advise needed on engine size for a V20

M

mgraniello

Member
What is the biggest mercruiser that can fit into engine compartment of a V20? I am looking to replace the 165 straight 6 with a V4 or V6 and I am not sure what I can do???
 
Welcome to the site mgraniello.


CTT has a 350 Chebby in his, and he is so darn good lookin.
 
I'm sure a few of our resident motorheads will be along shortly to help you out. I know we've got one or two members here w/ 350 c.i. power.....maybe that overly handsome man CTT....Lotsa guys here that know what they're talking about ;)and welcome to v20.com
 
Here is a pic of my old V20 engine

P3260096.jpg
 
165 motor is a dog!! I know I had one for a long time!!

I am sure the 350 is much better but its a lot of work!!

If I was you I would be converting to a OB, I and many others have done it and it is not hard at all!
as long as your transom is solid.

Then you can ad any motor you want to it, when ever you want to!
 
That sounds like a good idea how do you go about converting to an outboard? How does the boat handle with the outboard? Do you not have it sticking out for from the boat? is there a ploatform that I need to buy to do this?
 
did you convert yours to an outboard? do you have any pictures of it from the stern I can view? the more i think about it the more i like it. it can free up a lot of room in the back of the boat. i am just concerned about how the boat will handle with the extended motor
 
You can see all the repairs here, not as much detail as I had hoped, but I can answer a lot for you, I fixed the hole in a afternoon and the install of the bracket in 2 dfays cause I measured mesaured mesured till I thought it was right ;)

But you can be boating in a week if you have the time and all stuff there when you start.

http://www.wellcraftv20.com/gallery/view_album.php?set_albumName=album09


And my boat is forsale here with lots of pic's

http://www.wellcraftv20.com/cgi-bin..._sale;action=display;num=1187641051;start=0#0
 
There's a little bit to consider when going from the 165 to a V style engine. I'm not sure if the stringers are the same distance apart, gotta check that first. Also, depending on what engine you decide to go with, you will need a different upper gear box ratio on the outdrive. For instance, my 5.0L Mercruiser has a 1.5 gear ratio, I'm positive yours doesn't. The easiest thing to do there is to buy a new upper, sterndrive engineering has a great unit at a great price. They can also help you select the proper gear ratio. Of course, like has been mentioned already, you can go with an outboard on a bracket, a very popular modification. The only downside I see with that is buying the engine, but there are plenty of used ones for sale at decent prices. Good luck and keep us posted.
 
the 165 engines had a 1.84 ratio from the factory, some did come with the 1.65 ratio that was standard on the 5.0L engines. You may be able to make up some of the gear diffeence with prop, but sooner or later you'll want to change to a 1.50 HD gear set( especially if you repower with a strong 5.7). Most of the boats had the stringers in the right location, but they didn't have the pads installed for the motor mounts to sit on, not that hard of a job to install. You will also have to change the input shaft on the drive, the exhaust will have to be changed over to a Y pipe for a V engine configuration. Your 165 probably didn't have power steering, its a recomended option if your going to install a V8. What it boils down to, it would be best to find a complete 5.7 set up( engine, transom plate, drive) in a junk boat to install rather than piece meal one together. The easiest solution is to replace the 165 with a rebuilt longblock( ebasicpower.com has them), or if you want more power, find a 292 truck motor, it will fit in the same place, you will have to install a longer exhaust hose, and may have to raise the engine box a few inches, it would also be best to put a 4bbl carb on teh 292(thats what the 4bbl flange on your manifold is for, they used the same manifold for both engines).
 
Thank you for your reply! If I convert to an outboard motor configuration does the boat handle any differently? Is it much different from having the I/O installed. I would imagine with the I/O installation it would handle and ride better because it was designed for it. However, the boat would have so much more room with out the engine box! How much can I pick up a good used 200 hp outboard motor for?? If I was to have the conversion motor mount installation done by a proffessional, how much do you think it would cost?
 
Well it i easy to fix yourself if you are handy, if you go to a glass guy I bet he would want almost $1000 to fix the hole!

The bracket depending what company and style you go with will cost $800 to $1700

I got my bracket used from am near by mariner for $400 so you might want to call around to see if any one has a take off hanging around.
CK ebay and local ad's for brackets they can be had for short cash if you look around.

Motors are all over the place, all up to you what you want to spend? I have a 175 Evinrude that I got for $700 complete and runs great!

Boat handles great after conversion! Best thing I ever did!! You have better trim and cuddys ride so much better theuy are balanced more.

The only thing is that bracket boat don't like to go in reverse hard. They Idle while backing down great, but hit the gas and they just like to go stright back, no turns cause the wash is pushing against the boat.

I did my conversion for $400 Bracket $100 supplys + motor
 
I just replaced the 4.3 litre mercruiser in my 1991 V20 with another 4.3 litre mercruiser. The 5.0 litre mercruiser v8 would have fit without any modifications to stringers, etc. I do not know about a 350. The 4.3 does a very good job with my V20, with top end around 45 mph.
 
You must log in or register to reply here.
Back
Top