Head sensor?

I'm using a set of older heads for my 85, the problem is the holes for the sensors in the heads are too big for the stock sen's. Anybody know if there is a adaptor that will work or is there a larger sen available?

NPT reducers, I think 3/4 to 1/2

thanks, I'll check it out

Most of the TPI sensors are 3/8"NPT
The large holes in head are same size as the heater outlets on the intake; 1/2"NPT

http://www.summitracing.com/parts/RUS-661580/
http://www.summitracing.com/parts/EAR-991204ERL/

Thanks, now I just have to figure out how to get the frozen plug out of the head with the broken extinsion stuck in it:suicide: