Looking to learn some here, What is the difference between these two besides the 256cid Holley/ weiland, and compression ratio?

Are their differnt internals, heads, cam, springs,??

Thanks

here are the specs for the 500 EFI

http://www.mercurymarine.com/hp500_efi_-_470_hp

and the 575

http://www.mercurymarine.com/hp575_sci_-_550_hp


This might help alittle


Travis

Traviss,

I went through the specs and only diff it lists is as follows

575= TBI, comp 7.50:1 and weiand 256, 92 oct required
500= MPI, comp 8.75:1 87 oct required

I am really curious is the blower the only differance?? their has to be more to justify the cost??

Boating magazine had an
article on building the 575,
i will try to find it when i get home
tonite, but some of the differences
I do recall were: 575 flat tappet
hyd. cam, the already mentioned
compression difference, and shorter
connecting rods ???

With mercury marine horsepower
is exponential with $$$$
jt

Oh yeah, the oil filter screws on an additional 1/8 of a turn on the 575. That oughta be worth some $$.

The 575 is a hand built blueprinted motor while the 500EFI bottom end comes preassembled from GM powertrain like the rest of the black Merc motors. Im sure they justify some of the cost from this fact. Still pricey though.

Ron