short pump pulley question

[keh27]

I'm changing my 79 engine to be period correct 69 with a short water pump, ps/ ac/ what pulley part numbers do I need? I have all the correct brackets.
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Or sale me a set. thanks

[keh27]

ok can anyone tell me if theses will work 3972180 c17,3927796ag ?

[FirstOwner69]

Which style bracket is your A/C compressor mounted on? I see you read the thread from a couple years ago (http://67-72chevytrucks.com/vboard/s...d.php?t=472147) on this topic so you know why I'm asking. If It's like the one pictured below that is the original on my 69 3/4 ton with 350, I can check my pulley numbers and even post some pictures of the pulleys in a couple days.

[keh27]

Mine is like this thanks......

[FirstOwner69]

That's the more common bracket set. I'll see if I have any pulleys that I can look at to get numbers. It'll be a couple days though. The mounting plate on your compressor looks rectangular. I've never seen that on these trucks. I've only seen square plates. Don't know it that matters other than belt length.

[keh27]

Originally Posted by FirstOwner69

That's the more common bracket set. I'll see if I have any pulleys that I can look at to get numbers. It'll be a couple days though. The mounting plate on your compressor looks rectangular. I've never seen that on these trucks. I've only seen square plates. Don't know it that matters other than belt length.

thanks for you help, I will take a pic of mine at home when I get there, I just found that pic on here, but I know most of its right... thanks

[mr48chev]

You had better check your timing marks on the engine as the 79 engine I had in my 71 had the timing marks straight up at 12 O'clock and with a short pump I couldn't properly time the engine as you couldn't see the marks or get a probe on a scope into it.

That engine was a 350 out of a 79 ElCamino and an engine out of a regular truck may be different but it is something to consider and address while you are doing the swap over.

[keh27]

Originally Posted by mr48chev

You had better check your timing marks on the engine as the 79 engine I had in my 71 had the timing marks straight up at 12 O'clock and with a short pump I couldn't properly time the engine as you couldn't see the marks or get a probe on a scope into it.

That engine was a 350 out of a 79 ElCamino and an engine out of a regular truck may be different but it is something to consider and address while you are doing the swap over.

thanks for the heads up, I bought the correct cover last week

[FirstOwner69]

There's a pic of a small block bracket set in this old thread.

http://67-72chevytrucks.com/vboard/s...d.php?t=520457

[keh27]

this is what all I have

[GASoline71]

Originally Posted by mr48chev

You had better check your timing marks on the engine as the 79 engine I had in my 71 had the timing marks straight up at 12 O'clock and with a short pump I couldn't properly time the engine as you couldn't see the marks or get a probe on a scope into it.

That engine was a 350 out of a 79 ElCamino and an engine out of a regular truck may be different but it is something to consider and address while you are doing the swap over.

Good catch... Had a couple of '79's with 350's myself over the years. one K2500 and a C10. You have to point the timing light behind the long water pump to time it. Not sure how that will work with a short pump, even with the correct timing cover.

Gary

[keh27]

19

Originally Posted by GASoline71

Good catch... Had a couple of '79's with 350's myself over the years. one K2500 and a C10. You have to point the timing light behind the long water pump to time it. Not sure how that will work with a short pump, even with the correct timing cover.

Gary

thanks for the info, and it was a good call, but I have the correct 1969 timing cover

[GASoline71]

True... but the timing mark on the 1979 balancer won't line up correctly to the 1969 timing tab.

Gary

[keh27]

Originally Posted by GASoline71

True... but the timing mark on the 1979 balancer won't line up correctly to the 1969 timing tab.

Gary

yes sir you are correct, thanks

[GASoline71]

10-4!

Gary

[WIDESIDE72]

Fyi the corresponding balancers should be used with swp or lwp. This helps avoid the timIng mark issue. You can run the smaller diameter balancer originally hinted for swap with a lap, but not vice versa. It won't clear.

[FirstOwner69]

Originally Posted by keh27

this is what all I have

It appears you have all the brackets with the possible exception of the brace that runs from the back of the compressor to the "U" shaped bracket that mounts with the intake bolts. I just don't see it in your pictures.

Pulley-wise, the one for the water pump with the 2 grooves looks right. The one on the power steering pump is the one I've seen most and is probably OK. However, I mounted this set on my Vortec head crate engine and had to use the version that's flat (places the groove a groove's width closer to the radiator than the dished pulley). No idea why though. I thought I'd need the one in your picture. I can't make out what the crank pulley setup in your picture is. You need 3 grooves. Usually, this was accomplished by nesting a 1 groove pulley into a 2 groove pulley.

I could not make out the part numbers on my mounted set except for the water pump pulley. It looks like 3939002AH.

Hope this helps. Pulleys can sometimes be more of an art than a science.

Jim