AC DELCO MR43T, crosses to NGK TR5

Old-school name, still slaps. The AC Delco MR43T is your tried-and-true spark thrower, built for small blocks, big cams, and folks who think EFI is optional. Crosses to NGK TR5 if you’re the mixing-and-matching type, but this one’s got that GM muscle vibe baked in.

If you know, you know. Gap it and grip it. Add to cart before your old plug says, “I’m out.”

Fits 1996 and older MerCruiser and Volvo Penta 5.0 and 5.7 engines