Ill get pics of plugs tomorrow. used champion rj12yc, just 4 bent , other 4 ok. one of the electrodes is bent out not down??? flat top pistons, stock heads, fel pro gaskets.
- - - Updated - - -these are smashed down to threads on plug and porcelan destroyed except the one the bent outward. all are pushed to side of center pin
From everything your saying &/or the description...
IMHFO that sounds like an interference problem, maybe something foreign/broken or dropped bolt/washers/nuts whatever parts inside, your plugs aren't that close to pistons to cause that kind of damage if those parts are any good or the correct parts, in the combustion chamber or cylinder, something is drastically wrong, if your pistons or something else in those cylinders are hitting your spark plugs {
even if they were extended tip plugs}, bending the electrodes, shattering the porcelain on the plugs, bending an electrode to one side drastically {
even if they were domed pistons}, something isn't clearance correctly or you have something in them cylinders or the completely wrong plugs etc....
Hope you didn't use longreach 3/4" 14mm thread, instead of the correct 3/8" 14mm threads...
the photos below are of a 361 B-Lowdeck,
but the heads are basically in the same place & style of angle in the combustion chambers, the smaller one is of an early closed combustion chamber, I know it's not a 440 RB it's an early wedge, but it's shows the relationship of piston at TDC & the spark plug angles & clearances...
& with the
felpro gaskets they would be even father away they are 0.039" compressed vs the 0.020" steel shim gaskets stock...
your plugs will go in where the electrodes are all at slightly different angles, in different cylinders, unless they are indexed/shimmed with different thicknesses of plug gaskets to all line up at a certain direction/angle... {old racers trick}
Anyway, I'd suggest you tear it apart if you cant figure out what's closing/bending the plug electrodes...
Photos might help some
