HELP! Is a 1980, 125 Chrysler Powerhead the same as a 1991, 120 force?

[Jasper8301]

I'm thinking about buying a used powerhead for my 1991 bayliner. The 1991 120 Force powerhead is shot but I can use all of the external componets. I found a 1980 125 chysler powerhead and the owner swears it's the same block, and that it will bolt right on to my L-Drive and that I can use all of my externals.... is this true,,, or do I have to make a bunch of mods??? is it worth $150.00 with 125 lbs. compresion on all cylinders ???

 

[pnwboat]

Re: HELP! Is a 1980, 125 Chrysler Powerhead the same as a 1991, 120 force?

You need to check the number of splines on your crankshaft where the drive shaft connects. Many of the L-Drives had 13 splines. The majority of the regular 125 and 120 outboards have 15 splines. Everything else will more or less interchange.

 

[Frank Acampora]

Re: HELP! Is a 1980, 125 Chrysler Powerhead the same as a 1991, 120 force?

If the 1980 block was a distributor engine, then your electronics will not mount on top without modifications.

The distributor engines had the top seal carrier/alternator stator mounted with four bolts and the block is about 1/8 inch higher.

If the 1980 block had Prestolite non distributor ignition, then everything will swap.

Again, as in the above post, check the crankshaft spline count.

HOWEVER: The 125 is a 3.3125 bore X 2.875 stroke engine while the 120 is a 3.375 bore X 2.80 stroke engine. The 120 seems to perform a little better because of the large bore. You MAY notice a small drop in performance with the 125-- Just my opinion---

It is possible to swap crankshafts if you really want the 125 block, but since the porting is different, there will be a loss of performance.