new engine

[Banditdog]

hello boys and girls, Well we had some excitement this moose season, some injuries, some damage and sunk my boat in a high silt glacier river. Water levels were way above flood stage for several weeks so couldn't attempt to recover the boat, finally the water went down and winter came on.
We took snowmachines and got to the boat, used chain saws to cut it out of the ice and by brute force and awkwardness managed to get it up. Started to pull it over the ice to try to take it home and the ice broke 13 inches thick, and down it went again.
We got it up onto the river bank high enough so that it won't damage the hull and left it till spring time when we can go in by boat and wash out about a ton of sand and float it downriver to the road.
So, engine is shot, 350 Chev direct drive to Hartzell pusher prop. Seat mount, prop cage and some motor mount damage.
Now the questions, more power would be good but I don't really want to go to a reduction drive, this is an old Panther boat and is really low in the transom so lighter would be better. I could go to a 454 but that's more weight, I could go to a Vortac V6 but that requires a reduction drive to get power so doesn't really save any weight.
If I could find an LS aluminum block engine that would be great but would require computer controls and perhaps the prop would not fit and the motor mounts might be different.
Or, I could find another old 350 truck engine and just put it back like it was.
What do you recommend???????

 

[John Fenner]

I would suggest a 400, there are quite a few posts in the search menu on how to blueprint a direct drive for optimum power and torque.

 

[BobBrack]

I love the LS platform but I would do some research on how the crank and thrust bearings hold up to the prop thrust. If the answer is they do good, then that is the direction I would go in. Then upgrade the cam and valve springs and let her eat!!! They weigh around 400 lbs and make a lot more power than the 350 which weighs at least 100 pounds more. As for the computer There are several out there. If you want to run a carb on it the computer will run you about 600 and if you want to go fuel injection the cost is double. Plus the added cost of the fuel system.

 

[SWAMPHUNTER45]

I agree with Fenner

SBC 383 or 400 would pop right on your rigging and offer a power upgrade without breaking the bank.

 

[Uhairball]

what happened to the moose?

 

[glades cat]

You may want to contact Waterthunder. He has developed a thrust block for the LS direct drive application. Apparently, that is a weakness of the LS engines without a gear box.
A small block 400 or a stroked 383 with aluminum heads can save you some weight.

 

[Slidin Gator]

hello boys and girls, Well we had some excitement this moose season, some injuries, some damage and sunk my boat in a high silt glacier river.

Dude, been there, not all the frozen stuff though. Burrr.

this is an old Panther boat and is really low in the transom so lighter would be better.

Iron/aluminum 350 vs. 6 Cyl Aviation vs. Geared aluminum LS are all in the same weight range and in order of power, complication and cost. For the same power level you had and less weight think 4 cylinder aviation.

A full iron 454 would be awesome if you wanted to sink it again this summer, add gear and sink sooner. 454, all the weight of a big block and mosta the power of a small block.

Don’t try a direct drive LS, they are gear motors.

You can put carb and simple spark on Aluminum LS engines running gear for reasonable price, stick with older Cathedral port heads. But you are gonna want clearance for 80" of prop.

 

[hdsadey]

Small intake ports, dual plane intake, short duration high lift cam, 500 CFM 2 barrel or 450 CFM 4 barrel. Trick to a stump pulling direct drive is manifold velocity. 400 small block with a 4 inch crank would work well. Even a 3.85 stroke would help. My 408 Windsor did amazing as a DD until the new boat got too heavy. Gearbox is the best route.

 

[John Fenner]

Small intake ports, dual plane intake, short duration high lift cam, 500 CFM 2 barrel or 450 CFM 4 barrel. Trick to a stump pulling direct drive is manifold velocity. 400 small block with a 4 inch crank would work well. Even a 3.85 stroke would help. My 408 Windsor did amazing as a DD until the new boat got too heavy. Gearbox is the best route.

I have been wanting to find an aluminum "Dart" or equivalent tall deck block with long stroke and stout internals, a roller cam from a 4.3, V8, heads and intake as well,, those baby lt1 engines ran good, imagine the torque built on this platform.

 

[SWAMPHUNTER45]

Fenner there were 2 GM little V8s that Mr. Branch would collect little trinkets from and cross them over to the Cadillac builds.

Since he is gone and the world appears to be going LS, I don’t suspect he would mind my sharing one of his secrets.

He was absolutely anal about setting up a mechanical distributor timing curve. I had spent a full day in the shop with him on one engine where we must have changed weights and springs 20 or more times.

He had a special little drawer with weights and springs pulled out of both the 4.3 and I think the 260 Olds aluminum V8 engines. They were shaped and weighted differently and were almost always exactly what he wanted.

I should have made notes as the weights had a number stamped on them. That curve in a Direct Drive is more important to the engines performance than most people think. Most people are either to lazy or don’t understand the process but if they spent the time experimenting they would find the best $ to power gain for the money.

 

[hdsadey]

WOW I have to admit that I knew nothing about the 4.3 V8 and had to look it up. Thought you were pulling my leg, was like a 4.3 cam is 4 lobes short lol. It sure would be interesting to see what kinda of numbers could be pulled out of a combination like that. If you could find all the components I'd do the machine work and put it on the dyno. Might be tough to pull it down low enough to get a proper power reading.

 

[Aeon]

How about some pics of what you did!!!!!!!

 

[John Fenner]

Well a boat I built in 1988/9, the owners son was an engine builder, went through many combinations, 400 block, reciprocating internals, 267 heads, 267 cam, 305 truck intake, 390 Holley carb tuned and jetted worked best, now his dyno was a 72 LXL 42 wood prop, it was quite a workhorse, fast forward to 2005 or so, that 400 was tired, rebuilt many times, out of spec, we got a TIO-520, I put 8.6:1 pistons in it, bolted the whirlwind stump puller, "un touched pitch settings" from the 400, had to take pitch out of the prop to get it to spin up, there are many varitives to building a torque monster.

 

[Banditdog]

what happened to the moose?

No moose this year, too many distractions with doctors and stuff, this is from the year before.

 

[Banditdog]

How about some pics of what you did!!!!!!!

This is my old boat before the wreck. This is the left front corner embedded in 20" ice, running light and top of prop cage visible. We used chain saws and cut it out of the ice. The log showing in pic 4 is what caused the crash. It runs out into the river about 45', it was just under the surface and it caught the chine on the hull and tracked us sideways right into the big log showing in pic 3. We got it lifted out of the ice and water and got it on top. We pulled it over the ice trying to get where I could get my tractor but it broke through the ice and sunk again. Too much weight of sand and ice. We had a better location this time so we pulled it up onto the bank where it should be safe until spring when I can go back in by boat and wash all the sand out and free float it back down river to the landing and bring it to town.
The engine is shot, the seat mount was crushed. The rudders, prop and hull are OK. I would like to find a used prop drive unit but if I can't I will get another SBC, get the structure all welded up and be ready to go.

 

[Deano]

Dammit, man. I got cold sitting here looking at those pictures. 🥶

 

[Slidin Gator]

Looks like the boat needs more than a new engine. In the meantime, order up a new 383 long block and tell them hurry up!