Mercrusier898 305 swapping parts from 307

[Randy84]

Hi everyone I have a 1978ark Twain it has the mercrusier 898/305 Chevy in it.The exhaust are blown and it has a cracked head.I found a guy that has a boat with a 307 Chevy in it.My question is can I interchange the heads and exhaust from the two motors. Thanks for any replies

 

[alldodge]

Dang Randy, joined in 2013 and posted one time. Come back in 2016 with another question, least we can say your not a one and done guy.

Going to take some looking so I'll see what we can dig up

 

[flipbro]

Who knows? The heads would bolt on to a 305 yes as for the exhaust does it match what you already have. Must be an old boat to be running a 307

 

[alldodge]

BTW can you say what parts of which you plan to use? Question comes from no since looking into heads if your going to use the hole 307. So far the 305 has 60cc heads and the 307 has 70 to 84 cc heads.

Anything else you can say to help narrow the search?

 

[Bondo]

Hi everyone I have a 1978ark Twain it has the mercrusier 898/305 Chevy in it.The exhaust are blown and it has a cracked head.I found a guy that has a boat with a 307 Chevy in it.My question is can I interchange the heads and exhaust from the two motors.

Ayuh,..... Welcome Aboard,..... The heads off the 307 oughta bolt on, 'n run, but I donno how well,....

As noted, quite a difference in combustion chambers,.....

Bein' a 307, I'm gonna guess it's an OMC dressed motor, Not a Mercruiser,.....

If so, the exhaust manifolds are No good to ya, they'll fit the motor, but not the plumbin', 'n bracketry, to the drive....

 

[Randy84]

OK I have not had a chance to go look at the donor boat that has the 307 in it. I believe it says it is a 1976 model .I am needing the heads from the 307 and the exhaust to put on my 305 mercrusier 898 . The guy told me it's an omc outdrive on an Imp boat frame.This does not help me.I Was just wondering if it is worth the time and money.If these motor parts will interchange

 

[Bondo]

No, it don't help ya, you can do better,....

 

[Randy84]

Thank you That is what I needed to know .Thank you all for the quick replies. I was trying g to cut corners on parts prices.Seems like I better just get the real deal and do it right thank you again

 

[alldodge]

Don't stay gone so long, stick around were not that bad to listen to, helps if we have beer

 

[Scott Danforth]

305 heads are $25 at your local u-pull it salvage yards, and about $80 to have them refurbished. brand new heads from GM are about $250 each

get new manifolds. using used manifolds is like using soiled underwear.