Search results for query: *

If you like NGK plugs I would try these NGK R5671A-9 if using dome pistons. R5672A-9 for flattop pistons. These are 5/8 hex 14mm thread. 3/4 inch reach plug. which I believe is correct for stealth heads. (same as E-brocks) The -9 is the heat range. The higher the number the colder the plug for...

This is problem I had. My 383 was sucking oil through the valley pan. And like Moper said even a small amount of oil will cause detonation. Thats why I asked about reading the plugs, try to find signs of it burning oil.

What kind of spark plugs are you running? How do they read? Are they fouled? I am going through a similar problem with the 383 in my Road Runner. The problem ended up being a vacuum leak in the intake valley pan. Recheck yours carefully. Does your vacuum guage hold steady at idle or is it moving...