Drill AFR 165 heads for 1/2" studs
Has anyone enlarged the head bolt size on their AFR 165 heads from 7/16" to 1/2"?
I have a ford R-block(1/2" head bolt threads) 331 that I am scaling down to a milder setup.
I took off my AFR 205s and thought my 165 were 1/2". Ooops.
I found one thread about somebody asking if they could do this, and as usual there was no closure on the thread.
I will talk to my machine shop tomorrow about this.
If I had to do it myself, I would true up my drill press and first use a step drill that has a 7/16" to 1/2" step. Then I would use a 1/2" drill to drill thru the head and open the hole up. I would finish with a 17/32nd drill bit and go thru again.
The idea is that the step bit starts the hole true to the 7/16" hole. The 1/2" uses that hole to start straight. The 17/32" is what the holes in my heads that use 1/2" bolts/studs are actually. So I would give a pass to clean up down the 1/2" hole and all should be good if everything stayed true.
Perhaps I should skip the 1/2 and go straight to the 17/32?
The thread I was looking at made this sound like it should be easy.
It scares me to take my expensive heads and chop like this.
This motor is going into a 62 Jaguar MK2 with a tremec 5spd.
It should be fun and a real sleeper. Car will be just under 3000 pounds.
63.5 Galaxie 500. Outa this world!
Last edited by selash; 03-09-2014 at 11:22 PM.