TOPIC: difference between buick 350 and marine buick 350

Please help save what hair I have left. lol. Need to know the difference between marine buick 350 and standard buick 350. Have cracked block in my 1966 Evirude which is told has a buick 350. bought a buick 350 from a jeep pickup for the block. I know the heads are different but not sure what else needs changed. When turning engines over they both turn clockwise and the dist. also turns clockwise. How can I tell if they are the same rotation. Please help

Should be the same, BUT, use the old heads, marine gaskets, and the camshaft, as duration set up for lower RPM use in a boat. And all the Marine rated bolt ons..thats any fuel pump, carb, ALT/Gen, and starter. Any fuel or spark related.

you should be able to remove everything from the old block and use it on the replacement block. While the heads are off it may be a good idea to make sure you have the hardened valve guides for the unleaded fuels unless that has already been done. Is it a raw water cooled V-8 or closed system? I had twin 283's in my Owens and I went through both sets of heads to be sure I did not have any problems especially because my motors were raw water cooled.
it doesn't take much for vapor or water to get in if a problem develops.

while you can get to them,change the freeze plugs in the block to brass ones. if it is a flat tappet cam,be sure the lifters go back to the same lobe they were on. otherwise,you could ruin the cam.

good point.

Thanks for the info but I ran into a problem. Come to find out that the friend that I got the boat from thought the engine was a 350 buick but its actually a 300 buick. I've been on the net all day long trying to find water exhaust manifolds for the 350 but no luck. Thank you again for your time.

According to this, the 300 and 350 use the same block and heads. All externals should bolt up. books.google.com/books?id=0gaA5cQXYPkC&pg=PA14&lpg=PA14&dq=300+cid+Buick+v-8&source=bl&ots=suhrIFTzfm&sig=jMxd-Igap0C6WxfhKllMmwvCqGA&hl=en&ei=IXWiTf-mI5PrgQeAwcDaBQ&sa=X&oi=book_result&ct=result&resnum=2&ved=0CCMQ6AEwAQ#v=onepage&q=300%20cid%20Buick%20v-8&f=false

if you are going to use heads from a 350 you should be able to get a set of glm or osco manifolds and risers no problem. I used glms on my vintage 283's

Whoops. ya got me there, I forgot need to go brass, and yep on any cam change!

On exhaust, also replace, don't use the old, if in salt especially. I have a 77 Bayliner, 350 GM, did new mans not long ago, upgraded the old Volvo stuff to new GLM, complete, and the best deal was off Fred Warner, on Ebay. Cheap fast, can answer any question, highly recommended! Link
shop.ebay.com/fredwarner1/m.html?_nkw=&_armrs=1&_from=&_ipg=25

I could be wroung But dont marine Motors run Steel Cranks and 4 bolt mains due to the extra stress on the motors ?? When I worked at a GM dealer ship a guy wanted us to put a new motor in his Jet Boat . We had to order a marine short block 454 . Not cheap . Asked the parts guy why more cash and he said because of the better crank and 4 bolts .

I don't think the Buick 350 was used in production marine applications so marine exhaust manifolds would have to be fabricated. Could be wrong. 225 Buick V6 was pretty common and was pretty much a 300 with 2 cylinders removed. OMC did use the 225 V6 but surprised to hear of a 300 V8 in one. Cylinder heads were very different between 300 and 350. 300 had evenly spaced exhaust ports similar to small block Ford and 350 had a paired center set similar to small block Chevy...not the same design, just similar spacing style.