oil passage to head with ARP studs

[kirkallen143]

Howdy,

I was just reading the sticky and wondering if anyone had to/has enlarged the oil passage hole at the rear of the block when using ARP studs?
Anyone know how far is too far when enlarging the oil passage?
I was thinking about just drilling the hole in the head out to 1/2" or maybe 9/16", what do y'all think?
Need to figure the diameter of the late '70s tapered bolt compared to the size of the oil passage now, good starting point. Appreciate it fellers.

Kirk

 

[Anonymous]

Don't go too far, if the passages are too large you could actually louse oil pressure to the head and not realize it. See Simon’s post under the Rocker Arm Shaft Oiling hints sticky.
http://fordsix.com/forum/viewtopic.php?t=29111
He provides a good step by step with pics that tell the story. For me, after re-establishes the oil transfer slot on the head deck surface, I’m using a tapered head bolt from a '75 - '83 and on 200/250 to accomplish the same thing.