View Full Version : motor swap

09-13-2013, 12:59 PM
In my 98 outback I have a PCM 350efi and I wiped a rod bearing this past weekend it just so happens that I have a brand new 383 Chevy crate motor in the garage and I was thinking about putting it in the boat. I know I have to reverse the rotation but I was just wondering if anyone on here had ever done anything like this, if its a good idea anything special I need to look for. I was thinking about it just because of the more torque I could get out of the boat especially when loaded down it should be able to come out of the hole much better. Let me know what you guys think. Thanks

09-13-2013, 01:20 PM
Well, it's still a small block so I wouldn't expect it to be all that hard to make the switch. You would need a new prop. I'm not sure about the shaft. I imagine you also have to replace it with the rotation and prop change though. Starting to get expensive.

09-13-2013, 02:03 PM
I've been told the internals are very different - especially in the valve train: springs, camshaft, lifters. Could include the bearings and rings too since the marine environment can be a bit more harsh than the road.

I don't know about you guys, but I don't floor my truck 30 times a day or run at 4,000rpm for any great length of time. Well, at least not since I was 17.

09-13-2013, 03:00 PM
What I was thing was keeping the top end the same heads can intake, just swapping the bottom end so i wouldn't be changing everything and new prop would be ordered

beat taco
09-13-2013, 04:02 PM
On bottom ends I'm pretty sure it's just brass freeze plugs. I would also want my oil pick up braised on.

09-13-2013, 04:37 PM
Have you checked the rotation. If your eng is reverse rotation the bearings and cam will need to be changed.
Gm made a change in the crankshaft in the late 80's from a two piece to a single piece rear main seal. The flywheel/flexplates changed aswell.

The only difference in the two is the crankshaft(350 is internal balance 400 is external) and wrist pin height on the pistons.
With the extra displacement your injection may need to be remapped.

09-13-2013, 05:26 PM
I was wondering about the injection hopefully it will all work itself out because I'm thinking about doing it this coming week and brass freeze will be installed

09-13-2013, 05:31 PM
it just so happens that I have a brand new 383 Chevy crate motor in the garage

This is a problem I wish I had more often :)

09-13-2013, 06:14 PM
Yeah it kind of fell in my lap now just hoping that everything will work out

09-13-2013, 10:53 PM
I have no dought it will run.
You might want to keep an eye on the plugs to make sure it isn't running lean.

Witch cylinder did you lose the rod bearing on. I ask only because a weak injector could have caused that cylinder to go lean letting start detonating(spark knock)destroying the that particular rod bearing.

09-13-2013, 11:25 PM
Haven't pulled it down yet but I had an oil come off on the water one evening ended up being a long one but I fixed it and it ran ok then it started knocking....decided to keep running because I knew I had another motor didn't want to ruin the whole weekend but it finally gave up, but I will definitely check out the injectors while I have it a part clean them all up and make sure they all flow freely

09-16-2013, 10:55 AM
Transmission? Correct me if I'm wrong but if you have a reverse rotation, your tranny is going to last long.

09-16-2013, 04:42 PM
I'm going to reverse the rotation of the 383

09-16-2013, 09:31 PM
I was looking at mine today 2000 indmar assult 325mpi is counter clock wise looking at eng from front(same as my truck).

the extra displacement and longer stroke should do nicely.

09-16-2013, 10:38 PM
I'm going to reverse the rotation of the 383

Gotcha! Sounds fun.