Ok, need some advice and will try to make this easy to understand. Here is my story: I bought a 1988 F250 not running. The original 460 had several bent pushrods and bent intake valves. Instead of rebuilding the top end I found a 1994 460 engine to replace it with. When I bought this replacement engine it still had the stock exhaust manifolds on it. Wanting to use the 88 manifolds because the 94 had ports for the air injection I decided to swap the manifolds, this is when I noticed that someone had JB welded 2 exhaust manifold bolts into the manifold because the 2 bolt threads in the driver side head were completly gone. In other words they were covering up the broken and unrepairable cylinder head.
Frustrated I went ahead as planned, swaped manifolds and instaled the engine because I really needed the truck soon. Truck runs, actually real well but I am just tired of hearing the exhaust leak. I have invested quite a bit of money making this truck right and dependable that I do not want to continue on with this exhaust leak like it is.
Here is the question. I still have my E7 heads from the 88 engine. I understand that there is a difference in intake valve size between the E7 and F3 heads. What I am wanting to do is some quick port cleanup work, mostly in the bowls and spend some time in the exhaust port. I will also have the intake valve opened up to the larger F3 intake valve size. Does this seem like a good idea and will it keep me close to the same performance as I am currently getting with the F3 heads? I am not able to find a pair of F3 heads ready to run and the E7 heads I have are actually good clean heads minus the bent valves. Any suggestions would be greatly appreciated.

 

If the engine was on the stand, why didn't you just drill out the broken bolts and heli-coil the heads?

 

Because the whole bolt boss is gone. There is nothing to tap/helicoil to. It is not that the manifold bolts broke in the head, it is the thread boss in the head is literally broken and nothing left to bolt to.

 

Well, the only thing I can think buddy is taking the head off, grinding it clean, filling the void with welding bead. Shape accordingly, and go ahead and mark your spot to drill then tap the threads. The only thing that makes me wonder is the hardness of the weld in relation to drilling and tapping & possible breakage. That is the only thing that concerns me.

 

The exact repair that I thought of and the exact problems that concern me as well. I have a very good friend that runs a machine shop and talked with him about the repair and agrees with the both of us. That is why I just decided to replace the heads. Now I am wanting to know if I can make the E7 heads as good as the F3 heads.