differance between 365 and 420's
#14
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The Cyclone engines were 370/400/440/460HP versions. They all got the same 737-5536T piston, except for the 460HP version.
Alot of these questions can be answered, by looking at the parts diagrams and drawings on mercruiserparts.com
Last edited by MILD THUNDER; 03-23-2014 at 09:59 PM.
#16
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Wonder where the hp420 gets its comp bump from .I'd swear they were built like " mini hp500's' been a while since the '80s though .going to have to check da books tomarrow now curious
#18
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Most guys assume a merc rect port head is the same from a 454 mag, to a 800sc, but they were assembled with different components per application.
#19
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Could be indeed ! Don't have 420's (I still reference them to the mini hp500's ) rolling through these parts much .do know for shure the 502 versions get a little xtra dome on the hp500 . And roller rockers on the 420hp
#20
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i believe the compression ratio on the 415 hp mpi engine and the hp500 are both 8.75/1.