I just rebuilt my 396, Its bored .30 over. I have all MSD set up, Cam and a few other goodies. What brand of spark plugs would you guys recommend?

ac delco or ngk for me.

Autolite,AC Rapid Fire,Splitfires,NGK,all good plugs. I think the most inportatnt part here is to have your car's fuel metering & ignition systems up to snuff and dialed in correctly with the proper heat range plug for your application which is key. Any good quality plug would work well
at that point if your dialed in/tuned correctly.

If your motor is fairly mild i would start with the stock plug heat range for that year head and go from there.

I have been using the Splitfires in my 396(now 402) with good results. I like the idea of a better more complete burn in the combustion chambers these plugs can provide without bothering to index std plugs. I use the Splitfires in all 3 of my cars with no complaints.

I remember Either H/R or S/C tested the splitfires on a 350 dyno mule and they picked up
a few ponies/ft lbs tq wihich was good but you would never feel it. But the real neat thing was they then placed a std plug in every other cylender and ran the motor and pulled the heads
which showed a big difference in how efficient the Splitfires were vs the std issue AC's.

The pistons/combution chambers with the 4 splitfires were a nice light tan and the pistons/combustion chambers with the 4 AC's were dirty/dark brown obviously not burning a efficiently. The splitfire & AC plugs were supposed to be exact equals as far a heat range was concerned so that was not an issue.

They also said the since the Splitfires created a more efficient cylender burn they saved a little fuel as seen on the dyno. This would make sence after seeing the heads off the motor post dyno runs with 4 std & 4 Splitfire plugs which burned much cleaner.

NGK also has a hybrid plug kind of like the Spltifire but is not exactly the same.

Scott