Swapping a 3.0 for a 4.3

I have a 1991 Glastron runabout with the original 3.0L I-4. I would like to swap that slugish 4 with the 4.3L V-6. I don't know how much work it would be. Any advice on the swap would be greatly appreciated.

Re: Swapping a 3.0 for a 4.3

Major PITA to do.<br />Just about everything you have now is wrong, from gear ratio in outdrive on.<br />Easiest way is find a junk donor boat with a 4.3 and swap it all out.<br />Not cost effective at all to do this conversion.<br />Bust course of action is to sell present boat and buy one with the power you want.

Re: Swapping a 3.0 for a 4.3

I have to agree with Bomar. I just converted my 4.3 one part manifolds to two part. Cost: Y-pipe $459, manifolds, risers, turndown elbos and other parts were an additional $1500. Labor was a pain in the butt and I didn't have to buy an outdrive or deal with the differences in motor mounts.

Re: Swapping a 3.0 for a 4.3

I can tell that this project is not highly recommended. Now does anyone have any suggestions on getting more power out of the 4 banger. I was thinking of having the heads ported. Please help.

Re: Swapping a 3.0 for a 4.3

I have also thought about a complete build up of the motor. Including boring the cyl. However I am not sure about the availbility of parts.

Re: Swapping a 3.0 for a 4.3

Have you thought about pulling the whole package and sell it as a ready-to-go solution to someone in need?<br /><br />After that you could hunt a bargain on a new engine/drive and get the best of all..<br /><br />Any performance job (turbo, cams etc.) will cost more than it will add to the boats value, give you one or two headaces and keep you off the water for some time.

Re: Swapping a 3.0 for a 4.3

NPClark;<br /><br />Tell me what you want from this boat interms of additional performance and how you use the boat. I may have some suggestions

Re: Swapping a 3.0 for a 4.3

If you want just a little more ump there are couple of easy things to do...porting the head is one.....in fact I ported mine just like some of the small block chevy's I have raced seems like gained couple of hundren rpm and I swapped the rocker arms for some 1.6 s I had laying around that got another hundren.....but then had to reprop to get it back down in recommended range....after all said and done may have got 5 mph oh and did shave .050 off head while had it off still not an 4.3 but about the most you can do with what you have.<br />I also had to carefully tune engine after these mods, alittle more jet in carb etc. basic hot rod stuff. just run short time read plugs adjust new plugs go again........hey I love to tinker

Re: Swapping a 3.0 for a 4.3

nautiJohn,<br />I would like to get more out of the hole. with out loosing my top end. I mainly use the boat for skiing. I love to ski with someone, but the boat has a had time getting two up. Thanks again.

Re: Swapping a 3.0 for a 4.3

npclark;<br /><br />If you would have said that you used the boat for wake boarding I would have to tell you that trim tabs may not be what you want - they cut the wke in half.<br /><br />Check into Smart Tabs (should be less than $170.00). Search this site. The problem you have in getting this boat on plane is that the balance is not good for what you want. Ski boats put the engine in the center of the boat (eats up a lot of room) to keep it balance and the boats accellerate flat and smooth. Trim tabs will accomplish the same thing - the tabs will keep the stern from dropping and the accelleration will be much more linier. <br /><br />This will give you much more performance than an engine swap for what you want. Keep in mind that most of the HP of an engine is developed in the mid to high RPM range, and by then you should be on plane. You are currently digging a hole to climb out of, with the tabs you won't dig the hole, therefore the HP will translate into speed.<br /><br />Don't get fooled into a hydrofoil as they will not give you what is necessary for what you want to use the boat for. You need as much variable surface area as possible - like flaps on an airplane wing.

Re: Swapping a 3.0 for a 4.3

Are those rocker arms stock generic chevy parts? thanks

Re: Swapping a 3.0 for a 4.3

If you have a question, start a new thread of your own and ask it. This thread is from 2004.
You must have missed that big red bar.

Re: Swapping a 3.0 for a 4.3

Sorry, thanks for the reminder