recommended plugs for 400 engine with...

[tarvin890]

time to change the plugs. i have a decent built 400 with .509 cam 352 heads msd dist and 6al box... what autolite or plug number would do well with this combo? unless autolite has been replaced with a better plug on mopars these days.... thansk for suggestions.... timing recommendations?:toothy1:

 

[tarvin890]

wow no one has input on this? heat range all that good stuff?

 

[RustyRatRod]

Use the Champion number for the stock 400.

 

[moper]

I like Autolite 85s for iron headed big blocks. With a .509 you might want to go one heat range hotter though.

 

[gniknayrb18]

if your using an msd box i have been told to gap the plugs you get to .40-.45

 

[stroked340]

Autolites run them in everything i own i believe the part number for you should be 85's..i wouldn't run champions in anything..

 

[383Scampman]

Autolite 85's set @ .035" for standard ignition, .045" for MSD, .055" for D.U.I.

 

[tarvin890]

Use the Champion number for the stock 400.

chumpion plugs in a chrysler? surely you jest...

 

[tarvin890]

thanks to all... we have reached concensus...autolite 85 or 1 heat range hotter. 40 gap and timing at 36

 

[RustyRatRod]

chumpion plugs in a chrysler? surely you jest...

That's what they came with. That's what they recommend.

 

[twayne24365]

We have always run champion plugs, no problems yet

 

[RustyRatRod]

We have always run champion plugs, no problems yet

Exactly. Been turnin wrenches since 1974. Never had issues with any brand plug. People always latch onto the stupidest of myths and rumors and take them as fact.