I'll just cut to the chase:

I am trying to put aftermarket aluminum heads on a 70's era 350 SBC. The head guide pins are the correct size, as they will fit into the heads on one side, but wont allow the head to go completely on. I can put the head on the front one if the back one isnt in, and the same with the other side. It seems that the dowel pins are just a hair too far outward to allow the heads to fully set on the block.

Can I file the ends of the dowel pins down until the head seats to the block?
Should I drill out the holes in the heads to allow the pins to fit that way?
I have heard of offset head dowels, but I do not know how to install them?

Any and all help is appreciated!

I wouldn't touch the block, either modify the dowel pin(grind some off, bend it a little, whatever works) or remove the ones that won't go in altogether imo. They aren't exactly necessary to have, just makes putting the head on a lot easier..

Pretty typical of the QC levels and tolerances, on both counts...

Let me guess: Skip White? Patriot? Pro Comp?

Probably not far enough off to need offset dowels; after all, that block has been having heads installed on it, off and on now, for the better part of 40 years. Can't be too drastically wrong.

Yeah just file the dowel pins down until they fit. Shouldn't take much. Don't modify any castings.

Then if you ever get heads that are machined correctly, you can just replace the dowels.

Thanks guys, I am just going to get a hand file and file them down until the sit on without resistance.

Yes they're Procomps. lol