Strange question here. Are all single groove basic water pump pulleys (balancer, water pump, alternator) supposed to be the same size, depth-wise? I have three different engines, a 73, 79, and 83 slant.
The 73 is bone stock from a 73 Duster, I pulled it myself. Basic single barrel slant, no power accessories.
The 79 engine is from a 79 Volare I had, original engine, (had power steering and A/C) now built up for my 65 Belvedere, no accessories. I have a new FlowKooler water pump on this engine.
The 83 engine is from a Dodge D100. This one had power steering and A/C. The water pump and alternator ran off the single groove crank damper (single groove). This is also an unmolested engine.
With just these three engines to compare, I am seeing three different pulley depths for the same alternator/water pump/crank single belt setup. Has anyone noticed anything like this? I thought they would all essentially be the same, but these engines vary anywhere from 1/8 inch to 3/16 (just under 1/4) inch. The difference is small enough for shims to correct, but I was just curious if I just happened to get three odd balls.

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-MattMan
LEANED & MEAN

Yes, you will find that the pulley up t0 1976 for forged crank units are the same... The 1976-1987 cast crank dampers moved the belt groove to
a different location on the damper ring slightly, and I noticed that using the later pulley on my rebuilt forged crank engines needed a bit of fudging
on the damper install depth or a shim on the pulley... I also noticed that some aftermarket water pumps had a slight variation in depth due to quality
control of the host country...

I never mocked up one of the unitary 3 belt groove HD dampers to see the variation.

Most of the time a daily driver build, one may not notice that 1/8" of misalignment...but you do notice when you toss the belt on a 6000 rpm launch.

Yes I have seen it too.

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2 Mopars come with Spark plug tubes. One is a world class, racing machine. The other is a 426 CI. boat anchor!

12.70 @ 104.6

I have just installed a 3 groove damper. It does not line up with the original water pump pulley on the 77 D200 engine I have it installed on.

Working towards a 2 groove water pump pulley taken from a 74 D600 w/ a 318, and adding 1" spacer between the water pump flange and the pulley.

I put one of those on my '62 Lancer (aluminum 225/forged crank). No power steering in that car, but it did have Mopar A/C. The water pump/fan/alternator (middle) and A/C (rearmost) belts lined up just fine with the middle and rearmost sheaves in the damper.

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一期一会
Too many people who were born on third base actually believe they've hit a triple.

I was wondering about that. I just got a 3 groove damper yesterday, it's marked '77 on the box and is thought to be NOS.
I thought that back in the day those were used on mostly industrial engines. That was what I had read somewhere (maybe the damper rebuild company site? Don't remember now where I'd seen that bit of info.
My question on usability is that 77 should be a cast crank. Did they change the rules on that for industrial engines?
I'm thinking about using it on my '74 eng with forged crank, cuz I eventually want to add AC to the truck it is going into.
When it comes to swapping dampers around, with all the talk about how much lighter a cast crank is, will it hurt anything to use a damper meant for a cast crank on a forged crank or vise versa?

The 3-groove damper was a heavy-duty truck item, not an industrial-motor item. Last time I went digging down this particular wabbit hole was some years back, but I think I recall finding this 3-groove damper, with just the one part number, listed in '74 through '77 parts cattledogs. That spans the forged/cast crank changeover (which happened on all Slant-6s, including trucks). I never experienced any trouble or saw any problem resulting from using these on forged-crank motors.

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一期一会
Too many people who were born on third base actually believe they've hit a triple.