I just decided to add a 420 Megeblower from a boat to my 71 Chevelle.
One of the things I would like to do is change from the serp belt to a 3"gilmer style for looks and sound value.
I assume tensioner wont work but dont know or have one to look at.
Anyone here done that?

I believe that you can get that info through holley now, they bought up B&M's stuff I believe

Hmmm, I have been thinking of doing the exact opposite. I have a 3" gilmer set up and would like to go serp. Wanna trade?

I have a 60t, a 48t, brand new idler pulley and manifold mount bracket and belt(new)

I would but my set has a couple of dings in it from being packaged wrong. Dont think you would want them
Pic1 Pic2

is that little ding in pic 2 a blower pulley? Is the big ding in pic 1 the idler pulley and is that all the damage?

what size are the blower pulleys?

Yes and Yes
I can look when I get home on size

ok, lemme know.