Mercruiser swap

[MikDee]

Re: Mercruiser swap

OK, now I see that you have a 305, the easiest and cheapest and most available replacement is a pre 1985 2 piece rear main seal 350. I did this exact swap. More power, same fuel use. I got a rebuilt long block for pretty cheap, or you can find a used running truck motor. For a used truck motor you will have to change the freeze plugs to brass. The used truck engine is likely the cheapest way to go and the easiest swap. Everything from you 305 will work.

I agree, go up to the 350, you won't be sorry....
The fuel difference is negligeble....

I agree,This is all I was trying to say, before this thread took off into the stratosphere or you can stay with the 305, but why? either of these engines are plentiful, but with a 350 it will seem like a whole new boat! Besides, you have a Type 1 drive, the gear ratio should be the same for both, in the early years like this.

 

[seasalt35]

Re: Mercruiser swap

Wow thanks for all the reply's I like the idea going with the 350 , I will assume (I hate the word assume) nothing off the 305 will work with the 350? such as manifolds, carbs ? thanks again for all your help

 

[MikDee]

Re: Mercruiser swap

Wow thanks for all the reply's I like the idea going with the 350 , I will assume (I hate the word assume) nothing off the 305 will work with the 350? such as manifolds, carbs ? thanks again for all your help

Everything! off the 305 will work, the exterior dimensions are exactly the same! Oops! except the heads, they'll work but they've got smaller ports, & valves. Basically the only difference is the 350 has approx. 1/4" bigger diam. pistons.