Penta 280 Advice

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cavitat

Recruit
Joined
Dec 3, 2011
Messages
1
I just bought a Penta 280 with serial number that ends with D. I'm told this is a ratio 2:25...for a 4cyl motor. My problem is that I am having a V8 small block 350 given to me. The boat is a cuddy 18.5' with a deep ocean hull. It's loads of power which I don't really intend on using (top-end) since there's tons of debris in our waters (Vancouver). What are my options with this Penta 280 D leg at a 2:15 ratio and a V8 350 short block?
 
Don S

Don S

Honorary Moderator Emeritus
Joined
Aug 31, 2004
Messages
62,321
Re: Penta 280 Advice

You were close, it's a 2.15

You need a 1.61 for your V8.

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billbayliner

Chief Petty Officer
Joined
Jun 30, 2006
Messages
553
Re: Penta 280 Advice

the D on the transmission tag is the designation originally asigned to the drive . the b c and d transmissions are the same reduction.
the lower may not be the D ratio if it had been changed . remove the prop and ring anode. the actual overal ratio will be stamped in the carrier unit. use a wire brush and see what it is.
Like Don says you need the 1.61:1 lower. you need the brg race with it and it must be reshimmed also.
 
P

peejcj8

Petty Officer 2nd Class
Joined
Jan 8, 2006
Messages
102
Re: Penta 280 Advice

So just for my common 280 knowledge,

The ratio is determined in the lower, and the uppers are the same for all three?

Eric
 
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billbayliner

Chief Petty Officer
Joined
Jun 30, 2006
Messages
553
Re: Penta 280 Advice

That is correct. it's an overall ratio, and does take into acount the reduction of th e transmission.
 
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