Engine build /compression question combination
10-31-2013, 09:29 PM
#14
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I have 548 ci blocks bore 4.5
Merlin heads 30630 119 cc 2.3 and 1.88 valves
je /src pistons #257943
crank 4.25 stroke
rods 6.38
The compression ratio appears to be 8.5 to 1 is this correct? if so or if not will I need to change out the pistons?
The plan is to put a dart intake and carb ...the one that came on the 500 carb engines...(not sure what size to use)
and a a hyd flat tappet cam in it (dont want rollers due to price) dont know which one to use
I'm looking for input here what hp would these be? I'd be happy with 500 to 600 hp as the boat origionally came wit 500's and ran 88 (dont want to pop the bravo's 88-98 mph is good for me)
I was looking at the merc website looks like the bulldog is aprox 8.5 to 1 also
is this a viable build? im trying to save what I can and not put the wiand 250 blowers back on
I would like to keep in the low octaine fuel due to not knowing what you get these days
hope this makes sense with what I am asking
Merlin heads 30630 119 cc 2.3 and 1.88 valves
je /src pistons #257943
crank 4.25 stroke
rods 6.38
The compression ratio appears to be 8.5 to 1 is this correct? if so or if not will I need to change out the pistons?
The plan is to put a dart intake and carb ...the one that came on the 500 carb engines...(not sure what size to use)
and a a hyd flat tappet cam in it (dont want rollers due to price) dont know which one to use
I'm looking for input here what hp would these be? I'd be happy with 500 to 600 hp as the boat origionally came wit 500's and ran 88 (dont want to pop the bravo's 88-98 mph is good for me)
I was looking at the merc website looks like the bulldog is aprox 8.5 to 1 also
is this a viable build? im trying to save what I can and not put the wiand 250 blowers back on
I would like to keep in the low octaine fuel due to not knowing what you get these days
hope this makes sense with what I am asking
Aluminum 310cc heads Pro comp
cam is 114lca, 234/[email protected] .578 lift
Dart style intakes
800cfm HP500 carbs
made 598HP@5200 and 660TQ@4200
after redoing some things I think I have more hp now due to the boat running faster then I thought...its very mild for the CI... if I built them I woulda went with more cam and for sure the carbs and made 700hp.... when I redo them I will....
11-01-2013, 08:08 AM
#15
I am 547CI 9.2:1
Aluminum 310cc heads Pro comp
cam is 114lca, 234/[email protected] .578 lift
Dart style intakes
800cfm HP500 carbs
made 598HP@5200 and 660TQ@4200
after redoing some things I think I have more hp now due to the boat running faster then I thought...its very mild for the CI... if I built them I woulda went with more cam and for sure the carbs and made 700hp.... when I redo them I will....
Aluminum 310cc heads Pro comp
cam is 114lca, 234/[email protected] .578 lift
Dart style intakes
800cfm HP500 carbs
made 598HP@5200 and 660TQ@4200
after redoing some things I think I have more hp now due to the boat running faster then I thought...its very mild for the CI... if I built them I woulda went with more cam and for sure the carbs and made 700hp.... when I redo them I will....
I agree with others about going full roller on the cam setup - it is just a much more reliable way to go, in light of today's situation with flat tappet cams. Plus, you have the opportunity to get that valve up off the seat much more quickly, which really enhances midrange power. Keep in mind that high lift, high velocity cam profiles mean spending the extra money to buy the best valvetrain components that you can afford - that means high quality lifters like the Morel's, hefty pushrods that won't flex and create bad harmonics, and good valvesprings that will hold up to the abuse.
