I'm running a 1989 4.3 v6 on propane and a small t3/t4 turbo.

Original builder was running a Delphi plug from one of his racing buddies that they do not sell to the public. It was the **coldest plug they make ( heat range 1) said he could get me some for around $11 a piece.

**(correction) I spoke with David that built the buggy and I misunderstood him. It need a heat range 0 or 1 which is a super cold plug.

A few weeks ago I blew my head gasket and decided to have engine rebuilt from bottom up.

Bored .040 over

Hyperuetectic pistons

Comp can

Polished crank

Blocked deck

Full head work

Marine grade head gasket

ARP Head studs

Bumped compression up to around 9.5:1

And upgraded rest of the internals

Long story short the original plug stuck into the engine about 3/8-1/2 inch and were a very hot plug and engine builder said he could not figure out why this was done this way.

However, the engine builder recommended running a very cold plug with the turbo. As well as when I called the parts store I told him how the engine was built and he recommended a colder plug as well

Any help or recommendations would be appreciated.

Thanks