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Tiara Open Repowering a 1992 3300 Open
#1
My starboard Mercruiser 7.4L 454 gen 4 has finally died...likely threw a rod or dropped a valve. 2900hrs. I'm looking into repowering both mains with either crate 454's or complete drop in 454's mius trans and FWC. Does anyone have first hand experience with which route may be more cost effective? Other than replacing the oil and trans coolers and starter the other parts are in good condition. Michigan Motors sells the crate for $5K and complete drop in for $17K plus $1600 for FWC...quite the difference in price but I'm not sure what labor and yard time would cost for tearing down old motors and installing parts on the crate motor. I figure an expereinced mechanic could do that in 1-2 days?? any suggestions are welcome. Photos attached..

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#2
(02-16-2026, 03:10 PM)WOLFDAWG71 Wrote: My starboard Mercruiser 7.4L 454 gen 4 has finally died...likely threw a rod or dropped a valve. 2900hrs. I'm looking into repowering both mains with either crate 454's or complete drop in 454's mius trans and FWC. Does anyone have first hand experience with which route may be more cost effective? Other than replacing the oil and trans coolers and starter the other parts are in good condition. Michigan Motors sells the crate for $5K and complete drop in for $17K plus $1600 for FWC...quite the difference in price but I'm not sure what labor and yard time would cost for tearing down old motors and installing parts on the crate motor. I figure an expereinced mechanic could do that in 1-2 days?? any suggestions are welcome. Photos attached..

If possible, see if you can find a pair of Crusaders. They are laid out better, have fresh water cooled exhaust manifolds and were marinated from the GM truck motors.
Accessories should be the same like your starters, alternators etc.
At 2900 hrs., you got good service from your merc's. You can read about Crusaders build at Pascoe's surveyors site.

Spell check kills me. The engines marinized, not marinated!!
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cp4000 (04-07-2026)
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