Is there a difference between an auto 455 and a marine 455? Is the boat application different? If so, which is better????

 

No difference engine wise, some of the marine engines came with Ka heads which are very good heads and they also came with 4-speed flywheels and the cranks were usually drilled for for 4-speed transmissions. If it is currently in a boat you will most likley have to change the oil pan and maybe add a water pump dependiing on how it was cooled.

 

Same carbs also?? I recently got a 7042250 carb that had the hit idle compensator removed and lead shot put in its place... I thought maybe it was from a martaine or special epplication...

 

Marine carbs are always modified to prevent any fuel from spilling out onto the intake manifold. This includes modifying the throttle shafts and changing the j-tubes on Holley's. Distributors, alternators and starters are also different to prevent sparks in the engine bay.