1968 427/390 odd water pump bolt

[Russ S.]

I cannot figure out what the lower stud bolt in the water pump in this photo was used to hold. The water pump and fuel filter were replaced over the years but the car was rather original. I cannot find anything in the AIM that would bolt on that location.

Any ideas?stud.jpgshop pic's 096.jpg

[Terry M.]

Re: 1968 427/390 odd water pump bolt

I cannot figure out what the lower stud bolt in the water pump in this photo was used to hold. The water pump and fuel filter were replaced over the years but the car was rather original. I cannot find anything in the AIM that would bolt on that location.

Any ideas?[ATTACH=CONFIG]45569[/ATTACH][ATTACH=CONFIG]45568[/ATTACH]

My belief is there is nothing that goes to that stud in Corvette. I would bet some other model line (perhaps the A-body Chevelle, Cutlass, Lemans, etc.) used it. There is a similar and more obvious stud on the small block thermostat housing that has similar application. This is just my SWAG though.

[Edward J.]

Re: 1968 427/390 odd water pump bolt

Russ, my guess is that the water pump was replaced and that the stud goes in the upper hole of the W/pump behind the A.I.R. bracket then the a nut and Washer retainers the bracket. I don't have a AIM for 69 but it may show it for your engine code.

[Russ S.]

Re: 1968 427/390 odd water pump bolt

I thought about that also but the bracket does not fit over the stud correctly. It fits perfect when the bolt passes through the bracket w/o anything between the bracket and the pump. The bolt for that location is longer also to pass through the bracket.

[John C.]

Re: 1968 427/390 odd water pump bolt

Russ

The stud is in the wrong hole on the water pump. It should be on the other side and is used to hold the A.I.R. tension arm as shown in the attached picture.

John

[Keith B.]

Re: 1968 427/390 odd water pump bolt

My belief is there is nothing that goes to that stud in Corvette. I would bet some other model line (perhaps the A-body Chevelle, Cutlass, Lemans, etc.) used it. There is a similar and more obvious stud on the small block thermostat housing that has similar application. This is just my SWAG though.

Yes Chevelles use that stud for the nagitive battery cable

[Russ S.]

Re: 1968 427/390 odd water pump bolt

Perfect. My A.I.R. tension arm was bolted straight to the pump. This makes sense and did not occur to me. There is so much good knowledge on this board.

[Terry M.]

Re: 1968 427/390 odd water pump bolt

Well I sue blew that one. I never did like those big blocks in Corvettes.

[Terry M.]

Re: 1968 427/390 odd water pump bolt

And it makes you "think" even if the subject isn't directly applicable to your situation or cars.

I'll now be thinking about A and B-car big block battery cable routing for the rest of the day. I remember that stud, and vaguely the routing. I know the accessory mounts changed for 69, and the negative cable is attached to the top of the alternator bracket with a big star washer.

This is for Terry: I didn't think the 427 was ever officially offered in A-car, and the other carlines you mention like Cutlass, etc did not use Chevrolet engines until mid 70's when the "corporate engine" thing began. The 427 even in full-size was very, very rare in other than police cars. The prevalent big block in A and B-car was of course the 396. Which may well have used the same water pump attaching hardware as the 427/390. maybe that's what you meant? Cheers.

Dave. You are right about the Cutlass, GTO and GS (BOP A-bodies) regarding Chevrolet engines. I should have thought harder and longer about that before I posted. However anyone could get a 427 in Chevelle in 1970 and newer. There were some COPO 427s earlier (and I am sure that is at the root of your "official" disclaimer), but 427 cid in 1970 and newer A-bodies and especially the 1970 LS6 sets the Chevelle guys on fire. You are quite right that the 396 was much more common than 427 in A & B cars, but there are some very collectable versions of both engines in both those body lines

The point I was trying to make, and I did it poorly, and maybe not at all, is that if one is the process engineer directing assembly of many hundreds or even thousands of engines a day, the finer details of whether some location gets a stud or a bolt is going to be reduced to the simplest terms for the assemblers. Also considering if you are ordering a hundred thousand of a bolt or the same number of a stud the incremental cost differential for each unit becomes minimal. The process engineer also has to consider whether a different tool will be needed on the line to install the different fastener. Then there is the difficulty of the assembler identifying and installing the correct fastener for the application. When all these considerations are weighed it is sometimes more expeditious to use the stud for all applications, and swallow whatever incremental cost differential there might be in favor of being sure the proper fastener is in place for all uses of the engine.

In any case I was clearly off base in this case because the stud has a useful position on the other side of the water pump.

[Joe L.]

Re: 1968 427/390 odd water pump bolt

Dave. You are right about the Cutlass, GTO and GS (BOP A-bodies) regarding Chevrolet engines. I should have thought harder and longer about that before I posted. However anyone could get a 427 in Chevelle in 1970 and newer. There were some COPO 427s earlier (and I am sure that is at the root of your "official" disclaimer), but 427 cid in 1970 and newer A-bodies and especially the 1970 LS6 sets the Chevelle guys on fire. You are quite right that the 396 was much more common than 427 in A & B cars, but there are some very collectable versions of both engines in both those body lines

The point I was trying to make, and I did it poorly, and maybe not at all, is that if one is the process engineer directing assembly of many hundreds or even thousands of engines a day, the finer details of whether some location gets a stud or a bolt is going to be reduced to the simplest terms for the assemblers. Also considering if you are ordering a hundred thousand of a bolt or the same number of a stud the incremental cost differential for each unit becomes minimal. The process engineer also has to consider whether a different tool will be needed on the line to install the different fastener. Then there is the difficulty of the assembler identifying and installing the correct fastener for the application. When all these considerations are weighed it is sometimes more expeditious to use the stud for all applications, and swallow whatever incremental cost differential there might be in favor of being sure the proper fastener is in place for all uses of the engine.

In any case I was clearly off base in this case because the stud has a useful position on the other side of the water pump.

Terry------


One couldn't get a 427 in a Chevelle in 1970. However, you could get a 454. After 1969, the 427 big block was discontinued in passenger cars and replaced by the 454. The 427 did continue in trucks for some time, though.

[Dale C.]

Re: 1968 427/390 odd water pump bolt

John
Back onto the smog brace attachment. Mine has a bolt and not that nut-stud type attachment. The AIM showes a bolt L36, A7 #1 (180122). Anyone know what this 180122 would be?
Dale

My Smog Brace.jpg

[Dale C.]

Re: 1968 427/390 odd water pump bolt

John
Talking about braces, did you know there is a different brace (shorter slot) for the 68 smog pump brace? John Greenhoe told me about that and the AIM does show a 3921903 for 68 and a 3955221 for 69.
Dale

[Terry M.]

Re: 1968 427/390 odd water pump bolt

Terry------


One couldn't get a 427 in a Chevelle in 1970. However, you could get a 454. After 1969, the 427 big block was discontinued in passenger cars and replaced by the 454. The 427 did continue in trucks for some time, though.

OK, Joe & Dave are right -- and to solve my problem I am giving up this thread and stick to something I know about. Now what was that?

[John C.]

Re: 1968 427/390 odd water pump bolt

Dale

The stud is the correct configuration. The stud would be part of the engine assembly and should not be called out in the AIM. I'm traveling this week so I don't have access to an AIM to confirm 100% what it shows, but if I'm not having a Terry moment it is shown with the stud.

A vaguely recall a previous post that may have discussed the different slot length in the 68 to 69 smog pump brace, but no I would not have remembered if someone had asked me. When I get home tomorrow I'll have to compare what I have on my 68 vs. my 69.

John

[John C.]

Re: 1968 427/390 odd water pump bolt

Dale

You are looking on the wrong page in the AIM for the A.I.R. attachment. The 180122 bolt is being used to hold the alternator brace. Look at page L36, A3 in the AIM. You can see the nut and lock washer that are used to attached the A.I.R. brace to the stud.

I took a quick look at my 68 vs. 69 A.I.R. braces and they do appear to have slightly different length slots. Some day I'll get around to removing them to measure and photograph the difference.

John