Hello,

Have a plug gap question; and unfortunately not alot of information. But I am hoping someone has the experience to make a good judgement call. Have a 1990 L98. Motor was recently rebuilt by my engine shop. Stock bottom 350 with new bearings, heads are the Corvette L98 heads that have been ported and polished. Valve job, new springs, lighter pushrods, 1.6 roller rockers. Cam is a stock 1990 Corvette Cam, that has been tweaked. The guys who built it are pro's but they are old school. Rather than plugging in a new cam they degreed the old one different to move the powerband up. Will be running a TPIS 1204 Intake,.... if I can find one for sale in the near future. MDS 6AL Ignition on a Jegs Distributor with a blaster 2 coil. Car originally called for FR5LS copper plugs. Engine is supposed to make 420Hp. I jumped down to FR3LS copper delco's (2 steps colder). Where do I set the gap?


Thanks,
Dan

 

.040 is a good baseline.

 

Agreed. That's my default for most N/A setups.
Since you have the more powerful CD ignition, one could argue that it will handle a .050" gap or more, but it wouldn't make any more power, just a tiny improvement in idle quality/emissions.

 

Yes.

You should DEFINITELY have some gap.

On the list of things that REALLY MATTER, how much gap is somewhere between about #173 and #452.

.040" is fine. .035" is fine. .045" is fine. Any more than that, all you accomplish, is stressing the other high-voltage components (wires, cap, rotor) unnecessarily. Any less, gets too easy to foul.

So, yeah.... make sure they have some gap.

 

Thanks! .040 it is