deadeyejedi

i recently changed the plugs in the 76 455 .ac delco r46sz .the parts store didnt carry the r46sx .and i mistakenly gapped them at .080 as per spec for the sx plug .the sz requires a .060 gap .should i pull them and regap ?i have no idea what the difference between the two are .i also advanced the timing to 16degrees btdc it was at 14 .the engine runs real good now but not sure about the gap thing. im assuming one plug is hotter than the other ,any help would be appreciated ,thanks

deadeyejedi

while were at it does anyone care to look over this pic and point out any issues they see .it looks to me like some of the vac lines need rerouting ,and the egr valve is plugged off ,thanks

Sugar Bear

The last letter refers to the gap. IIRC there was a service bulletin in that era that said to reduce the gap due to hard starting in very cold weather. My preference would be first, to get the correct plugs and gap them correctly or second, gap the new plugs to the tighter specification.

You could be overworking an older ignition system with the wider gap leading to problems such as burning a rotor or shortening the life of the ignition coil. Should have no effect on anything on the low voltage side of the ignition system.

Either way I don't see this as an urgent problem.

svnt442

The gap was an experiment for emissions and all it really does is over stress the coil. I have always gotten the plugs for a closer gap and gapped them at .045 and the cars have always run fine. There is no need for an .080 plug gap in my opinion.

Fun71

I second this opinion.

deadeyejedi

Thanks for the replies I'll pull them and regap to .060 as per the specs at some point I'll be upgrading the distributor .

oldcutlass

It should already have an HEI, no need in my opinion to change it out.

Olds64

x2

deadeyejedi

i does have hei but at the least im going to change the cap rotor and wires engine skips a tiny bit and has a slight stumble off the line no telling when any of this stuff was changed

Sugar Bear

Try disconnecting the vacuum advance to see if the stumble goes away. If it does the pole piece in the distributor is failing.

deadeyejedi

thanks will do