340 boat motor

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tigey

tigey

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i got a 340 out of a 73 boat .i want to put the 340 in a 70 dart but i need to change the cam so ive been told.what kind of cam should i go with .any other input on what other steps I should take will be very helpful thanks.tigey
 
First thang you better do is make sure that damn thing is set up to run CW.

Cam / cam drive

crank seal flutes

water pump

starter rotation

Check the distributor drive

Engine ID tags
 
+1 on everything 67Dart273 said, there are several good modern street cams out there but you would have to change the valve springs too.

Where in CO are you btw?
 
thanks for your input"67dart273"its clock wise .i will look into the other items you mentioned i .dont know what a crank seal flute is.MOPEkidD-3 iam about 20 west of aspen.thanks guys ill wil post pics soon
tigey
 
The stock intake is likely machined on an angle to help level the carb in a boat.
 
The heads will have valve rotators in place of the regular valve retainers. They limit the amount of lift you can add to the cam. Also I think the heads might be a 318 small port head as well, check the #'s.
 
What kind of boats came with 340s? That would be kinda cool.
 
A friend of mine has a house boat he redid from the early 70's it has two 340's in it
 
67Dart273 said:
First thang you better do is make sure that damn thing is set up to run CW.
Click to expand...

Actually you mean CCW in relation to the car, i.e. from the driver's seat. Only time you run into an opposite direction motor is with dual motor setups to counteract the side thrust. If boat was an original single motor, should not be a problem.
 
Old Correct Craft Barracudas run CCW. Single engine Ski boat. Like 67Dart273 said. Crank, cam, distributor, timing cover, water pump are different.

 
We used to rent a small warehouse to store/work on our cars before we built the one in our back yard. It was in an industrial park here. For a while there was a boat parked in the parking lot there, and we checked it out. It had a Mopar small block with a 4 bbl intake on it. We wondered if it was a 340 or what. But couldn't look at the numbers on the block to tell. It may have been one of these.

They are cool. I never heard about these before. And that was way before internet and google....
 
396 Signet said:
. Only time you run into an opposite direction motor is with dual motor setups to counteract the side thrust. If boat was an original single motor, should not be a problem.
Click to expand...

No not true. We are not a "big boat" area around here, Lake Pend Oreille and Lake Coeur d Alene, but I've seen a fair number of single engine installs that was reverse rotation. I THINK this tended to be "back in" the older inboard days as opposed to the later outdrives, but I don't see a great deal of boats, overall

I've had guys from the Seattle area tell me that reverse rotation engines are common in singles

to the OP when I was referring to flutes on the crank, it's the little serrations under the rear seal area. These are reversed in reverse rotation engines, and will probably cause seal leaks when run CW
 
If it's a runner great if your going to rebuild it have it sonic checked, boat motors can have bad erosion and a lot of rust in the water jackets, a lot depends on how much use and if it was properly winterized
 
tigey said:
thanks for your input"67dart273"its clock wise .i will look into the other items you mentioned i .dont know what a crank seal flute is.MOPEkidD-3 iam about 20 west of aspen.thanks guys ill wil post pics soon
tigey
Click to expand...

OK cool, I'm in Denver obviously (Englewood to be exact)... I actually have a new B&M flexplate that is offset-weighted for an external-balanced 340 that I have no use for, if you can confirm that yours is external-balanced (look at the crank damper) it might help you adapt it to a car if you plan to use an automatic trans.
 
..I guess I am not surprised..Chrysler made some high reving outboard motors for years...my BIL built a 8 foot ( 1 piece of ply for the bottom) hydroplane ..it looked like the pic below. The Chrysler was the only motor (it was old then and I am talking very early 70s) that could rev that high and stay together...he went through a Merc and a Johnrude...

View attachment mBuXbjt3CK1369690422.jpg
 
EL5DEMON340 said:
If it's a runner great if your going to rebuild it have it sonic checked, boat motors can have bad erosion and a lot of rust in the water jackets, a lot depends on how much use and if it was properly winterized
Click to expand...

Even more so, in salt water.
 
wow thanks for all the input.i do have a 360 i going to pull some parts from.i could not find the .wish me numbers off the heads .its not a super bee 3 its a 340 cast in 73 on the night shift.it say on the front of the motor that the rotaion is clock wise.i took pics and will try to post them .thanks agin for everyones input wish me luck.tigey
 
I have a 16' Correct Craft mustang with a reverse rotation 318- 235hp. Also have another one with a Holman Moody 302.
I'm thinking of putting a trailer hitch on the Dart so I can take the boat to Moparfest
 
My uncle ha a Penn Yan 26ft cabin cruiser in the late 70's that had reverse rotation 340. When I think back it was amazing that the little 340 moved that heavy barge as fast as it did. He also had a 19 ft donzi with 350 gm that wasn't much faster.
 
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