ZL-1, MSD

[69SSZL1]

My ZL-1 engine "loads up" when idling or driving in traffic (cruise night only). Would an MSD unit (I would use the GM version 10037378 if compatable with TI ignition) help this problem? Engine is all ZL-1 including cam, carb. Thanks.

[Chevy454]

No...what plugs you running? Also, how is your carb set up?? Your powervalves in good shape???

[69SSZL1]

Plugs are stock AC-R43XL, carb is stock Holley 4296 set up, power valves are good, cam is stock ZL-1 with 260/270 @ .050 duration.

[Chevy454]

My first suggestion would be to ditch the AC plugs and try a set of NGK v-power plugs...if they don't clean up your idle, then you can definitely look elsewhere.

[69SSZL1]

Thanks, those are great plugs.

[COPO]

Rob what are the NGK plug numbers for an L-72?

[Chevy454]

In our 840 heads we run the R5671A-7, and I believe we run the UR5 in our 291 heads...