4.3 GL/OMC spark plug help

[Hammond74]

Hey guys , and gals ..... noob here, hoping someone can help me out. Just had my 4.3 Volvo/OMC fully rebuilt. I’ve been searching on here and googling trying to come up with what are the correct spark plugs to put in it. Seems to be several different answers and with these answers come a lot of variables on thread depth , reach etc... just put a new distributor on yesterday which is the Delco ..... again any help would be much appreachiated

 

[QBhoy]

Ngk BR6FS are the standard go to plug for most carb GM 4.3 engines.

 

[Scott Danforth]

assuming your motor is a 1995 or older, the NGK's listed above

 

[Hammond74]

Sorry thought I included that info .... 1998

 

[Scott Danforth]

1998 should be vortec heads - confirm it. vortec heads have 8 intake manifold bolts vs 12

AC-MR43LTS or NGK BRP6EFS

 

[Hammond74]

Thanks Scott , yes it is the vortec heads and that’s what is confusing me. It had been running NgK BR6FS .... with just a quick glance at the 43LTS , they appear to be almost double the thread depth ... which made me a little nervous and cringe with the thoughts of turning it over after what I spent on the rebuild and hitting pistons !

 

[Hammond74]

Guess will just have to turn over REALLY slowly
And gapped at .040 ?

 

[Scott Danforth]

if your running short plugs in a vortec head, the electrode would be burried about 3/8" up the plug bore. while the motor would still run, you will be significantly down on power. if that is the case, you will also need to clean the threads

stick your head down there, look in the plug hole with a flashlight.

its not rocket science