Hot Rods Spark plug choice

Hi, I'm near the end of the 283 rebuild for my 66 C10 and need some plug advice. The original power pack heads were junk so I used some 416 305 heads that I had. I never gave the plugs any thought until I went to put the old ones in so I could paint the engine and they wouldn't fit! I prefer to use an AC plug but am open to suggestions.

FWIW my mild build is the original 283 .030 over, Edelbrock performer intake and 204/214 cam and 390 Holley along with the 416 heads.

 

I would try R45TS.

 

Thanks, I'll check that out.