This really applies to any spark plug and head combo. When I reassembled my 350 with Vortec heads for my motor swap, I noticed that the spark plugs that I had installed awhile back when it was in my boat, didn't even break the imaginary plane between the last thread closest to the chamber and the chamber itself. The top of the electrode was probably a 1/4inch down the hole if looked at from the chamber. Since then I've seen pics of heads with plugs installed and the electrode was sticking out all the way into the chamber which seemed to me to make more sence. I've had a problem getting it to run right, which I attributed to the stock TBI and chip, but could a plug this mismatched contribute to poor performance and drive ability? I have a 454 TBI and custom chip on the way later this week, but does this plug condition sound like a recipe for continued poor perfomacne? My common sense says yes, but would just like some addition input.

 

Vortec heads requier longer plugs than traditional small block heads. I made the same mistake, luckily it was before I put the heads on. I think having the spark hidden from the air/fuel would be a problem. I con't remeber the PN# for the plugs, maybe someone else knows it, or try a search.

 

Use Champion RS12YC for vortecs

 

Hey thanks for the part number

 

Coool. Glad I read this. I'm getting my heads back this week or early next week from the machine shop. I'll get those plugs today. Thanks.

Brad...

 

FYI AC's are R44LTS

 

I have the AC r43lts's in my vortecs