Modern A/C swap from donor?

[Supa.Slo.SS]

Has anyone ever swapped out there old R12 A/C system for a "modern" system with R134 from a donor car? I have the original 305 & at first glance it seems the biggest obstacle is having the right bracket to mount the compressor & maybe different/custom fittings for the accumulator. I have a GM donor truck with an LM7 that I will be swapping in within a year, so I have the entire AC system. Is there a company that makes the brackets to mount a modern compressor? Is it more complicated than I think? Would the drag on the motor be more or less when running the A/C? FYI, I am aware of the Vintage Air & other retro system but they are a little to pricey for me. Also, because I will be doing the LS swap, I think it's a waste to buy already expensive R12 Freon to eventually pull that system out.

 

[81cutlass]

Depending on the block/frame mounts used you can use a pump from a v8 GMT360 (envoy, Rainier) , the stock GMT800 pickup bracket is fine and the same, but the pump itself is different and the outlets are in the way of the frame.

You just need to find adapters and new hose. The evaporator and condensor can be reused if they are clean. Replace the drier.

 

[Supa.Slo.SS]

Thanks for the info I will keep this in mind when I swap the engine but I believe you misunderstood my question, what I am trying to do is adapt the A/C system from the GMT800 donor onto my first Gen Small Block Chevy .

 

[Longroof79]

If you plan on doing an LS swap in the near future, why concentrate on retrofitting an A.C system for your current smalblock? It sounds counterproductive to me. Why not just gather up the necessary A/C parts to install with the LS engine?

 

[Supa.Slo.SS]

Longroof79, because 1) getting the LS in, in a timely manner is wishful thinking as it usually takes 2x to do what I want to do, so 2 years without AC is why I am looking to see if this is an option, 2) I have the donor, so if someone already makes the bracket then everything should be pretty straight forward. But maybe I should just rip the band aid and do the swap.

 

[81cutlass]

Now that I understand,

No. Nobody makes brackets to mount LS compressors to SBC's that I am aware of. The LS compressors are FAR much less universal than previous styles. The R4 compressor and Sanden styles have universal/standard brackets so a R4 compressor from an olds would fit on a Buick V6 and on a SBC. But, LS stuff is kinda application specific and a F body AC compressor is different than a V8 Trailblazer and it's different than a Tahoe which is again different than a V6 4.3 sierra.

There is really no benefit to running a LS style compressor on a SBC. You can make an R12 comp run on R134 so no issues.

If you want to use a compressor that is forward/backwards compatible you can do one of two things.

1. Get your stock SBC R4 style compressor converted to R134a working and when you do LS swap buy a Holley, dirty Dingo or any of the many R4 to LS compressor bracket kits

Holley 20-140 LS High-Mount A/C Accessory Drive Kit - Includes R4 A/C Compressor, Tensioner, & Pulleys

Now available from Holley are complete A/C kits that have everything needed for the application. Already have the P/S pump and alternator system from the donor truck or car engine? These complete A/C brackets kits move the compressor up high and away from the frame rail (no more notching!)...

www.holley.com

2. Buy a Sanden compressor adapter kit for the SBC and then buy another adapter bracket kit for the LS.

Small Block Long Pump

Small Block Chevy Long Water Pump Accessory Steel Mounting Brackets

www.alangrovecomponents.com

LS

348 - 409 Chevy Mounting Brackets

www.alangrovecomponents.com

I have no preference for Holley, Dingo, or Alan Grove stuff, never used any of their products, and there are a ton of other options available.

Personally I like the Sanden compressor option if you don't have an existing set of AC hoses or an existing R4 compressor.

 

[Longroof79]

Longroof79, because 1) getting the LS in, in a timely manner is wishful thinking as it usually takes 2x to do what I want to do, so 2 years without AC is why I am looking to see if this is an option, 2) I have the donor, so if someone already makes the bracket then everything should be pretty straight forward. But maybe I should just rip the band aid and do the swap.

Hey, I understand where you're coming from. It's hard enough to pinpoint when you're actually able to do the LS swap, so why not have a working A/C system in the car in the meantime while you're gathering parts and putting money aside to buy the necessary mounts, fuel system upgrade, electronics, etc.
If you already have the basic R4 compressor/ system in the car now, I'm sure you'll be able to have it gone over and make it functional without breaking the bank.

 

[Streetbu]

Also look into a new condenser. Your old one will physically work, but isn't sized properly for R134A.

But why do you want to switch? Have you ever felt a properly running R12 system? I've literally seen frost coming out vents before with a good system. 🤣

 

[airboatgreg]

Do you have factory air now?

 

[08Malibu]

Also look into a new condenser. Your old one will physically work, but isn't sized properly for R134A.

But why do you want to switch? Have you ever felt a properly running R12 system? I've literally seen frost coming out vents before with a good system. 🤣

This is good to hear. I was bummed that I mistakenly threw my original condenser in the trash thinking it was the old one from my wife’s car. Now I know I would have had to repair anyway.