I think the 70 Chevelle big block (402) should have a deep groove pulley on the alternator by my searches. Anyone have a picture of what it looks like. I ordered one and it is different looking then what I thought it was going to look like. It's flat on the front side and about twice as heavy as the one that was on the alternator when I got it. The alternator I have is dated coded for a 70. Thanks for the help.
Ray

I don't know but I've always heard the 402's didn't have the deep grove pulleys.

I assumed by what I read that all big blocks did, maybe only the 454 engines. So what is the correct pulley for the 402 application? Since I did have a correct alternator on the car I purchased two years ago I have nothing to compare.

As far as I know it's the same pulley used on all GM vehicles of that vintage.

I was always told that you could tell an LS6 by the deep grove pulleys that the other big blocks didn't have.

If I already have the deep grove pulley, I would use it.
Sounds like you have the correct pulley for an LS6.

What color should the pulley and fan blade be on the alternator? I've seen silver and a gold color for the 402 Chevelle.
Ray