Marine application 454 for conversion into K5

[alaskanbowtie]

I have found a 330h.p. 454 long block in the crate for cheap and am wondering how it will perform in my K5 with new intake carb and headers ? Also can I get 400 horse or more out of it if I put aluminum heads and a decent cam ? Are the marine application big blocks built stronger on the bottom end ? Better crank or rods than standard ? All info appreciated

 

[Seventy4Blazer]

i think marine motors turb backwards.... but i could be wrong. might need a new crank and cam for it.... at the least.
Grant

 

[xrm]

it doesnt turn backwards. but you will want a new cam boat engines peak HP @5300 rpm's. I'm a mercrusier tech (over 20 yrs) my K-5 has a merc 350 with a high energy truck rv cam merc distributor and carb. been running awesome for over 170,000 miles still turn's the bfg 33.5 x 12.5 good and gets good gas mileage when i let it


ps anybody need some axles have a extra set from a 89 k-5 with 60,000 miles on them Cheap they gotta go im moving

[email protected]

 

[cbbr]

I think that the answer to "does it turn backwards" is maybe. Make sure before you buy it. It a dual engine boat, one will be reverse rotation to offset tourque steer.

Because the engine you are looking at is in a crate, I would take the serial number, model and anything else that you can find identifying the engie to a Mercrusier or Mercury engine dealer and just ask. THey can also help clear up other questions you will have such as starter location, Oil pan fitment, etc.

If there is not one near you, PM me the s/n, model and whatever you have and I will ask my Dad about the RR. He owns a Merc. dealership.

 

[ryoken]

if the intake is off, its simple to check for a counter-rotater. just look thru the front holes in the lifter valley, if it has a chain, its a standard rotation motor. if its gear driven, its a counter-rotater...

counter-rotaters are becoming very rare... it's usually taken care of in the gearbox these days.... btw, counter-rotating camshafts are worth a fortune these days.... replacements run $600 to $800.

bottomend will be stock GM stuff.. just typical marine stuff, brass freeze plugs, marine profile cam, dizzy, carb.....

 

[cbbr]

I called and asked. Got the same answer. Current mercrusiers are all just like any other GM engine, just built stronger and for marine applications. The Counter-rotation is in the drive. It should be fine.

 

[ROOSTR3569]

I bought the 502 Ram Jet 2 years ago, it is a marine application motor, I just needed to install an o2 sensor to keep it from running so rich. marine application is good, I can hold her to the floor all day, and she keeps rompin....hehe

 

[ryoken]

yeah, honestly i haven't seen a counter rotater in any boat newer than at least 8 yrs ago... and even then in old counter-rotaters, 90% are small blocks.. can't remember the last BB i saw.. and i do about 10 repowers, 15 to 20 motors a year..

i do see a fair amount of the counters, alot of my customers own early 80's to early 90's boats... i do know when i get long blocks these days that are counter, they hammer us because of the cam.. usually like 5, 600 more than standard..

is your dads place on the water?

 

[bigred81]

Marine big and small block usually come with forged cranks and the better rods because from the time their new till dead these motors are run wide open. Marine motors run tighter tolerances so they will last longer than your normal motor off the assembly line.

bigred81

 

[alaskanbowtie]

THX for all the replies

THX for all the help , still wondering about the head swap and cam to get more horse power . If I put a 268 extreme comp cam in it and air gap intake with 750 carb headers will it be around 350 h.p. it's rated at 330 but doesn't have a torque rating , anyone know what's a decent estimate ? THX Guys/gals .