replace 0331 head with 7120 head

[dwg86]

I know I have asked this question a while back, but with more strokers being completed, I thought maybe someone has ran into this. I am replacing an 0331 head with a 7120 head. its going into a 2003 Jeep wrangler. It looks like the 2001 and later Jeep Cherokee has the same setup. The 0331 head has the idler pulley mounted to the head. The 7120 head doesn't have the hole or boss to put the hole. I was going to drill and tap a hole in the front of the head. The hole will go into the area where the foward pushrod goes through the head. This will not interfere with the pushrod.I figure since this area is not pressurized, some RTV should seal the threads. My head is at the machine shop, and I was going to have them put the hole on the head so it's straight. I'm affraid if I do it I'll get the hole crooked and the belt will come off. Has anyone ran into this problem yet? If so, what was done to fix it?

[dwg86]

OK, I guess I'll be the guinea pig. I took the cracked 0331 head for a pattern to have the idler pulley hole drilled in the 7120 head. My machinist thought there was enough material (strength) to drill and tap a hole. I'll post some info when I get the head back.

[SilverXJ]

I've never replied but people with TJs with the 0331 head drill and tap a hole for the idler pulley on the 0720/0630 head. Having the machine shop do it is the best idea.

[dwg86]

Thanks Silver