Anyone used them they are cheap at Jegs.....like half what March wants ?

WM4000...prob exact dimensions as March 4000.............?

 

Either Hot Rod, Super Chevy or Chevy High Performance did a spot on the march underdrive pully's to see if they really were worth a gain in HP. I don't remember which, but I do remember the results.

They gained exactly 3 HP over 6000 RPM, from Idle to 6500rpm, vs. the stock set up, so I wouldn't get them, it's not worth it. They look good, but definitely not worth the "power" gains they say you'll get.

 

Not what I have read on the web. Search and you will find multiple dyno tests showing 6-12 hp at the rear wheels.

So for 50 bucks its worth it and easy to do.

 

I'll dig up the article, hopefully I found it online and not in one of my magazines that's on my shelf. They baselined the motor, then used the same motor, only difference being the pulleys. Either way, they were emphatic that it wasn't worth getting based on the money spent on them.

--edit---

Quich search is pulling up what you're saying, I just remember the dyno chart and the results being really low and not worth the cost. I'll keep digging. I'd baseline your car on a dyno "Before and after" to see what you really get if you go through with it. I'd like to see if you get the advertised gains out of it.