short ngk or ac delco plugs?
 

I have a 1970 355 mild built with gm 882 heads I'm looking for an acdelco or ngk plug with an equivalent length to the accell shorty plugs for headers. I would prefer a plug in a heat range comparable to the ngk #6 or #7... probably 6. 7 may be too cool... according to what I've seen. Is there an issue with to cool? I know too hot has many problems.

I know plugs is covered a lot but I've searched and can't find a definite answer.

Thanks.

Re: short ngk or ac delco plugs?
 

I am running rapid fire ac delco platinums with headers and doing perfect. I have them in 3 older vehicles 68 Buick 350 70 chevelle 396 and 72 454 all with headers no clearance issues and smooth running.

Re: short ngk or ac delco plugs?
 

Are they as short as the accell shorty plugs tho? My clearances are tighter than I'd like and wanna free up some space but also wanna stick with delco or ngk in that heat range