Anyone one know what the exact size the larger alignment
dowel size needs to be drilled out to for fitting the
350 heads on a 403. Most posts just says that one
dowel hole on each head needs to opened up "a little".

Also, has anyone done this at home with a drill or
should I leave this to a machine shop?

As this part was something I completely forgot about
when I had the heads done, I hate to slog the head back
to the shop if I dont have to .

Thanks,
Gary

 

I don't recall exactly but I'm pretty sure it goes from 1/4 to 5/16 inch. Did it at home with a cordless drill. Use a drill gauge or calipers to measure the locating dowel on the block to be positive and don't drill any deeper then necessary on the head......

 

Thanks for the reply.
I think I will give it a shot.

Gary

 

update:

Just finished drilling out the alignment dowel holes.
Used several sizes of bits to work up to the 5/16 and
some cutting oil. Worked like a charm.

Thanks for the encouragement!!

Gary