I've seen .080" specified, but I wouldn't use that. .055" is what I use for low compression; an HEI can certainly support a larger gap than points. Bruce Roe
22 Dec 06 11:09 "Dave Wyatt" <[EMAIL PROTECTED]> writes: > My son runs a HEI in his Cutlass. Started out with a 307, then a > 350, and > now finally a 455. All with the same distributor with MSD > internals. At > one point we tried gapping the plugs to the recommended gap, but the > car > slowed down a bunch. We ended up with the plugs gapped at .030 to > get the > performance back. > > IIRC, The large gap was an emmisions band aid to get a larger spark > in low > compression and poor fuel. Your 425 may not like it. What gap is > recommended for the transistorized ignition in '67? I'd use that > number for > a stating point, since the HEI is just a modern version of that > system. > > Dave Wyatt
