.]

Re: 1970 LS-5 Alternator Pulley, revisited

Look him up on the member list or in the Driveline - this is his business, so the answer has to be yes.

[David L.]

Re: 1970 LS-5 Alternator Pulley, revisited

Kenn,

A 1983 parts catalog is generally useless when trying to find original part numbers for 1970 models. I have over 55 vintage Chevrolet parts catalogs but nothing specifically for the 1970 Corvette. I have several 1970 Chevrolet parts catalogs (Sept. 69, Nov. 69, Jan. 70, and Oct. 70) but none of them cover the Corvette.

My 1969 Chev. parts catalog (Oct. 68) lists the following alt. pulley part number in Gr. 2.274:
66-69 Corvette (C.A.C. w/H/Per.)(427)(exc. P/S).......3846180

My 1969 Corvette parts catalog (Oct. 1969) does not list any alternator pulleys, just alternator fans.

My 1972 Corvette parts catalog (Sept. 71) lists the following:
70-72 Corvette (454)(exc. Sp. H/Per., P/S)........3846180
71 Corvette w/Sp. H/Per. (454)(exc. P/S)......... 3829387

pulley # 3846180 has a 3 3/64" O.D.
pulley # 3829387 has a 3 5/8" O.D.

My guess is that the 3846180 pulley is probably correct for your 70 Corvette (454)(w/C.A.C.)(exc. P/S).

Does your car use a 3889371 W/P pulley, a 3921923 C/S pulley, and a 3940991 fan belt (15/32" - 53 1/2") that runs in the 2nd track?

My 72 Corvette parts catalog lists fan belt # 3940991 for the 1970 Corvette (454)(exc. P/S). GM # 3940991 was replaced with GM # 3845654 (also 53 1/2") in April 1973.

I would say that most judges would have absolutely no clue what pulley is correct for your car.

Dave

[Kenn S.]

Re: 1970 LS-5 Alternator Pulley, revisited

Does your car use a 3889371 W/P pulley, a 3921923 C/S pulley, and a 3940991 fan belt (15/32" - 53 1/2") that runs in the 2nd track?

To be honest, I've not taken the W/P pulley off. I'm building a garage where I can finally begin the restoration process. I've resisted doing much disassembly because I know parts will wind up all over, and I'm sure momma won't thank me for that. Meanwhile, I'm trying to find NOS/vintage parts I know I'll need and stockpiling.

As for belts, I'm fairly sure the belts on the car aren't right. It's missing the W/P entirely. (Hasn't run in over 20 years...kind of a barn find thing.)

I figured it was a confusing subject, based on archived discussions. Thanks everyone for chiming in.

[G A.]

Re: 1970 LS-5 Alternator Pulley, revisited

3829387 was also used for '69 L-71 and L-89. As far as I know, the part number goes back to 1966. Sounds like you may have discovered a rare alternator for a hi-perf 71??

[David L.]

Re: 1970 LS-5 Alternator Pulley, revisited

3829387 was also used for '69 L-71 and L-89. As far as I know, the part number goes back to 1966. Sounds like you may have discovered a rare alternator for a hi-perf 71??

I believe that the 1100884 61 Amp alternator was only used in the 1969 & 1970 model years.

[Terry M.]

Re: 1970 LS-5 Alternator Pulley, revisited

I believe that the 1100884 61 Amp alternator was only used in the 1969 & 1970 model years.

Quite true David. And I would agree with your comment in the earlier post (about judges knowing which pulley is correct by part number) although given Kenn's configuration I think most judges would not like the machined pulley -- at least I wouldn't, but then he is unlikely to get me as a judge or his car.

Kenn -- There was recently a thread about the split ring end differences between 1969 and 1970 -- and those features are well covered in the recent and distant past on here. That is one of the most talked about alternators in the world. Congratulations on finding one -- if it is real.

[Kenn S.]

Re: 1970 LS-5 Alternator Pulley, revisited

...split ring end differences between 1969 and 1970

Interesting...not a term I'd heard before. I'll search the archives.

For me personally, I think I'll use it as-is for the moment. Car needs restoration anyway, so no rush. There are enough dated parts I need to find that it won't achieve Top Flight for some time, and we all know what finding those kinds of parts is like. Need a 7040205 carb...ouch.

But I'll keep looking for the right pulley while I'm at it. It sounds like this one isn't right, which is too bad...it's a very nice pulley.

Most talked about alternator, eh? No wonder they're so hard to find.

[D S.]

Re: 1970 LS-5 Alternator Pulley, revisited

Interesting...not a term I'd heard before. I'll search the archives.

For me personally, I think I'll use it as-is for the moment. Car needs restoration anyway, so no rush. There are enough dated parts I need to find that it won't achieve Top Flight for some time, and we all know what finding those kinds of parts is like. Need a 7040205 carb...ouch.

But I'll keep looking for the right pulley while I'm at it. It sounds like this one isn't right, which is too bad...it's a very nice pulley.

Most talked about alternator, eh? No wonder they're so hard to find.

7040205

http://cgi.ebay.com/ebaymotors/70-1970-Chevelle-SS-Carburetor-LS5-454-Engine-7040205-/200638628685?pt=Motors_Car_Truck_Parts_Accessories&hash=item2eb6fe834d

[Jim T.]

Re: 1970 LS-5 Alternator Pulley, revisited

Interesting...not a term I'd heard before. I'll search the archives.

For me personally, I think I'll use it as-is for the moment. Car needs restoration anyway, so no rush. There are enough dated parts I need to find that it won't achieve Top Flight for some time, and we all know what finding those kinds of parts is like. Need a 7040205 carb...ouch.

But I'll keep looking for the right pulley while I'm at it. It sounds like this one isn't right, which is too bad...it's a very nice pulley.

Most talked about alternator, eh? No wonder they're so hard to find.

Kenn I still own my bought new 1970. My 350/300 with air conditioning came with the 884 61A alternator. It failed after about 4 months and was replaced under the new car warranty. If I had known in 1970 how scarce the 884 would become I would of just had it repaired.
The replaced alternator was not a 884. The service writer told me they put a higher output replacement on, a 62A. Alternator numbers did not mean anything to me and NCRS was still a few years away for the C1/C2 Corvettes.

[David L.]

Re: 1970 LS-5 Alternator Pulley, revisited

Kenn,

I do not have a 7040205 carb but if you need a temporary carb until you find the correctly dated 7040205 carb I have a 7040208 carb for very cheap money.

Dave