guys i got an off the wall project i need some advice on, im takin an old 12-13 ft bass boat and puttin a straight 6 w/ an automatic tranny butted to an old lower unit off a mercury 60 horse....i know ittl work but i need to know what is the maximum angle i can tilt my engine and itll still run hard, and still get all the oil it needs without any modds? off roaders should know answer.....please help!!!?!?!?>@#$%

 

Around 10° high in the front. You'll get a lot of windage at that angle, and you'll probably go through rear main seals frequently. You're gonna need a BIG bass boat to stow a 300, and you're gonna have trouble finding/fabbing a marine exhaust manifold for it.

 

I say as long as you don't tip it for to long you should be all right if the engine is level when the boat is just sitting. If you ever looked at one in a truck the front of the engine sits up higher then the back. That's gonna be a lot of weight on the boat don't you think?

 

im lookin for a lil 250 chevrolet, but ive got a lil 144 for straight 6....its a tiny boat guys, i wanna get the kinda sleeper feel but on the water, i want ppl to look at it and say aw hell that aint fast....ya c what i mean.....im puttin a lotta foam to make up 4 the weight diff., i gotta cut out a lotta fiberglass to......yall gotta ne suggestions on how to hold the yoke inside the tranny at a stand still?....preciate the advice......keep it comin....lol

 

could there be any racin oil pump or ne thing else i could do to get more angle?

 

I havn't done much with boats for a few years, but I spent some time in R&D at Mercruiser when I got out of highschool. As much as I hate to say it you are wasting your time. I used to have a 12 foot jon boat that ran very well with a 20 or 30 hp outboard on it. The total weight with me, the motor and hull was probably around 500-600 lbs. Just putting a straight 6 in will nearly double that, plus you want to add an auto transmission that weighs probably at least 150 lbs with fluid and converter. The foam won't help with anything but keeping the boat off the bottom of the lake; it increases bouyancy but adds mass. Even if it will float and plane out the hull is not designed for that kind of weight. That's like putting 6 extra people in the back seat of the boat. Also, the 300 likes to spin about 3200 rpm at peak power. A v8 inboard engine is typically supposed to be propped to maintain 5000-5600 rpm depending on displacement. You want to further handicap the rpm potential of the prop by using an automatic transmission behind the engine reducing the output speed by 2.48 in first and 1.48 in second. In order to prop this thing to allow the use of the lower gears it would have to have so much pitch the engine couldn't spin it in high gear. If you reduced the pitch to work in high gear it would just cavitate in lower gears. There are stern drives available that were designed for diesel engines that would be more compatible with your rpm range, but they would suck up half the engine's power. There was a project like this in progress (using a 350 and TH350 trans) when I worked at Merc. If this worked you would see it all over the lake.

If you want to run a 300 in a boat you have a few options, although I don't think any of them are very good. The easiest was is to find all the parts from a 302/351 from the days when Mercruiser used Ford engines instead of Chevy's. I believe OMC also used Ford engines. This will get you the bellhousing you need to make this work. You can also use the flywheel from a Ford marine small block as long as it is neutral balance. After you get all the parts install them like a regular I/O drive. Put this together like it's a NA diesel because that's what a 300 runs like. This might turn out to run OK if you can keep it from spinning props.

 

true, but i want to find a small straight 6 like a 144, or so, straight so i wont have a problem with engine spin, im going to mount it like in a jet boat but with a slight more angle if at all possible, im also gunna try an run it like a circle track tranny (i think) if i remember right the run a transmission w/ out a torque converter, if i can i want everything solid linkage, everything except for the prop, so if i hit something it'll just spin the hub instead a tearing out all my gears....preciat the advice.....im still gunna keep at it and give em hell, maybe ill find a way and be famous someday....lol

 

How do you figure? The inlines have more low-end torque than the V-8s, but ANYTHING that's trying to turn MUST have a reaction force (torque); even a hamster wheel.

 

yes but the engine im after, all 6 cylinders fire straight up an down instead of at an angle...

 

They still have spin, believe me, I sheared the bolt off in my motor mount muddin, but I spose you won't be shiftin down through gears real hard then floorin it then jammin it in reverse, but steve83 is right torques torque and that 6 has plenty.

Redneck-Cowboy

 

yea more than likely im gunna just find an old jet drive and rig it up to a damn 302, seems a hell of a lot easier....lol

 

Yeah things never workout huh, but that 302 with headers and straight pipes will sound pretty good on the lake though, go for that airboat sound. But that engine is also just as heavy as the 6 so don't sink.

Redneck-Cowboy

 

i got the boyancy thing straightened out, tons a foam, plus ima cut out bout 200 pound of fiberglass to make up for engine weight, i wanna blow out windows when i pass them full throttle...that would be beautiful

 

Now you're talkin. But you probably won't find fish anywhere close to your boat.

Redneck-Cowboy

 

hell no this is a race boat not no bass boat ne more, a sleeper if u will....lol