I'm planning on taking off my intake manifold on my 500 and getting plenum cut out. While I'm doing that I was wondering if there is a way to remove ac compressor but leave pulley on so belt won't change. I've heard removing the extra drag on belt will improve power. Or do I have to remove whole set up and change belt configuration which would be a pain?:confused: Right now I'm just waiting on rebuilt carb so I have a bit of time.

I think that it would be a lot easier just to go ahead and get the right size belt to eliminate the compressor completly. Why are you getting rid of A/C anyways? I doubt you will see much of a difference on the seat dyno.

The compressor hasn't run in 10 years and the lines were all open so I'd just have to start from scratch with whole new system. Not worth it to me at this point. I'll also save about 20 pounds of dead weight. Yeah, you're right about the belt, I'll just get new belt anyways. BTW any idea where I can get cruise control vacuum modulator. The diaphram blew out on the original. I will plug line for now. Thanks

Ah I see. In that case, if you don't need/want it, I would be taking it off anyways. What I would do after it is off is measure around the pullys with a piece of string to give you an approx. belt size, then go to your parts store and ask for one that size.

About the modulator, I think your best bet would be Ebay; see them pop up on there every once in a while for cheap.

Thanks, i just back my rebuilt carb and am having alittle prob with spacer that I'm trying to add to stock intake. I took out compressor, HEAVY I like that string idea so I'll just use old width with new length I guess crank pulley to power steering pully. On same subject, any word on how good the electric water pumps are for these BBs? I'm still trying for cheap HP. Thanks again.

I can honestly say I don't remember any high HP build of a BBCad including an electric water pump, if that tells you something.

thanks for the reply, I never have either but that seems to be something that some of the foreign car guys do. I'll keep on checking

I have seen a converted electric CSR or something for an awesome cooling system on Potters EMC build, but other than that no. IMO it's not worth it because it would have to be custom and wouldn't be ideal on something that isn't an all out race engine, but what do I know?

You don't want an electric water pump on the street. I only know of one or two that even flow enough water for a 350 chevy in street service. Add 472-500ci oc Cadillac motor pumping out heat on a summer day and an electric water pump simply cannot move enough water fast enough to keep it cool.

Reason 2: it will not save you any drag. What powers that electric water pump? The electricity in your car comes from the alternator, which draws power from the engine. You are just switching which accessory is sucking power from the engine. Plus, the alternator is not 100% effecient, nor is your wiring, nor is the electric pump, so you will probably end up with more drag. Yes, the mech water pump isn't 100% efficient either, but that's only one place to lose energy, not three.

Drag racers use an electric water pump for two reasons. First is that they can shut the pump off during the 1/4 mile run. For that short period of time, the engine can deal with having no water flow. With the pump off, you DO have less drag (and many don't have an alternator, so then there is NOTHING drawing power from the engine).
Second reason is that when you get back to the pits, an electric water allows you to shut the engine off to save gas and wear, but still run the water pump (and electric fan) to cool the engine down for the next pass.

I doubt you will feel the difference in removing the AC compressor, but it will save a touch of weight. The clutch on mine spins quite freely, so I do not see it causing very much friction.

A Caddy without AC though... *shakes head* I always thought the point of a hopped up Caddy was to smoke the competition in complete comfort.

re: the cruise modulator, check the junkyards. Caddy used these engines for quite some time and cruise is a very common option. You can test the diaphragm by sucking on the vacuum line to it and see if it moves. Find a u-pull yard and bring your tools, it shouldn't cost very much.
Heck, while you're in there, you might find a working AC compressor, new referigerant lines, etc. I actually know where there is a '69 DeVille whose AC system was intact last time I was there. I'll likely be up in that yard on 5/8 or 5/9, so assuming it hasn't been crushed yet I would be willing to snag it for you. email djohnson1981@yahoo.com if you're interested.

I can always put on a/c later (left original stock manifold on) but for now, I'm concentrating on 2 things- more power and less rust. I use car maybe 4 months top up here so time is crucial. I was going to switch cam (over my head) but I think for now headers and true dual exhaust will improve power with less down time. Already opened up plenum and put in spacer but now was told that actually hurts my low end and won't make up until high rpm which can't do with stock engine anyways (oh well ,live and spend):tisk:

It helps on a stock engine. If it's in decent tune and you try to use all your low end you'll just have a one tire fire anyway, so these motors can afford to lose a bit of low end.