Factory crank pulleys of different size/weights?

[CRXsi]

Hey gang, hoping to find some gurus that have experience with different years of 88-91 D16A6 motors. I have several used engines sitting in my garage and am in the process of putting my car back together. I just had the motor out for some minor body work and decided to replace the head gskt while it was out as precaution. When I went to put the crank pulley back on I happened to glance at 2 of the 4 motors I have sitting in the garage. 2 had crank pulleys that looked the same as what was on my car (bigger mass to them) and 2 had pulleys that look like they have significantly less mass to them. I removed one of the lighter looking pulleys and carefully inspected it. It is not aftermarket and is definitely OEM Honda but has definitely less weight and not as much mass to it. I can get pictures later if needed. I know that 88 snouts are slightly different so I tried fitting to the crank on my 89 and it fits fine. Both the engines are 89 or newer (not sure exactly what they came out of, one was a CRX as it had a 4.25:1 final drive trans, the other came with no trans.) All pulleys appear to have the same diameter but definitely less mass? Was there a difference between Civic and CRX engines? Difference between years?

Anyone run into this and are there any opinions as to which one would be better to run. Assuming they are factory pulleys (which I am 99.9% sure of) then one would assume the one with less mass is the better. I do also recall the recent thread about light weight pulleys and possible bearing damage but that was with drastically less weight. These pulleys have less weight but not as much as a lightened aluminum pulley.

If pictures are needed let me know and I'll take some.

[tom91ita]

my 1988 crx si had the much smaller underpulley (mass wise) and the 1990 civic si and junkyard motor from either a 90 or 91 crx si had the heavier underpulley with the hard rubber dampner insert in the back side.

my 1990 crx hf has an underpulley that looks remarkably like the 88 si pulley.

the 88 crx si, 90 civic si and 90 hf were all bought used but i am also convinced they were stock pulleys.

[Domino]

Check the part numbers.

http://www.hondapartsdeals.com/honda_parts.php

[tom91ita]

1990 crx HF 13810-PM8-A01 ($69.85)

1990 crx si 13810-PM6-003 ($119.77)

1988 crx si 13810-PM6-003 ($119.77) and 38921-PM3-Y00m ($69.85)

which may or may not mean anything. some parts that are superseded will show the new part numbers.

at least the price implies the same level of complexity between the two underpulleys.

[R2 Racing]

Uh oh, look out! Tom Blaney's going to come and yell at you now for looking up part numbers!

[CRXsi]

Part numbers aren't answering whether or not I can safely run the less mass pulley safely on the motor that currently has the bigger mass pulley. Just cause they are a different part number doesn't mean that it was designed for that motor. I am wanting to know if anyone has experience with swapping to the light mass pulley and what the results were both in power and in longevity. And yes all the motors I have are si motors...just don't know ehat years they are from and whether some of them are Civic or CRX motors.

Part numbers or not...is it wise to swap to the lesser mass pulley?