Was wondering if anyone knows the dia. of the headbolt holes in a 351W head? Also, if anyone knows the bolt spacing pattern for the head. Can't seem to find this info on the net anywhere.
Thanks, but maybe I should have phrased my question a little different. How much would you have to open up the holes in a 302 head to use on a windsor?
I mic'd the 351W ARP bolts that I have and they where 0.499 which isn't going to fit in a 1/2" hole... Typical machine design practice would have a 1/32" clearance on the OD. So the hole would be 0.531 (17/32). Was wondering what Ford deemed acceptable for clearance. If it was a 32nd, a 16th, etc.
If no one knows I suppose I could measure the holes in my 302 heads and figure out how much clearance they provided for the 7/16" bolt
Thanks!
< Message edited by 68Bronco -- 5/12/2008 9:57:25 AM >
"3. Since I was using 289 heads, I had to drill out the head bolt holes for use with the larger bolts. 1/2" seemed a bit tight for the ARP bolts, so I went back to Travers and purchased a 33/64" bit to loosen them up a bit. a 17/32" would have worked as well, and could have been purchased locally. You MUST use a drill press that can keep the head level and straight for this step."
Guess it isn't all that critical. Thanks for the replys though. Suppose I'll go with the 17/32" and it on the mill to get it fairly accurate. Which brings up the second question. Anyone know the spacing between the holes? Figure I can square up the head to the table and use the digital readout to speed up the process.
Thanks again,
< Message edited by 68Bronco -- 5/13/2008 9:18:14 AM >
I went 17/32" on my GT-40P's. I didn't want to go larger and risk the heads walking at high revs with high compression or boost. Don't know if that's a real concern but I've seen a lot stranger things happen.
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351W headbolt question - 
