sp and dp interchangeable?

trophy2860

Recruit
Joined
Aug 17, 2013
Messages
2
I have a 1986 Trophy with a single prop 290 outdrive. Is it possible to install a dp lower unit only (assuming the same gear ratio) on this outdrive? Thanks for any help.
 

LegacyT

Petty Officer 1st Class
Joined
Jul 7, 2011
Messages
250
Re: sp and dp interchangeable?

Yes you can. The 280-290 dp lower will bolt on. You will have to re-shim the lower/intermidiate housing bearing race when doing so. The dp has different ratios according to your engine... 2.3:1 for V6's, 1.98:1 for Small Block V8's, and 1:78:1 for Big Block V8's.
 

trophy2860

Recruit
Joined
Aug 17, 2013
Messages
2
Re: sp and dp interchangeable?

Yes you can. The 280-290 dp lower will bolt on. You will have to re-shim the lower/intermidiate housing bearing race when doing so. The dp has different ratios according to your engine... 2.3:1 for V6's, 1.98:1 for Small Block V8's, and 1:78:1 for Big Block V8's.

That,s good news...Thanks
 
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