Hi gang,
I'm dropping an HEI in my motorhome that has a 402 and oval port heads. I don't remember the casting numbers as it's been several years since I've been into it that far but I picked up a good HEI to replace the stock points type distributor. Anybody wanna spec a spark plug for it? Thanks,


Cam

I used a 45 gap XLS plugs for a few years with no problems with my stock HEI.

What year is the 402? Stock heads? I only ask because if you are using 70 or later BB heads you will need the taper seat plugs like the r44t or 43t if your motor home mill is a hot one. ;) The XLS plugs are gasketed and used on 69 and earlier heads. I would start with 44's or an NGK or autolite equivalent, like an autolite 25 and adjust depending on how the plugs read after some runtime

Thanks guys,
It's a 71 motor/heads and does use the tapered seat plugs. I'll try a 44 or a 43 then at .045. Thanks

Cam