newb here, 1st question of many

[PowerAddict]

i picked up a 73 cobalt tri-hull with a 140hp mercruiser.

Now, the lower unit needs to be welded. However, I plan on putting in a SBC, will the lower unit for the 4cyl be stout enough for the added power? If not, where else should I look for a lower unit? Can anything be done to the one I have for strength?

thanks.

 

[ziggy]

Re: newb here, 1st question of many

most boats have a max eng. capacity. my 72 trihull is only rated for 165hp. sounds like yer going much bigger than that. do ya want to insure it?
that's also a lot of weight in the back. going from a 4 cyl. to a v8. how will that effect ya?
don't know if the drive will be up to the task or not. but at the very least it will need a gear ratio change to be compatible with a sbc......
sounds like you have much work ahead of you. as it sounds like yer gettin ready to change just about everything that is engine drive related to me......

 

[eriediver]

Re: newb here, 1st question of many

+1 What Ziggy said.
You're better off selling that & buying a boat with an 8cyl. if that's what you want.

 

[wire2]

Re: newb here, 1st question of many

Keep in mind, a small block V8 I/O assembly weighs ~ 1150 lbs.

 

[Haut Medoc]

Re: newb here, 1st question of many

Welcome to iboats.....
An old tri-hull ain't gonna handle 260 HP.....
I agree with the new boat idea if you want that much more speed.....
The hull is just not designed for it......​

 

[Limited-Time]

Re: newb here, 1st question of many

Speed on the water is expensive, and difficult to obtain with any reliability. If it just took dropping in a bigger engine with more HP any one cold do it.

 

[Haut Medoc]

Re: newb here, 1st question of many

Speed on the water is expensive, and difficult to obtain with any reliability. If it just took dropping in a bigger engine with more HP any one cold do it.

Could a caveman do it?......

 

[PowerAddict]

Re: newb here, 1st question of many

what about the tri hull makes it incapable of handling power? is it the drive system or body design?

I'm green, so I'm all ears.

 

[95yj]

Re: newb here, 1st question of many

Depends on which boat you have. The 16 footer only came stock with the 120, 140, 165 HP motors. The 18 footer came with a 140, 188 or 245 HP motor. The boat only weighs less than 2000 pounds including the motor, but you probably could get the V8 in there without exceeding the HP rating of the boat since it did have an option for one. You need to check the sticker on the boat.

You're still looking at spending a lot of money on a 35 year old boat. The boat will never be worth the money you spend wedging that motor into it.

 

[PowerAddict]

Re: newb here, 1st question of many

its the 16 footer.

Can I have a run-down of everything that would need to be changed or re-enforced to put a bigger engine into it (even if its a 6 cyl.)?

thanks everyone.

 

[PowerAddict]

Re: newb here, 1st question of many

TTT please.