Re: spark plugs?
 

The Autolite 133 is a .460" reach, non-projected, tapered seat plug, which crosses to an NGK R5673-8 (3249)...so that should be an exact match. Did you index the plugs by any chance? Also, I was thinking the 186 Z heads used a gasketed seat plug, no?

Here's the chart: click here Do I have the seat type wrong on the small block stuff?

wheelhop: we run the R5671s in all of our 840 headed stuff, and the engines love them...you could try a GR5, which is the standard plug version of the R5671, except it's gonna have the extended tip.

Re: spark plugs?
 

Thanks sam i will try them.

Re: spark plugs?
 

now i have the NGK 5637-8 (3249) short tip and runs great.thats what it was sam it had the long tip.but if this plug gos away i will try the AC-R44. thanks all
ps please not that word index it takes 2 hours on the race car for that.

ASTA

Re: spark plugs?
 

Thanks Rob, I'll give them a try