[andysperformance]

With money being tight I may be having to hold onto my boat for another year and wait another year to move up, so im thinking about at least swapping to a SBC if it isnt gonna break the bank too much if i can find used parts..

First what parts can i use off the 4.3? Is the Bell, and all front accessories and mounts the same? I know for sure i will need a longblock, intake and exaust manifolds, and distributor ( the carb i have is the same listed as the ones that come on the 350's so i believe i can just rejet) If anyone has done this swap before or have or know someone who has a 350 lying around for sale, (can need freshening) let me know..

Also I know the drive ratio is different, can i get away with the V6 drive and just reprop? if not, what is the ratio change just in the upper or lower unit, and can i just swap out that half? since its cheaper than a whole drive. Thanks!

 

[obnoxus]

Intake /exhaust/ distributor,,, and you should just be able to reprop.

Simple swap,,,, mounts will even be the same

 

[wtfo]

With money being tight I may be having to hold onto my boat for another year and wait another year to move up, so im thinking about at least swapping to a SBC if it isnt gonna break the bank too much if i can find used parts..

"I would probably only do it if you're going to keep the boat because you like it and want more out of it. I really like the one I had so I swapped a v-6 for a stroker motor and am really pleased with it. No question though that I've put way more into it than i could ever get out of it. If you're going to try and sell yours and step up to bigger and more power, it probably makes sense to just run it the way it is and put the money you would spend on it toward your next boat. As the market continues to be uncertain, used boats - especially gas guzzling performance boats, are veyr likely going to get to giveaway prices compared to values of a year or so ago - especially the ones that are a little older and not the hottest, etc... You can probably pick up a heck of a nice set-up that won't ned a ton of work for very little. depending on how fancy you want and what you're willing to do to work on a little bit of a project, you might even do it for not a lot less than you'll wind up spending on your engine swap (if you do the swap right).

"First what parts can i use off the 4.3? Is the Bell, and all front accessories and mounts the same?"

Yes on bellhouseing and front accessories as long as you get the same era motor. Mounts will have to move forward aproximately 4 inches - make sure you have room to move everything 5" forward and take note of whether or not you'll have to add or rebuild the support that the lower mount bolts to.

"I know for sure i will need a longblock, intake and exaust manifolds, and distributor ( the carb i have is the same listed as the ones that come on the 350's so i believe i can just rejet) If anyone has done this swap before or have or know someone who has a 350 lying around for sale, (can need freshening) let me know.. "

Do a search or two on here, there's been a lot of discussion on this topic. In terms of sticking with a budget, you're probably better off buying a fresh longblock with the tin and then adding a decent intake and carb. I'm pretty sure that if you have a merc thunderbolt iv, the distributor will work, just need different cap (and a couple more wires if you want to make use of the extra cylinders).

I have a nice v-6 laying around for sale, only 35 hours... vortec, edelbrock intake and carb..., new merc exhaust. OK, I know you want a smallblock and truth be told if I was really in a hurry to sell the one on the carport, I'd take adds out, etc...

"Also I know the drive ratio is different, can i get away with the V6 drive and just reprop?"

Sure, depending on what kind of set-up you're working with you're probably going to step up 6-8" in pitch if anything like mine. I've run with both 1.47 and the original 1.84 and the original gear ratio is faster and so what i run. I'm sure it does put more stress on the gears on take off though, won't be surprised if i lunch the outdrive at some point.

"if not, what is the ratio change just in the upper or lower unit, and can i just swap out that half?"

The ratio change is in the upper half...

"since its cheaper than a whole drive."

but remember that if you gernade the upper gears, the bits of metal will almost surely eat the lower too... I kinda of like the idea of buying a whole new drive if you feel the need to change gear ratios... that way if / when you frag it you have a spare. I would run what you have first, you'll probably be surprised if you have access to props in the right range.

Thanks!

Just my two cents...

 

[NstyLX]

Bill, I have a 350 and some other parts that may work for you. Shoot me a PM if you are interested!! Just figure out which direction you want to go!!


Dwayne

 

[hump]

I have a set of factory 5.7 Merc exhaust manifolds I will sell cheap. If your interested send me an email.

 

[wtfo]

OK, I could pony up...

I've got a factory 4-bbl manifold, and set of 1.94 / 1.50 heads (if you want to go the pre-vortec route), factory oil pan (painted bright red) and factory valve covers that I know of right off the top of my head... Probably have the other style exhaust elbows and connecting tubes... but the risers and manifolds off my donor engine were to rusted to be trusted...

Maybe some other odds and ends as well... I'm moving in a few weeks and am going to pitch a bunch of stuff anyhow.

Think I've also got a set of the split quick and quiet exhaust with the good mufflers, etc... but wouldn't just give that away...

If you get really serious, will see what else I can find during the moving purge.

 

[andysperformance]

Wow, thanks for all the help! I think I may just go ahead with it, and keep the 4.3 around to possibly reinstall in the boat when i go to sell it down the road .. This way if i do buy good stuff for the SBC I can always transfer it into another hull later.. I do like my boat, its just a little ruff riding being only a 21* hull, and a little cramped for the family.. I will probably still stay in the 24' and under class later so a SB should work great there also.. I will be sending email/pm's thanks again..

 

[texasbaja]

4.3-350

I did a swap in a BAJA 204 from the 4.3, purchased a 350 from victory marine and had no issues with parts. sold the 4.3 on EBAY and that paid for the work and part of the engine. sold the boat and still see it around. the drive ratio does spin the engine up quickly and changing the prop never got it correct.

 

[H8tank]

If anyone has done this swap before or have or know someone who has a 350 lying around for sale,

I have a newly rebuilt 350 with zero hours I pulled from my old GT 208, rebuilt the motor and lower unit OMC only to find the transom rotted. Decided to part it out instead of fix. $1500

Also have a brand new Mallory marine distrubitor/coil/wires to sell, and the OMC outdrive. New gears with 10 hrs, just serviced with all new seals/oil/impeller.

Let me know.

 

[Horse power]

Re: 4.3-350

the drive ratio does spin the engine up quickly and changing the prop never got it correct.

Thats how it worked for me when I did it. Could not find a prop big enough.

 

[andysperformance]

I have a newly rebuilt 350 with zero hours I pulled from my old GT 208, rebuilt the motor and lower unit OMC only to find the transom rotted. Decided to part it out instead of fix. $1500

Also have a brand new Mallory marine distrubitor/coil/wires to sell, and the OMC outdrive. New gears with 10 hrs, just serviced with all new seals/oil/impeller.

Let me know.

Thanks but I think I found what im looking for a little closer thanks to NSTYLX..
As for the outdrive, from what i am reading here it will work, just wont be optimum.. I will need to shop for that in the future, but what i have will work just to get in the water incase i run out of funds.. correct?
Thanks again..

 

[NstyLX]

Bill, what ign. system is in your boat? I also have a Thunderbolt(?) V8 dist. w/ like new cap, rotor, and wires. Also have the V8 module for it. The more I dig, the more I find!!

 

[andysperformance]

it currently has the thunderbolt ignition on it, but is what i read up above correct that I can reuse that distrib. if i just change the wheel and the cap? Also curious about the cam gear since its a roller cam.. Dont think the 4.3 is. and i just know from the mustangs when you change to a roller we had to change the cam gear.. But guess i will need a v8 module huh?

 

[NstyLX]

Need to check about the cam gear!! I agree that it prob. needs changed!?!?!? Talk to you soon!

 

[Mkos1980]

Nst, which V8 module?

 

[wtfo]

on prop's not working... surely you guys didn't look very hard if you didn't find props big enough???

If you're going from a 1.84 to a 1.47 that's a sizable difference, but there are a number of good options out there depending on the lift characteristics your that work best for your hull...

I went from somewhere around 230-240 horsepower to 400+ with the 383 and went from turning 23" laser2 4800 or so RPMs to turning a 28" hydromotive quad iv 5200 rpm, 27" mirage same sort of rpm (not as fast...). I've got a worked 27" spinelli 4 blade to try then several options including a labbed bravo 4-blade in 28"..., but I might not worry about it much since I've got a line on an alpha ss drive... Don't think it's going anywhere, just have been way to busy to get up wht the guy and work out a price, etc... that'll put me back to 1.47 gears...

Note that most of what I've read seems to indicate that for top end of 60+ props closer to pict 2x diameter are generally better performers. I had a 1.47 gear upper on my current out drive and the right pitch props to play with from the v-6 days, but the boat was just fasted with the 1.84 gear set-up so when I threw a ujoint to pieces (butt ugly sound and made the front of the upper look about as bad...), I dind't bother putting the 1.47 back together and am hapily running te 1.84... no problems pulling skiers, etc... and flys on the top end.

the mirage has too much cup / rake for my set up the way it is and so it porpoises a bit, the hydromotive was awesome but borrowed and probably a little too much diameter (assuming I can get more) so I haven't splurged and bought one yet. Also, I got really busy with other stuff (work insanity, buying a house), etc.. anmd then in the mean time, I think I've got an alpha ss to play with... Don;t think it's going anywhere, just haven;t had teh time to get up with the guy. That'll put me back to the 1.5 gear range so I'm kinda glad I kept the box of 21-26 inch props now...

stream of consciousness, but hopefully something useful in there. Guess te takeaway is that you can definately find props that'll work and in the rigtht picth range, but you have to look a little harder and be creative... you also have to realize tat some of the folklore on propping isn't always spot on when you get outside of the typical set-ups...

 

[wtfo]

OH, I just noticed your note about the 4.3... don';t be surprised if it is a roller cam... definately check before you assume not.... I want to say the original 88 model 4.3 in my boat was...