470 to 350 swap?

[Cut n' Jump]

I've seen 4 bangers get swapped for v8's before. I have a nice set of v-8 manifolds from an old Chris-Craft and will be buying an 19ft v-hull with a 470 merc in a few days. I don't need to hear 'it can't be done'. Just wondering what snags I will run into. Mostly I'm worried about the crank adapter since I'd use a 96-00 vortec 350. I hope a larger speed prop would keep the revs down.

 

[MooseHootie]

Re: 470 to 350 swap?

The 4 cylinder mounts in the front and the v6&v8 mounts on the side . Check your stringer location.

 

[airman]

Re: 470 to 350 swap?

Make sure the hole is wide enough. I am thinking of the same swap for my boat but he engine compartment is too narrow. I talked to another mechanic who did it to his boat and he was very pleased with the results. You should consider getting a new gear set for your leg, rather than just changing the prop.

 

[Cut n' Jump]

Re: 470 to 350 swap?

I realise new mounts must be made. Plenty of room for a 350. It's actually a very wide 17' boat. Will I need a new flywheel housing? It has a Chevrolet bolt pattern but will the starter bolt up? I'm considering thru-hull exhaust and a gas PEDAL. Would a throttle linkage and y-pipe be better? Don't know if the exhaust is smaller on a 470 than a standard v-8 mercruiser.I looked at the boat in the dark with a weak flashlight. Didn't see the weak rotted transom and the 3 new gallons of antifreeze in the storage. The starter bendix is fried and maybe the flywheel too. I figure if I have to pull the engine for a transom repair I may as well swap in a v-8 and get rid of the 470 problems before finding them. Only $400.00 in this money pit so I can make a return or even a profit on the outdrive,trailer and engine parts. I would be better off starting with a v-6 or v-8 boat but I enjoy fixing things up. I'm not very familiar with inboards so maybe someone who has done this swap can make me a list of parts. That way I can make a budget and see if its even feasible.

 

[Cut n' Jump]

Re: 470 to 350 swap?

What I really need to know is what parts between the bellhousing and gimbal bearing wont work. I'm pretty much decided on swapping a 350 in.

 

[Bondo]

Re: 470 to 350 swap?

From the Rear Engine mounts Back.........<br />You'll need to change Only the Gear Ratio(upper gears).....<br />And Maybe the Prop........

 

[Cut n' Jump]

Re: 470 to 350 swap?

So the bellhousing[referred to as flywheel cover in previous post] will work if I leave the lower cover off? The bellhousing appears to have the rear engine mounts. Will it need a new flywheel? If I use a pre-86 350 [with vortec heads of course ]will the crank adapter work? Sorry for all the ignorant questions, I just don't want to jump in this all ignorant

 

[Cut n' Jump]

Re: 470 to 350 swap?

What I need to know is if the bellhousing that bolts to the back of the 470 will bolt to a 350 Chevy with no problem. Pretty much decided on fixing it.