chrysler questions

[novicetech]

hello gentlemen,<br />I have a couple of quesions about my 1971 70 Hp chrysler outboard. I am attempting to rebuild this outboard and there is some scoring in the cylinders and i want to have the cylindres bored.<br />There is a place in pennsylvania that claims to simulate head torque when they bore the cylinders, is this very important? The bore and stroke on the 70 hp 75 hp and 85 hp are all the same. Does anyone know how chrysler got the extra hp and compression? I would like to build this motor to be around 80 hp, which is the maximum hp rating for 15 Thundercraft 1979 model. All comments and suggestions are welcome.<br /><br />Thanks,<br />Novicetech

 

[WillyBWright]

Re: chrysler questions

One thing you might want to consider before overhauling that motor. The electronic ignition on that motor is no longer available in any form as far as I know. If you overhaul it this year and your ignition goes out next year, that's a whole lot of money for a motor that you still can't use. Besides, you'd need do more than boring it oversize to get any significant horsepower increase. I wouldn't want to speculate whether or not 85Hp parts would work, or be enough to accomplish the task. I wouldn't do it, myself.

 

[seldont]

Re: chrysler questions

would most likely need to change port timing to get 85 hp. (expensive) propbaly carb work and maybe reeds as well. It is important to use a torque plate when boring so the bore will be the same when the engine is assembled and the head torque in place.