How many hours on bigger power stuff?
 

What kind of hours are guys getting out of their bigger power engines? Like say between 750-1100HP.

I currently have around 80-90 hours on my current engines, that made 800hp. Being a engine nerd, I don't exactly 'cruise" them much. Lots of extended periods of the throttles buried to the dash, or hard acceleration from 3k to wot when playing around. Boat is old, heavy, and slow, so they often get run hard, trying to keep up with the modern more efficient boats. I just pulled them out, and going to be changing some rigging and adding intercoolers this winter. I plan to leak them down, and do compression tests this weekend, but they've been good, no issues, no oil consumption, smoking, etc. I am curious to see how they leak down.

Nothing fancy here. mostly old school stuff.
468ci
GM steel cranks
Manley Rods
JE blower pistons
speed pro rings
ARP main stud kits
ARP head stud kits
MLS head gaskets
Dart heads
Isky Tool Room springs
Crower 236/245 .630 lift cams
Trend .135 pushrods
Morel lifters
Crane Gold rockers
B&M 420 blowers 6lbs boost
twin 850 holley carbs
stellings headers
9:1 static compression
34* total timing

Wondering what other guys are getting between rebuilds on these types of engines? Big NA, supercharged, etc,

We are in the same # hour range as you. How many hours our engines will go before a failure is mostly a guess as we have too many variables compared to the cookie cutter factory tested Mercury HP engines. It gets down to how much risk you want to take when you know the answer isn't likely much more than.....???

friend of mine has 200 plus hours on N/A 735's and they still run like a clock, nothing done except oil changes...
but for how long more... ???

183 hours on the short blocks, new springs on one engine this spring, due to breaking drive gears twice on the same engine at 6k and over reving the piss out of it. but I do cyl head maintenance normally every 3-4 seasons = averages 70 hours. but I;m not afraid to take it over 6200 for extended runs.

I am going to be replacing my springs as well this winter. I like your program !

I have an 1100 I refreshed after a timing incident a customer had. Replaced his own lifters, timing light decided to be afu, anyway, besides the corner of the piston melted it was mint at 155 hours iirc. Bearings were perfect rings, skirts, cylinder walls, etc all looked great. In fact if it was just an inspection on a used engine mid summer I'd say run it.
Valves and guides good
Springs acceptable but were replaced
Je pistons
Carillo rods
Coated bearings .0022-.0024 rods and mains, I found this tight but can't argue with success.
Only issue we had was it had random low oil pressure. Found it had an anti cav oil pump.

Low oil pressure and tight clearances were before it was refreshed *

Did he lose a lifter at 155 hours, or was it just preventative maint? 155 hours is nice, for an 1100HP build. I like that.

I got 175 hours out of my twin turbo 572 tall deck making over 1500 HP. Solid roller cam with .710 lift. Dart 360 heads with Isky tool room springs running 265 on the seat.

That engine was a work of art! :drink: