Pulley Confirmation

[Keith M.]

So got all the pulleys apart on my 69 350/350 4spd with N40...no a/c. Per the AIM and TIM and JG the correct crank pulley would be GM #3850838. Attached photos are crank pulley that came off Frankenvette. From what I can ascertain this is not a correct pulley as determined by OD which measures 6 3/4" on this pulley and correct is 7 21/64".

1) Am I correct that attached is not the correct pulley?

2) Would a correct pulley have a part number stamped in it? Seems Corv Ctl has the what would appear to be a correct pulley...but cannot ascertain if it is stamped with a p/n...does not appear to be. My goal is to be NCRS correct for judging.

3) How does one discern/measure deep groove vs standard groove?

Thanks!

[Gary B.]

Re: Pulley Confirmation

Sometimes, the numbers are not stamped very deep, hard to see. Wash the pulley real well and see if anything shows up. It might be under the dirt and grease... Post a picture if there is, please.
Also, what head markings were on the bolts.
Gary B

[Keith M.]

Re: Pulley Confirmation

Thanks to Gary's good advice...WTH didn't I think of that. I got the nice photo attached which is where the plot thickens. Obviously from the photo the crank pulley I took off is #3858533 BJ. So I check the JG which states all 327s and 350s use #3850838...mine is a 69 350/350 with N40 and NOT C60. So now I think I got the wrong pulley. Do a web search and see Corv Central has #3850838...but not sure it is stamped, NOS, refurb, reprod so they are checking that for me. Then I see same site has #3858533 as also correct for my car!! WTH? So I know what I'll do...I'll search this site with the part numbers...and came up with THIS thread that seems to indicate 533 is correct....

https://www.forums.ncrs.org/showthre...hlight=3858533

and then this thread indicating 533 is correct....

https://www.forums.ncrs.org/showthre...hlight=3858533

Maybe BOTH are correct? Maybe I am missing something. is the JG incorrect?

BTW...don't have the bolts with me now...but will get them and clean to try to ID headmarks.

PS. AIM says 838!!

[Gary B.]

Re: Pulley Confirmation

As time goes by, "We" learn more. Sometimes, the light bulb comes on and it's a Ah-Ah moment.... The Judging guides are a living and breathing document. As we learn more, we do updates. Today, "we" learned more.

Base engines, 350-300hp has standard groove pulleys. L-46, 350-350hp use a deep groove pulley. The L-46 option is not listed in the AIM. The 3850838 is a standard grrove pulley, base engine. The 3858533 is a deep groove, for the 350hp engines. N-40 equipped engines used a third pulley bolted to the lower crank pulley, it's 3751237 according to the AIM. UPC N40, Sht. A2.

It looks like you have the correct lower pulley. "We" will update the TIM&JG to reflect this.

Still curious about the bolts.

Thanks for your help

Gary Bosselman

[Keith M.]

Re: Pulley Confirmation

As time goes by, "We" learn more. Sometimes, the light bulb comes on and it's a Ah-Ah moment.... The Judging guides are a living and breathing document. As we learn more, we do updates. Today, "we" learned more.

Base engines, 350-300hp has standard groove pulleys. L-46, 350-350hp use a deep groove pulley. The L-46 option is not listed in the AIM. The 3850838 is a standard grrove pulley, base engine. The 3858533 is a deep groove, for the 350hp engines. N-40 equipped engines used a third pulley bolted to the lower crank pulley, it's 3751237 according to the AIM. UPC N40, Sht. A2.

It looks like you have the correct lower pulley. "We" will update the TIM&JG to reflect this.

Still curious about the bolts.

Thanks for your help

Gary Bosselman

Well that is good news. At least Dr. Frankenstein left something original on her. I believe same issue with errata in the JG over water pump pulley for this vette configuration. Attached is photo of mine...which is 3848904 CS. I had already gotten a NOS 419 water pump pulley so that will be going back to Zip.

So now I have 2 pulleys to refinish. Can anyone point me in direction of info on that? JG sez both are semigloss black with crank being dip painted....which I don't know really how to do. Otherwise...thinking I can always clean them up good...maybe use something like naval jelly to remove rust..which as you can see is nasty in the groove areas..smooth out a bit with some emory cloth.....tape off the groove areas and spray with a semi-gloss black that tolerates hi temps? maybe Eastwood has something good? Alternatively does anyone know a place that might just do it all for me including dip painting capability?? Again my goal is NCRS judging. I did already get a NOS water pump pulley

I totally am on board with the "we" thing and hope i can do my part over time to contribute as much as I gain. NCRS and all associated resources is phenomenal. Gold standard for restoration AFAIK. I am not aware of any other organization for other car models that comes close. Wish there was for Camaros. I have waited 20 years to start my restoration in retirement....not retired yet but close enough...and I grin to think about how much more info is available than 20 years ago...but I digress.

Gary, Will definitely get the bolt head info in a followup.

Keith

[Gary B.]

Re: Pulley Confirmation

Thank you for the pulley picture. Appreciate it.
I have been glass bead blasting the pulleys, epoxy prime them and spray paint semi-gloss. Don't worry about paint in the groove, thebelts will wear it off. GM didn't worry about, why should we??
Rust removal with out hurting the paint, try a product called Evap-Rust. Works good.
Again, thanks for your help!!
Gary B

[Keith M.]

Re: Pulley Confirmation

As time goes by, "We" learn more. Sometimes, the light bulb comes on and it's a Ah-Ah moment.... The Judging guides are a living and breathing document. As we learn more, we do updates. Today, "we" learned more.

Base engines, 350-300hp has standard groove pulleys. L-46, 350-350hp use a deep groove pulley. The L-46 option is not listed in the AIM. The 3850838 is a standard grrove pulley, base engine. The 3858533 is a deep groove, for the 350hp engines. N-40 equipped engines used a third pulley bolted to the lower crank pulley, it's 3751237 according to the AIM. UPC N40, Sht. A2.

It looks like you have the correct lower pulley. "We" will update the TIM&JG to reflect this.

Still curious about the bolts.

Thanks for your help

Gary Bosselman

Finally got around to checking out the head markings on the bolts. Virtually impossible to discern. I hit them with some WD40 in the hopes of cleaning enough but didn't do much. Haven't tried a soak yet but I don't know that will help much either. Given the options stated in the JG..I would say it is a WB...but without any preconceived options I would say it kinda looks like a VB...unless the right slant of the W is also the left side of the B. Definitely doesn't look like an A nor an SB...but again ..real hard to tell. They do have the three lines radiating out from the center. Tried to take a pic but doesn't really show much.

Keith

[Joe L.]

Re: Pulley Confirmation

Well that is good news. At least Dr. Frankenstein left something original on her. I believe same issue with errata in the JG over water pump pulley for this vette configuration. Attached is photo of mine...which is 3848904 CS. I had already gotten a NOS 419 water pump pulley so that will be going back to Zip.

So now I have 2 pulleys to refinish. Can anyone point me in direction of info on that? JG sez both are semigloss black with crank being dip painted....which I don't know really how to do. Otherwise...thinking I can always clean them up good...maybe use something like naval jelly to remove rust..which as you can see is nasty in the groove areas..smooth out a bit with some emory cloth.....tape off the groove areas and spray with a semi-gloss black that tolerates hi temps? maybe Eastwood has something good? Alternatively does anyone know a place that might just do it all for me including dip painting capability?? Again my goal is NCRS judging. I did already get a NOS water pump pulley

I totally am on board with the "we" thing and hope i can do my part over time to contribute as much as I gain. NCRS and all associated resources is phenomenal. Gold standard for restoration AFAIK. I am not aware of any other organization for other car models that comes close. Wish there was for Camaros. I have waited 20 years to start my restoration in retirement....not retired yet but close enough...and I grin to think about how much more info is available than 20 years ago...but I digress.

Gary, Will definitely get the bolt head info in a followup.

Keith

Keith-------


This is the correct waterpump pulley for your L-46 application. However, there should also be a 1 groove "add-on" pulley which sandwiches onto the front of the '904'. This add-on pulley drives the AIR pump. Do you have such a pulley?

Your power steering pump pulley should be a GM #3834720. This is a single groove, cast iron pulley.

[Keith M.]

Re: Pulley Confirmation

Keith-------


This is the correct waterpump pulley for your L-46 application. However, there should also be a 1 groove "add-on" pulley which sandwiches onto the front of the '904'. This add-on pulley drives the AIR pump. Do you have such a pulley?

Your power steering pump pulley should be a GM #3834720. This is a single groove, cast iron pulley.

Thanks Joe. The ONLY component of the AIR/SMOG system that Bubba previous owner left on the vehicle were the 8 bolts plugging the holes in the exhaust manifold!! I have already acquired the AIR add-on pulley...and will be working on getting the rest of (entire) smog system...at some point. Haven't got to the power steering pump pulley yet but will check that out.

As an aside....since you mentioned other pulleys...and not to hijack my own thread....just started poking around on the alternator...which though it works, is a complete smorgasbord....appropriate for this Frankenvette. See pix. A knowledgeable source tells me 1) the pulley and fan are not correct for my car, 2) the front casing is a Buick part number with date code 7A26, and 3) the rear case is from a '78 or newer alternator.

Keith

[Joe L.]

Re: Pulley Confirmation

Thanks Joe. The ONLY component of the AIR/SMOG system that Bubba previous owner left on the vehicle were the 8 bolts plugging the holes in the exhaust manifold!! I have already acquired the AIR add-on pulley...and will be working on getting the rest of (entire) smog system...at some point. Haven't got to the power steering pump pulley yet but will check that out.

As an aside....since you mentioned other pulleys...and not to hijack my own thread....just started poking around on the alternator...which though it works, is a complete smorgasbord....appropriate for this Frankenvette. See pix. A knowledgeable source tells me 1) the pulley and fan are not correct for my car, 2) the front casing is a Buick part number with date code 7A26, and 3) the rear case is from a '78 or newer alternator.

Keith

Keith------

The alternator drive end case half is from a 1967 Buick alternator. So, it's a DN series (external regulator) case half that's been used to build up an SI (internal regulator) alternator. Commercial rebuilders sometimes do this.

The alternator pulley is incorrect. It should be a GM #1970831. The latter is a machined steel pulley.