454 vs 7.4
#5
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True, but earlier versions of the mag were 365 HP. The quesion should be more specific to what year since merc made so many changes over the years. They also had a 420HP 454 with TRS drives.
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Black mercs are still on the prop. If anyone disagrees with this, look at mercs website.
An exampel of this change was:
HP525EFI. 500 prop hp, then changed to 525 crank hp, when the 600sci was introduced. Untill then everything was prop hp, and the name of the merc racing engines the supposed crank hp. Ie, 900 sc/dry sump six = 850 prop hp and 900 shaft hp or 600 sc = 550 prop and 600 shaft ect.
Hope this helps.
Last edited by A.O. Razor; 02-06-2011 at 02:21 PM.
#9
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The 310 hp was prop hp. It was a carb engine known as the 7,4L that went out with the 502 mag and 454 mag when the 496 came in and replaced by the 6,2. The 330 was also prop hp. It was not untill later years (around when the 575sci went out) that merc racing rated the engines at the crank.
Black mercs are still on the prop. If anyone disagrees with this, look at mercs website.
An exampel of this change was:
HP525EFI. 500 prop hp, then changed to 525 crank hp, when the 600sci was introduced. Untill then everything was prop hp, and the name of the merc racing engines the supposed crank hp. Ie, 900 sc/dry sump six = 850 prop hp and 900 shaft hp or 600 sc = 550 prop and 600 shaft ect.
Hope this helps.
Black mercs are still on the prop. If anyone disagrees with this, look at mercs website.
An exampel of this change was:
HP525EFI. 500 prop hp, then changed to 525 crank hp, when the 600sci was introduced. Untill then everything was prop hp, and the name of the merc racing engines the supposed crank hp. Ie, 900 sc/dry sump six = 850 prop hp and 900 shaft hp or 600 sc = 550 prop and 600 shaft ect.
Hope this helps.
#10
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I thought the 330's were crank rated and were a little weaker with approximate 290 hp at prop. No? Read it on oso in several threads. Don't know for sure.
LC
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