1995 657X XP engine in a 1994 GTX

[dalef62]

I am trying to find out what I will have to do to get this engine to work. Bought this engine from a guy who claimed the engine came out of a 1995 GTX, it is a 159 degree valve. I have used the mag and the flywheel from my GTX and I will be using the rotary valve cover from the bought engine and the carbs and carb mount from my 1994 GTX. Should I change the rotary valve to the 147 degree valve or keep it the same 159 degree valve? Will my carbs work? Will my MPEM work? And why is the pulse valve outlet on the cases on the PTO side of the carbs?
Thanks,
Dale

 

[dalef62]

Any thoughts?

 

[wfo speedracer]

I would leave the 159 valve in it, MPEM'S are the same but the 95 model has DESS capability, just make sure you use the complete ignition system off either the 94 or the 95, the parts do not interchange especially the flywheel, it's timed differently

 

[howie099]

I have a 95 GTX with no DESS from the factory and they come with a 657x . So you have a 657x replacing a 657 like the 94s came with. The MPEMs are pretty much the same. I would match the jetting to the 95 GTX and with the stator/magneto you have the 4 wire and 5 wire systems. Pretty sure the 657x had the 4 wire system my 95 GTX does. Exhaust should fit. PTO is the same.

 

[Bills86e]

Each year has a "set" of electronics-stator-flywheel. So you must use the full set. These "sets" will work with either engine. 5 wire/timing VS 4 wire.


Bills86e

 

[dalef62]

OK,
I am using the Stator, flywheel and MPEM from my 1994 gtx and the rotary valve from the 1995 engine. I am using my carbs from the 1994 GTX, will what modifications will I need to make to make it run right or can I just install them as is?
Thanks,
Dale

 

[ski-d00]

The 657 and the 657x are very different engines, cylinders, mpem, electronics, etc. The x motor is closer to the 720. You can't just swap certain parts. The rotary valve is directly tied to the timing and mpem which is very different between the two.

 

[Bills86e]

these are NOT rave valve engines!!!!

 

[ski-d00]

sorry, meant to say rotary valve. nice catch, I'll correct.