65 326 water pump hub spacing info

[Michael M.]

I know this has been covered but I have searched the archives until I am going blind. I need the front of pulley hub to engine pump mounting surface length if that makes any sense on the 326 water pump . My pump is at a rebuilder and I want to supply him the info so that it right when it returns. 65 327/350. Thanks, Mike

[Philip C.]

Re: 65 326 water pump hub spacing info

Hi Mike if your pump is at a rebuilder and he doesnt know, go get it and send it to someone else, you can have the hub set a little closer to the pump and adjust it your self. note you can adjust it out only, by pulling it against the shaft. Phil 8063

[Peter J.]

Re: 65 326 water pump hub spacing info

Phil,
I got my restored "326" pump from a guy in the business that we all know as the guy you have to buy parts from face to face or you will never get your parts from him. And it was a good looking job but when I mounted the W/P pulley it contacted the face of the pump. I called him and got the, "you must have the wrong pulley argument and after I told him it was the original and worked just fine with the previous, I was told to just put a spacer on the mating surface. Needless to say after threatening this guy for over six months (nine months total time) to get my prepaid pump I was pissed that this re-builder wasn't following a standard rebuild measurement. Anyway I used a GM pulley reinforcement under the pump pulley and alignment has been corrected and clearing everything for several years on this 1966 L-79.

[Wayne M.]

Re: 65 326 water pump hub spacing info

I know this has been covered but I have searched the archives until I am going blind. I need the front of pulley hub to engine pump mounting surface length if that makes any sense on the 326 water pump . My pump is at a rebuilder and I want to supply him the info so that it right when it returns. 65 327/350. Thanks, Mike

Here's the hub spacing for '65 Corvettes (and others). From a Tech Service Bulletin.

[Peter J.]

Re: 65 326 water pump hub spacing info

Thanks a lot Wayne, That is a keeper as I have found a half dozen 326 pumps in the junk yards over the last few years and intend to rebuild a couple as spares for myself. Great source!

[Domenic T.]

Re: 65 326 water pump hub spacing info

I converted my 67 435 BB to factory air and bought all new pulleys and kinda had to do what Phill said.
I didn't put the back plate on till I had the alignment where I wanted it and found the setting on the instructions off quite a bit.

It can be frustrating when you have to trust the shop to do it.

I usually measure them before I take them off and put them back the way they came to me, but on mine I was dealing with all new pulleys and the measurement was about 1/16 off.

All I can say is good luck.

DOM

[Michael M.]

Re: 65 326 water pump hub spacing info

Wayne, Thank you very much! Exactly what I needed. Mike

[John H.]

Re: 65 326 water pump hub spacing info

Here's the hub spacing for '65 Corvettes (and others). From a Tech Service Bulletin.

Wayne -

I've seen other small-block charts that showed 5-9/16" (vs. 5-11/16"); were there differences based on applications or options?

[Joe L.]

Re: 65 326 water pump hub spacing info

Wayne -

I've seen other small-block charts that showed 5-9/16" (vs. 5-11/16"); were there differences based on applications or options?

John-----


It's too bad that Wayne's chart only goes to 1965. I believe that things changed for the 1966 model year. For 1966-70, I believe the Corvette hub spacing was 5-9/16". I'm sure it was so for 1969-70 and I think it was so for 66-68.

[Wayne M.]

Re: 65 326 water pump hub spacing info

John-----

It's too bad that Wayne's chart only goes to 1965. I believe that things changed for the 1966 model year. For 1966-70, I believe the Corvette hub spacing was 5-9/16". I'm sure it was so for 1969-70 and I think it was so for 66-68.

Joe, John and others. --- Yes, I see in 1966 Chevrolet Overhaul Shop Manual, section Water Pump 6K, page 3, there's a table, and under Corvette, for the 327 shows 5_9/16" and for the 427, shows 5_3/4" . They also say same 5_3/4" for the 396's available on other models, so maybe that applied to the '65 L78 as well. {I'm still trying to dig out that '65 TSB to confirm with associated text}

Maybe others with the same shop manuals for '67 could do a check.

[John H.]

Re: 65 326 water pump hub spacing info

Joe, John and others. --- Yes, I see in 1966 Chevrolet Overhaul Shop Manual, section Water Pump 6K, page 3, there's a table, and under Corvette, for the 327 shows 5_9/16" and for the 427, shows 5_3/4" . They also say same 5_3/4" for the 396's available on other models, so maybe that applied to the '65 L78 as well. {I'm still trying to dig out that '65 TSB to confirm with associated text}

Maybe others with the same shop manuals for '67 could do a check.

Wayne -

My '67 Overhaul Manual shows 5-9/16" for Corvettes. Maybe that means Corvettes were 5-11/16" through 1965 and changed to 5-9/16" in 1966? That might be a contributor to the extremely complex 1966 pulley permutations.

[Timothy B.]

Re: 65 326 water pump hub spacing info

Can the change in spacing have anything to do with the water pump hub reinforcement, these are approx. 1/16".

[Peter J.]

Re: 65 326 water pump hub spacing info

Interesting Tim, that is what I used to space my W/P pulley out far enough not to hit the pump body. And it was dead on for alignment with the other pulleys.

[Timothy B.]

Re: 65 326 water pump hub spacing info

Peter,

In the 67 AIM the reinforcement is called out for use.

[Wayne M.]

Re: 65 326 water pump hub spacing info

Peter,

In the 67 AIM the reinforcement is called out for use.

Tim -- in TSB #66-76, of July 26, 1966, they say that effective 1967 SOP, the reinforcement #3720616 will be installed on the Corvette L79; apparently pulley failure was an issue with two or three-grooved pulleys. For service on 1966 L79 Corvettes, the reinforcement was to be added.