I had a pyro gauge years ago, my Gauge went bad so I took the pyro out and inserted a plug. Was trying to get the plug out tonight and managed to mangle and round the head. Would there be an issues tapping the manifold 1/2 to 3/4 inch away from the current plug and placing the new pyro sensor there? Would it weaken the manifold and cause it to crack between the two holes?

 

i have two holes in mine but they are on opposite sides of the center divider just above turbo to read 3 front and 3 rear cylinders. not sure about that close together, may weaken manifold.

can't you helicoil the plug out? i would put a little effort into that before drilling another hole personally.

 

A helicoil will put threads back in a stripped hole, but he has to get the plug out first.

I'd just drill through the plug and retap, tapered threads are more forgiving than straight threads. Start small and center punch center, you want to stay as close to center as humanly possible.

 

I'd try heating the plug to a dull red and use a Snap On reverse socket. Made to tighten down on the stripped head and they are designed especially for just this problem. Next time use a dab of copper anti-sieze paste on the fitting.

 

stock manifold?