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Swapping out a 470

T

tobra100

Member
"I can pick up an 1981 cast ir

"I can pick up an 1981 cast iron 4 cyl mercruiser, complete, including both sides of the transom. (everything but the out drive. Can anyone tell me if this is everything that I need. also someone told me that my 170 alpha drive may have the wrong gears, Can anyone tell me if this will be an easy swap?"
 
well ray to start nothing is e

well ray to start nothing is ever easy swap are you talking about a 81 470 and what gear ratio is your alpha
 
"I dont know the gear ratio, b

"I dont know the gear ratio, but its the drive that came with it. Do you know how I can find that out."
 
"On the port side of the outdr

"On the port side of the outdrive should hopefully be a sticker on there will be some numbers, should be a serial # and Drive ratio, something like, 1.98:1R, 1.80:1R 1.65:1R etc.."
 
"Brian, is it possible that th

"Brian, is it possible that the numbers are 184R?
That was best read.. if that cant be right, ill have to use a magnifying glass Ray"
 
"yes, definatley could be 1.84

"yes, definatley could be 1.84:1R, should have no problems with the 1.84R with your swap. As far as what you need for the swap that would depend on what you have. Shouldn't be an issue going from the 470 to a 170, you really should get a manual."
 
ray as far as the engine swap

ray as far as the engine swap it shouldnt be that bad but its those little tricks to the trade that always gets ya also there are alot of things along the way that you need to change while your at it just because you are right there and they frequently go bad plus the re sealing and lining up the engine and drive so it sounds like you are really into this so get you a manual and give it a whirl and im almost positive between the manual and this forum you'll get thru it. P.S Ya gotta get it started before you can get it done just kiddin
 
Isn't a 1981 cast iron Mer

Isn't a 1981 cast iron Merc 4 Cyl at most 140HP? If so your drive ratio should be 1.98:1R for optimum performance and efficiency. Depending on the load of the boat you may be able to prop it but it may be a stretch. Just something to keep in mind.
 
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