This conversation started over on my Best way to make 600hp? thread, but I thought it deserved a thread of its own.

Who can give the skinny on Mercury motors over the years? Displacement, horsepower, years used, and any other information that might be useful. If we get enough responses, I'll throw them all in a spreadsheet and put it up on the web somewhere. Might help someone when they are shopping for an older boat.

"Calling all oldtimers"
Hey, I think he's talking about me!
Gary

Let's see, for the Mark IV, Gen V carbed 454s

330 TRS 1977-81 Merc Trans
330 TRS 1982-87 BW Trans
370 1979-87 (predecessor to 454 Mag)
454 Magnum (7.4 Magnum) Alpha 1986-88
7.4/330 1988- Bravo
340 inboard 1981-1987
454 Magnum (365hp) Bravo 1988-97
400 cyclone 1980-86
420 & 425 1987-93
475 Turbo 1981-85
525SC 1991-96
450 (roller cam) 1995

If anyone cares about the HP smallblocks ,
here's a few.

280 TRS 350 c/i of the 70's and early 80's

300 Tempest 350 c/i 83'-86'

320 EFI 350 c/i 87'-89'

377 Scorpion/ black scorpion 377 c/i 96'-04'

Dont forget the 86 collection

MCM 400 Cyclone

MCM 420 became the HP 420

MCM 440 Cyclone

MCM 460 Cyclone which was a 468 cu/in

and the

MCM 575 became the HP 575 was a 540 cu/in Had solid lifters

I believe (at least I am pretty sure) the Merc 460hp, had a 4.25" stroker crankshaft which made it a 482cid engine.

Yup, being old screws with memory. It was a stroker 482. Thanks Mark.

Does anybody remember the 482's from the 1970s called the "Tornado" It said "Competition Powerplant" on the sticker on the valve cover. I think these were 12:1 motors we used in Open class. We could bore them to 496's and still stay under the 1,000 cu. in. limit we had back then.
I think we were getting 680 hp at 5,200 RPMs, where we ran most of the race. Then, after we burned off some weight, I would kick them up to 5,700 if we could improve our position.

Those were the days!

There were two different 400 engines available, the 400 and the 400 Cyclone.
400 had stock rockers with stamped steel valve covers while the 400 Cyclone had roller rockers with finned aluminum covers and Cyclone tags riveted in the middle.

This is awesome information. Thanks for sharing all !!