Need help finding the correct diameter of the water pump and crank pulley for a 1970 383 air conditioning challenger. I think one is incorrect on mine.
Thanks

I dont know the OE diameters but post what you have & I'll tell you if there will be an issue with the pump speed (too low-overheating or too high-cavitation). The crank pulley MAY be 7&1/4. Are you wanting it to be OE or worried about incorrect pump speed? Holler back & we'll go from there

well here is the issue:
I just bought this challenger and the engine had issues. SO...

I am rebuilding the 383 with all the right stuff. Roller HYD cam, Harlan sharp rockers, KB pistons, etc. but keeping it looking stock on top. running pump gas. 9.7:1 or so.


It was running hot before I tore it down. It had aluminum billet pulleys put on by the previous owner. I changed out the radiator to a 3 core and it did better but it still ran 195-210++.
So I am trying to get rid of all the dis-tractors that could cause this triple black vert from have any chance of overheating and ruining my good work.

I believe the crank pulley is the 5.25 inch and the water pump is considerably bigger (I don't have the measurements as the pulleys or at the engine shop). I am putting a flowKooler water pump on it also. So that should help.
It was originally an AC car which I will eventually put back on. It was taken off prior to me buying the car.

So, I guess the issue is are these aftermarket performance pulleys worth the 12 hp for a chance on getting hot?

Alright, get me the dia's when you can & does the flow cooler pump have a flat circular "anticav plate" welded on?. When was it running hot, stoplight to stoplight or on the hiway (above ~40 MPH). I'm assuming the mixture/timing is in the ballpark

What are you running for a thermostat?

I've got a 70 383 330 HP challenger at the shop out of the car. I know it's all original. I can give you some measurements tomorrow. I probably have a spare setup if you are interested.

Thanks all.
1. had a 180 thermostat ( I am switching to a 160 after the rebuild)
2. This FlowKooler has the anti cavity on the back welded.
3. Timing and mixture??? timing was 36 degrees all in but only about 6 degrees at idle. mixture at idle I checked twice.
4. Thanks for looking up the diameter.

The real problem is I only got to drive it about 5-7 days since I bought it before the engine decided to bend push rods on #6. Seems the valves were hitting the top of the pistons. ugh. I was still diagnosing things when I decided it was time to pull the engine and go from scratch.

Thanks