outboard to inboard conversion

[taqwache]

ok here is a good one. i got a 78 V20 steplift that has been in the family since 1979. it came from the factory with twin 75hp mercs. after 10 years or so of saltwater use, those went bad and my dad repowered with a single 175 mariner. now after another 10 years or so of saltwater use, it has also gone bad along with the transom. since then the boat has been sitting for 5 plus years in his back yard. now me and my dad plan on restoring it. i found this site and noticed that these boats also came with inboard/outboards which is what i want to use. since the whole transom needs to be replaced anyways, how hard would it be to just mod it for and inboard/outboard? i was planing on useing a modified 400hp 6.0L gen3 chevy with a mercrusier alpha one. i know it will be difficult but that does not matter. i am very mechanicly inclined but i dont have to much boat experience. although i can learn very quickly. i can build a motor for almost free but i will have to buy all the other marine parts. what do yall think? what else is different from the two styles of boats (OB and IB/OB) that will be a challange?

[frayed_knot]

You won't get much support with that mod I'm afraid. Most everybody does the opposite. I'm sure it's do-able though, but will require a "boat load" ( ;D) of structural mods to be able to bolt an engine into the hull. Your choice of engine and drive is curious to me. Why go with that engine? An Alpha 1 of any generation is not a good choice for anything above 300 hp. You would be much better off with a Bravo drive. I would spend the $$ on a good OB after restoring the transom.

[frayed_knot]

You won't get much support with that mod I'm afraid. Most everybody does the opposite. I'm sure it's do-able though, but will require a "boat load" ( ;D) of structural mods to be able to bolt an engine into the hull. Your choice of engine and drive is curious to me. Why go with that engine? An Alpha 1 of any generation is not a good choice for anything above 300 hp. You would be much better off with a Bravo drive. I would spend the $$ on a good OB after restoring the transom.

[spareparts]

I'd have to agree with frayed and I'm a Mercruser Tech by trade. Thats way too much hp for this hull, it would go to waste. The bravo would be a better choice for that engine as well, you could git an Alpha to hold it if you wern't dogging it too hard. Best solution if you want to have an I/O. Trade your boat to some one with an I/o boat that wants to convert to an outboard. Espcially in salt water, your just asking for more work. If you really want an I/O, try a Volvo 5.7 320 HP with the XDP composite drive. Thats a slick package and salt won't touch it( I service a pair XDP's behind twin 8.1's in a 34 Cruiser). If you allready have the engine, try finding a used 22 Velocity(Regal sold them for a while), thats a boat that will put that motor to good use

[spareparts]

I'd have to agree with frayed and I'm a Mercruser Tech by trade. Thats way too much hp for this hull, it would go to waste. The bravo would be a better choice for that engine as well, you could git an Alpha to hold it if you wern't dogging it too hard. Best solution if you want to have an I/O. Trade your boat to some one with an I/o boat that wants to convert to an outboard. Espcially in salt water, your just asking for more work. If you really want an I/O, try a Volvo 5.7 320 HP with the XDP composite drive. Thats a slick package and salt won't touch it( I service a pair XDP's behind twin 8.1's in a 34 Cruiser). If you allready have the engine, try finding a used 22 Velocity(Regal sold them for a while), thats a boat that will put that motor to good use

[willy]

If you are going to do the transom restore, I would suggest you close it in completely and add a full bracket to the back and add a single 150 etec or similar motor. Nothing bigger and you will have a mid forties performer that will be less maintenance intensive and generally more reliable across the board. Actually if you add a 115 - 150 to a bracket on the back of that boat you will have the best performance package you can have, it will be very quiet behind that full transom and you will increase the sea worthiness of your V at the same time. JMHO

[willy]

If you are going to do the transom restore, I would suggest you close it in completely and add a full bracket to the back and add a single 150 etec or similar motor. Nothing bigger and you will have a mid forties performer that will be less maintenance intensive and generally more reliable across the board. Actually if you add a 115 - 150 to a bracket on the back of that boat you will have the best performance package you can have, it will be very quiet behind that full transom and you will increase the sea worthiness of your V at the same time. JMHO

[msbhammer]

Go Bracket son. ;D ;) and of course...post Pics. ;)

[msbhammer]

Go Bracket son. ;D ;) and of course...post Pics. ;)

[reelapeelin]

OK taq ... ya stated what ya wanna do and everybody's tryin' to talk ya outta it ... fact is, you can do most anything your wallet and skills can cover w/these hulls ... if I were doin' what yer talkin' about, I'd take the floor deck up and beef-up the stringers to handle the weight/power of the motor you want ...while yer that far into it, take the cap off and replace the notched transom w/a full one ... keep weight in mind, but put it all back STRONG ... post some pix here thru the modification ... I'd like to see it happen ... oh yeah...I think the '78 had a small gas tank (42?) ... be a good idea to add more fuel capacity while yer at it ;) ...

[reelapeelin]

OK taq ... ya stated what ya wanna do and everybody's tryin' to talk ya outta it ... fact is, you can do most anything your wallet and skills can cover w/these hulls ... if I were doin' what yer talkin' about, I'd take the floor deck up and beef-up the stringers to handle the weight/power of the motor you want ...while yer that far into it, take the cap off and replace the notched transom w/a full one ... keep weight in mind, but put it all back STRONG ... post some pix here thru the modification ... I'd like to see it happen ... oh yeah...I think the '78 had a small gas tank (42?) ... be a good idea to add more fuel capacity while yer at it ;) ...

[tsubaki]

Welcome to the site.
I'm with them about bracket. Bracket and twin 90's would be nice but at the very least go bracket.
POST SOME PICTURES!! ;D

[tsubaki]

Welcome to the site.
I'm with them about bracket. Bracket and twin 90's would be nice but at the very least go bracket.
POST SOME PICTURES!! ;D

[2ndchance]

BRACKET<BRACKET<BRACKET!!!!!!!!!
;D ;D ;D
http://i162.photobucket.com/albums/t270/2ndchance_2007/Wellcraft2207094.jpg

[2ndchance]

BRACKET<BRACKET<BRACKET!!!!!!!!!
;D ;D ;D
http://i162.photobucket.com/albums/t270/2ndchance_2007/Wellcraft2207094.jpg

[macojoe]

I converted from a I/O and its the best thing I have ever done!!

Go Bracket Young man and never look back!!

[macojoe]

I converted from a I/O and its the best thing I have ever done!!

Go Bracket Young man and never look back!!

[taqwache]

i didnt think i would get much support for this idea but that is ok. a bracket with a single OB is an easier mod and makes more sence if you want a good fishing boat but i am looking for something different. first off, i what to use this type of motor because i mod these for a living and i have enough parts laying around to build several engines intake to oil pan if i wanted to. if i were to go with a FI 2 or 4 stroke OB and later have problems with it, i would not know much about fixing it plus i dont have any hookups were i could get parts from for cheap. also, although this boat will mainly be used for fishing i plan on doing other stuff as well. like going several miles off shore to fish, doing long hual cruises from like houston to brownsville down the intercoastal camping on unknown islands along the way, and of coarse there is the water sking which i love to do. i just feel like an inboard/outboard would be better for me for stuff like this. plus when stuff breaks i could fix it easier. and then there is just the cool factor of having the only V20 with a 400hp LSX (gen3 chevy) motor that i probably will never be able to run wide open without killing my self. on the alpha or bravo deal, i just figured it would be easier and cheaper to get ahold of an alpha sterndrive then a bravo since there is thousands of them out there. that choice will have to be made up later since the main thing i have to think about is how much trouble this is really going to be.

[taqwache]

i didnt think i would get much support for this idea but that is ok. a bracket with a single OB is an easier mod and makes more sence if you want a good fishing boat but i am looking for something different. first off, i what to use this type of motor because i mod these for a living and i have enough parts laying around to build several engines intake to oil pan if i wanted to. if i were to go with a FI 2 or 4 stroke OB and later have problems with it, i would not know much about fixing it plus i dont have any hookups were i could get parts from for cheap. also, although this boat will mainly be used for fishing i plan on doing other stuff as well. like going several miles off shore to fish, doing long hual cruises from like houston to brownsville down the intercoastal camping on unknown islands along the way, and of coarse there is the water sking which i love to do. i just feel like an inboard/outboard would be better for me for stuff like this. plus when stuff breaks i could fix it easier. and then there is just the cool factor of having the only V20 with a 400hp LSX (gen3 chevy) motor that i probably will never be able to run wide open without killing my self. on the alpha or bravo deal, i just figured it would be easier and cheaper to get ahold of an alpha sterndrive then a bravo since there is thousands of them out there. that choice will have to be made up later since the main thing i have to think about is how much trouble this is really going to be.

[macojoe]

Well it looks like you have made up your mind!!

First thing is that you are going to have to beef up them rear stringers to take the load!

Next I think you are also going to have to widen the engin box, cause its going to be tight!!

Look at this thread, Cliff just repaired his rear stringers and reinstalled a motor

http://www.wellcraftv20.com/cgi-bin/yabb/YaBB.cgi?board=Repairs;action=display;num=11778521 67;start=0


When you get started take lots of pictures, and start a new thread so we can follow along and help were ever we can!!

Good Luck!

[macojoe]

Well it looks like you have made up your mind!!

First thing is that you are going to have to beef up them rear stringers to take the load!

Next I think you are also going to have to widen the engin box, cause its going to be tight!!

Look at this thread, Cliff just repaired his rear stringers and reinstalled a motor

http://www.wellcraftv20.com/cgi-bin/yabb/YaBB.cgi?board=Repairs;action=display;num=11778521 67;start=0


When you get started take lots of pictures, and start a new thread so we can follow along and help were ever we can!!

Good Luck!

[2ndchance]

Good luck and keep us posted with lots of pics or we'll send Hammer after you with his night stick ;D ;D ;D ;D

[2ndchance]

Good luck and keep us posted with lots of pics or we'll send Hammer after you with his night stick ;D ;D ;D ;D

[spareparts]

just use one of the smaller LS engines ( they made a 4.3 l V8 didn't they?), it wont over power your boat and will probably get a little better milage. Your problems are going to be in the EFI programming and in the accesories. Crusader has been marinizing the LS series engines so you can use their manifolds and brackets(expensive). Your going to have to use a speed density injection set up as the MAF style doesn't last long on the water(especially salt). My experiance with reprogrammed ECMs( from some very reputable supliers) has been bad, so bad that we went back to stock ecms, they only person I'll take a reprogrammed ecm from is Dennis Performance ( LIttle Washington, NC), he used to build most of the winning offshore motors before retiring( he built the engines in "Ohio Steel" and developed most of the blower setups that Merc racing uses). He wont have an ecm reworked unless he's got the engine on the dyno. If you have a complete repragrammable ecm( fatstuff, etc) you can probably rework it as you ride with your laptop, but be warned, feedback loops from the o2 sensors give a lot of problems due to the water mixing with the exhaust. You can buy a brand new ALphs drive from SDI.com for $1000-$1300 with a three year warranty. Better yet, give me that 6.0 for my 72 Stepside, and I'll scrounge you up a stock 5.0L carb ;D

[spareparts]

just use one of the smaller LS engines ( they made a 4.3 l V8 didn't they?), it wont over power your boat and will probably get a little better milage. Your problems are going to be in the EFI programming and in the accesories. Crusader has been marinizing the LS series engines so you can use their manifolds and brackets(expensive). Your going to have to use a speed density injection set up as the MAF style doesn't last long on the water(especially salt). My experiance with reprogrammed ECMs( from some very reputable supliers) has been bad, so bad that we went back to stock ecms, they only person I'll take a reprogrammed ecm from is Dennis Performance ( LIttle Washington, NC), he used to build most of the winning offshore motors before retiring( he built the engines in "Ohio Steel" and developed most of the blower setups that Merc racing uses). He wont have an ecm reworked unless he's got the engine on the dyno. If you have a complete repragrammable ecm( fatstuff, etc) you can probably rework it as you ride with your laptop, but be warned, feedback loops from the o2 sensors give a lot of problems due to the water mixing with the exhaust. You can buy a brand new ALphs drive from SDI.com for $1000-$1300 with a three year warranty. Better yet, give me that 6.0 for my 72 Stepside, and I'll scrounge you up a stock 5.0L carb ;D

[randlemanboater]

just use one of the smaller LS engines ( they made a 4.3 l V8 didn't they?), it wont over power your boat and will probably get a little better milage. Your problems are going to be in the EFI programming and in the accesories. Crusader has been marinizing the LS series engines so you can use their manifolds and brackets(expensive). Your going to have to use a speed density injection set up as the MAF style doesn't last long on the water(especially salt). My experiance with reprogrammed ECMs( from some very reputable supliers) has been bad, so bad that we went back to stock ecms, they only person I'll take a reprogrammed ecm from is Dennis Performance ( LIttle Washington, NC), he used to build most of the winning offshore motors before retiring( he built the engines in "Ohio Steel" and developed most of the blower setups that Merc racing uses). He wont have an ecm reworked unless he's got the engine on the dyno. If you have a complete repragrammable ecm( fatstuff, etc) you can probably rework it as you ride with your laptop, but be warned, feedback loops from the o2 sensors give a lot of problems due to the water mixing with the exhaust.


:o :o :o :o :o :o :o

Thats what I was thinking.

[randlemanboater]

just use one of the smaller LS engines ( they made a 4.3 l V8 didn't they?), it wont over power your boat and will probably get a little better milage. Your problems are going to be in the EFI programming and in the accesories. Crusader has been marinizing the LS series engines so you can use their manifolds and brackets(expensive). Your going to have to use a speed density injection set up as the MAF style doesn't last long on the water(especially salt). My experiance with reprogrammed ECMs( from some very reputable supliers) has been bad, so bad that we went back to stock ecms, they only person I'll take a reprogrammed ecm from is Dennis Performance ( LIttle Washington, NC), he used to build most of the winning offshore motors before retiring( he built the engines in "Ohio Steel" and developed most of the blower setups that Merc racing uses). He wont have an ecm reworked unless he's got the engine on the dyno. If you have a complete repragrammable ecm( fatstuff, etc) you can probably rework it as you ride with your laptop, but be warned, feedback loops from the o2 sensors give a lot of problems due to the water mixing with the exhaust.


:o :o :o :o :o :o :o

Thats what I was thinking.

[taqwache]

thanks for the info guys. i was thinking about useing the crusader marine parts also since there one of the few people useing these in boats already. i also plan on useing a fresh water cooling system since it seems like the best thing to do for salt water. on the programming, i got that covered since that is also what i do at work. my main conserns right now is modding the transom and beefing up them rear stingers like macojoe was talking about. then i still have to convince my dad that a little bit less cabin space is acually a good thing, hehehe. dont worry, i will take tons of pics but i will not be able to start on it for a while. right now i have to rebuild the trailer so i can move it from my dads house in corpus christi to mine in houston. by then my mind will be made up and i will start working on it. of coarse i still might change my mind later on down the road and go with a big 200hp O/B or something but we will see.

[taqwache]

thanks for the info guys. i was thinking about useing the crusader marine parts also since there one of the few people useing these in boats already. i also plan on useing a fresh water cooling system since it seems like the best thing to do for salt water. on the programming, i got that covered since that is also what i do at work. my main conserns right now is modding the transom and beefing up them rear stingers like macojoe was talking about. then i still have to convince my dad that a little bit less cabin space is acually a good thing, hehehe. dont worry, i will take tons of pics but i will not be able to start on it for a while. right now i have to rebuild the trailer so i can move it from my dads house in corpus christi to mine in houston. by then my mind will be made up and i will start working on it. of coarse i still might change my mind later on down the road and go with a big 200hp O/B or something but we will see.

[axespino]

Where are you located? *I have a 74 model V20 that I picked for the sliding hatch. *It had the straight 6 cylinder motor with the mercruiser outdrive. *The outdrive is still there but the motor is missing. *I have a spare motor and outdrive sitting in the barn. *The spare outdrive was rebuilt and probably has less than 50 hrs. *I am never going to use these and if you are interested maybe we could work out some sort of swap. *Look in the general section and you will see some of the pics. *The floor was partially cut out and never repaired. I am located in Palacios, Texas.

[axespino]

Where are you located? *I have a 74 model V20 that I picked for the sliding hatch. *It had the straight 6 cylinder motor with the mercruiser outdrive. *The outdrive is still there but the motor is missing. *I have a spare motor and outdrive sitting in the barn. *The spare outdrive was rebuilt and probably has less than 50 hrs. *I am never going to use these and if you are interested maybe we could work out some sort of swap. *Look in the general section and you will see some of the pics. *The floor was partially cut out and never repaired. I am located in Palacios, Texas.

[spareparts]

if you feel like you have to play with efi, pick up a 2.4 bridgeport or a 2.5 performance motor, there are lots of stuff on them you can play with. Just bolt it on the back, fix the 175 power head back stock and use it as a backup power head

[spareparts]

if you feel like you have to play with efi, pick up a 2.4 bridgeport or a 2.5 performance motor, there are lots of stuff on them you can play with. Just bolt it on the back, fix the 175 power head back stock and use it as a backup power head

[frayed_knot]

I, for one, would love to see you do it. It would be unique for sure. Again though, your engine choice, I understand what you are saying by having the parts laying about, but there is a point of diminished returns on this hull. In other words, 400 hp would be way overkill for it, and the only thing you will likely get by pushing that much hp is a squirlly boat. Hell, if ya lived closer, I'd help ya out, and I'm a Ford guy ;) Go fer it.

[frayed_knot]

I, for one, would love to see you do it. It would be unique for sure. Again though, your engine choice, I understand what you are saying by having the parts laying about, but there is a point of diminished returns on this hull. In other words, 400 hp would be way overkill for it, and the only thing you will likely get by pushing that much hp is a squirlly boat. Hell, if ya lived closer, I'd help ya out, and I'm a Ford guy ;) Go fer it.

[reelapeelin]

Fire when ready taq...we'll be here ;) ...

[reelapeelin]

Fire when ready taq...we'll be here ;) ...