I have a 350 ZZ4 engine with a Weiand 144 CID supercharger and MSD 6AL ignition box, Pro billet distributor and 8.5 mm spark plug wires. I am changing the spark plugs and I need to know a good brand spark plug and a recomended gap size with those mods. I have many other mods but I don't know if they are relevant or not. I don't want too hot and violent of a spark because I already have the MSD and I don't want to kill the piston. Can anyone recomend a spark plug and a gap size?? Thanks

Nick

 

tr5 gapped at 35

 

The TR-5 & TR-55 are the same heat range with the 55 being designed for a larger gap. Use the TR-6 at .035 to .040 & you should be ok.