what pulleys for 250 -w- air?

[beautimus]

can some one that knows please tell me what pulleys i need for a 250 inline six with power steering and air . or just air?

i really need any help you can give on this one.
i am in the process of gathering up parts for 2 sets of ac brackets and associated parts. if you dont know your part numbers and have access to a running setup could you please post pictures showing the grooves on the water pump pulley, (are the grooves next to each other or is there a space in between etc.) any information you have , or a best guess is helpfull.
thanks in advance, tony

[Jason Banks]

Here is my collections of pulleys, that I have collected in anticipation of adding air conditioning.

The top row of pulleys are ones I have gathered to add a 3rd grove to the harmonic balancer.

3376872 CH - I have seen this listed as being the correct one for 250 with air but it won't work with my truck because it is a bigger diameter than the balancer on my truck.

3790337 E I think this is the one I'm going to use...either that or the next one

3883263 AX This one has an offset to it. Like it would recess into the balancer(much like the 3376762 CH above)

3755820 BC - I'm pretty sure this one could work also.

The bottom row are 3 groove water pump pulleys

3906657 DP has two larger diameter grooves, much like my factory 2 groove. It has a 3rd smaller diameter groove that is smaller than the grooves in the next one...

326304 AI 3 groove all the same diameter




Here's another option:
http://www.vintageair.com/instructions/15249-vcb%20.pdf

They show some completely different ways than factory, but they have part numbers listed.

[RichardJ]

The Vintage Air drawing is very similar to the factory, but the crank pulley will not work.
The alternator is being driven at two different speeds at the same time, because the outside crank pulley is smaller.

Mine is also similar to the factory, but no part numbers, because I scrounged pieces from various wrecking yard engines and modified the 250 PS bracket to fit the 292.
My Sanden compressor and the adjustment part of the bracket came from a VW Cabriolet. I fabricated the mounting to model the Vintage Air piece.

Paint a white line from the pulley timing Mark out onto the outside pulley. If and when the balancer rubber goes bad, the witness mark will no longer line up with the timing mark.

Notice the Vintage Air .pdf says "250 CID 6 cyl Chevy Point Ignition".
The HEI is too tall to fit under their AC bracket. The 292 is taller, which helps and I used the 1975 HEI with external coil.

[PanelDeland]

250 brackets also come in at least two versions(or at least pulley offsets for PS). There may be only one version that lines up with the A/C bracketry, but I haven't gotten that far yet.

[beautimus]

jason banks - thanks man, that's great info there, it looks like you have been
researching this thing for quite a while. maybe we can get enough people to submit enough info to make a sticky on this stuff for future reference.

richard j thanks for the info on the vintage air stuff, i tried the hei with the separate coil on my 250 but it was just too tall. and you sir, have my respect for your ingenuity. , your setup looks like it was put there at the factory.


panel deland thanks for the info on the pulleys. i didn't know that there was more than one type.
keep the info coming folks, pictures are appreciated , anything is helpful and part numbers are good if you got em. i appreciate it

[beautimus]

ttt hoping for more info

[69-72]

I'm doing the same thing, adding ps and AC so I will pass any info I find along.

[Jason Banks]

Over in the parts for sale section....

http://67-72chevytrucks.com/vboard/s...d.php?t=710473

AC Brackets

I would consider getting them, if I didn't have HEI and want to run a Sanden compressor.

[69-72]

Did anyone in this thread get their AC and PS setup going? Just working on figuring mine out now.

[Jason Banks]

Have not done anything yet...

[old51sedan]

Richard,
Noticed you went from a 250 to a 292. I'm doing the same with my 69 C-10. I believe I can make the PS from the 250 fit the 292 also. I have bought Vintage air complete with a compressor mount for the right side, I'm also looking for a short electronic distributor from a newer vehicle, but don't know the years or vehicles to look at. I'm currently in Florida and have excess to a few old yards. I believe that one may fit under the compressor because of the fact that the 292 is taller. I currently have a electronic module in my diet in the 250 that maybe I could use. Also I believe I need a 3 grove crank pulley. Have you been able to find one, or did you use a bolt on for the crank.

[RichardJ]

>>I currently have a electronic module in my diet in <<
What does that mean?

The body/housing of the external coil HEI distributor looks the same as the regular HEI, but the index notch for the cap is in a different location.
I addition to the trucks, the HEI with short cap and external coil was used in '75-'76, X-body Chevy Nova, Buick Apollo, Oldsmobile Omega and Pontiac Ventura with the 250 engine.
A word of caution. I pulled a HEI out of a Olds or Buick and I don't know which, that had a smaller diameter on the lower part of the shaft. When installed in my 292 the distributor wobbled. I thought the shaft was bent and didn't see the step on the shaft until the gear was pulled off. These engines have a brass bushing in the engine block just above the oil pump. You could switch bushings, but easier to switch out another 6 cyl HEI shaft.

>>Noticed you went from a 250 to a 292.<<
Not sure what you mean. My truck was born with a 292. I modified a X-Body 250 PS bracket for use on my 292.

My AC system has been in operation for 12 years. I never bothered looking for a 3-groove pulley. The extra, single groove, outer crank pulley bolts directly to the harmonic balancer inner hub. It has the advantage of trapping the harmonic balancer outer ring in the event it should come loose.

As I mentioned in my post from two years ago, the Vintage Air drawing is wrong. The outside crank pulley diameter is smaller and will not work. The two belt speeds on the Alt would be different.

[old51sedan]

Sorry about the spelling in the last post, diet was supposed to be Dist. The extra single pulley you have added would be great for my application. Do you by any chance know the number on it or what it came off from? Do you have access to another one. I believe I can adapt the PS from the 250 to the 292. I did install the PS when I bought the truck, it had a smog pump on it that I removed, if need be I can rework that bracket. The compressor mount that I received from Vintage Air is a lot longer than yours is, in fact it sits about both number one and two spark plugs. Thanks I appreciate the information, and hopefully it will help someone else also.

[RichardJ]

The Vintage Air bracket uses two bolts at the front and two bolts behind the #2 spark plug. My bracket is the same length. It reaches back with two triangulated pieces of bar stock, to the bottom bolt hole behind #2 plug. Those two bolts also hold the factory support bracket for the air cleaner.

I recommend a trial sparkplug change with that Vintage Air bracket. I intentionally designed as much free space around the plugs as I could and plug changes are still a challenge. I suspect that Vintage bracket could be trimmed considerably.

I don't believe there are any exposed numbers on my crank pulley. I put the AC system together in 2007.
The pulley was installed several years before that, after the previous harmonic balancer came apart and flew off while driving. Nothing was damaged and the pulley was for insurance and a future AC installation. I have no recollection of what the pulley may have been removed from.

Every piece of the AC system is a collection of modified junk yard parts, except the hoses.

[69-72]

Im installing a factory ac a6 brackets with ps on a 250. Im working on a list of pulley part numbers for a 250 going by the gm parts books. It’s quite difficult to decipher everything because the listings are all separated for each pulley and almost each year has a different part number for each pulley. Not all years have a listing for a pulley for AC and PS so I’m attempting to find a common year for all them. I’m just working off of 67-72 books right now My next step is to look at Camaro books. Even the 62 amp alts use different pulleys. 292 uses totally different pulleys as well it seems so I wouldn’t count on what’s working for a 250 will fit a 292.