Volvo 290 4cyl. To V8

I was wondering if I can take a Volvo 290 and convert it from the 4 cyl. to V8. I know it needs the lower unit regeared. But can I use the same transom plate and just change out the bell housing and exhaust.

My project is hopefully to Turn this 290 (with only 11 Hours on it) into a duoprop and put it behind my 5.0 liter that used have a 800 OMC. The Omc is now completely gone.
Maybe a little ambitious but trying to keep cost down and still repower to Duoprop

 

Yes.
It's not very difficult to switch the lower gear housings on the volvos. Everything from that point up is the same regardless of engine size. I'm not sure how cheap it will be - nothing in boating is - but you can probably find a good dp lower gearcase for $2K or less. The only thing you have to watch is the bearing crush between the intermediate and the lower housings. Shim to +/- 0.001", replace the O-rings, a little permatex and you're good as new.

I'm not familiar with the size of the hole OMC cut into the transom, but if it's smaller than the cutout necessary for the Volvo, you should be fine.
I see bell housings for 350's into volvo drives pop up once in a while (I think this is the same as the 305/5.0), which is probably your cheapest option. You may have to play with your engine mounts to get proper alignment. This too is just simple math with the help of factory specs.
-Tom

 

Am I just a bad reader or are you planing to use two 4cyl volvos to make 1 v8?

I know there has ben made a v8 hayabusa engine. Unless you can find a v8 crank with the same lenght betwen the cyl and stroke as the original I don't exspect it to be cheap since you would have to turn up to some tuning company that can make a specal one just for you.

 

Thanks Tauntom
I will have to have the hole filled in then recut. I was quoted $500 for this procedure. You answered my concerns. As long as I dont have to get a new Transom Plate I will be a "happy camper" . The Bell housings seem pretty easy to come by, but the "y " tube for the Exhaust dont seem to come up very often. But Im looking foward to this project.


To Answer StianM. The 290 come from a 4cyl and I want to put it on a V8 305.

 

I have no idea how this is suposed to work. clone parts from a volvo with a 305 block seam like a crazy idea to me.