Chrysler racing outboards

[John Schubert]

That's at the Antique Boat Show Tomahawk WI, not mine or anyone's shop.

Here is the link for the pictures taken at the AOMCI International meet this year in T'Hawk. Click on the one for the Arena, there you will see several race engines & boats from the 40's & 50's.
https://www.spanagel.net/Event-Photos/T ... -Nationals

[Mark75H]

Somebody really thought the steering bar gas tank needed a passage thru it for the above water exhaust relief????

[olboatman]

Somebody really thought the steering bar gas tank needed a passage thru it for the above water exhaust relief????

And I use a cool can for my fuel when possible!
Gary

[Dave S]

Sam ... that is where ya hide the turbos.... in the tank.....no one would ever look .....

[FMP]

at speed

[largecar91]

That's a short boat! Looks like an old SE or mod 50 boat

[wuhbbr]

Bill runs one of his 15' E&T's w/ his stacker.

[Dave S]

short boat less air.... like a 15 viper with a ... v6 of your desires......

[gmjim]

Can anyone offer an opinion on the best year/horsepower Chrysler/force 4 cylinder power heads as a basis for a modified engine?

[FMP]

I like the 103 ci , 3.375x2.875" Chrysler 140. Others like the 96ci 3 5/16x2.8" which was the original ci for the 70s stackers , others like the 99ci 3.375"x 2.8" 115hp which was basically the discontinued 77 135hp. TC carbs are a must for all above. The earlier Force are still Chrysler except for ign. The later swapped Merc rods and slightly different x flow pistons and crank but same ci with updated TC carbs, Merc ign, four petal cages. They run well but still behind a 140.
Some say the original 2.8" stroke turns more rpm. All depends on the what you're trying to do and hull.
Adapters, the later Force are Merc leg motors and crank which will not bolt to a earlier Force or Chrysler leg or drive shaft.
The later Force 120 does have potential with additional porting and compression etc. The engines are a good start for modifications if you have a Merc style mid , lower. If you have one put a degree wheel on it and share the stock numbers.
The Chrysler is about 265lbs all in for a 20" , the later Force is heavier.
Another choice is the 150 F5 , 89-90 small bore 124ci , 91-94 big bore 128 ci. Both 2.876" stroke and Chrysler x flow pistons, rods, crank spline. 128ci version has Merc ign. 20" is about 334 lbs.

[vintage v4]

That's a short boat! Looks like an old SE or mod 50 boat

Probably built by Hering as a Mod 50 but had a Formula 100 V4 OMC on it at one time.

[FMP]

Probably built by Hering as a Mod 50 but had a Formula 100 V4 OMC on it at one time.

I'll ask again but the OMC seems right

[gmjim]

I like the 103 ci , 3.375x2.875" Chrysler 140. Others like the 96ci 3 5/16x2.8" which was the original ci for the 70s stackers , others like the 99ci 3.375"x 2.8" 115hp which was basically the discontinued 77 135hp. TC carbs are a must for all above. The earlier Force are still Chrysler except for ign. The later swapped Merc rods and slightly different x flow pistons and crank but same ci with updated TC carbs, Merc ign, four petal cages. They run well but still behind a 140.
Some say the original 2.8" stroke turns more rpm. All depends on the what you're trying to do and hull.
Adapters, the later Force are Merc leg motors and crank which will not bolt to a earlier Force or Chrysler leg or drive shaft.
The later Force 120 does have potential with additional porting and compression etc. The engines are a good start for modifications if you have a Merc style mid , lower. If you have one put a degree wheel on it and share the stock numbers.
The Chrysler is about 265lbs all in for a 20" , the later Force is heavier.
Another choice is the 150 F5 , 89-90 small bore 124ci , 91-94 big bore 128 ci. Both 2.876" stroke and Chrysler x flow pistons, rods, crank spline. 128ci version has Merc ign. 20" is about 334 lbs.

Just the guy i was hoping would reply, and a great answer, thankyou.
so does a late 120 need more compression and higher ports to match the 140?
i will port and rebuild whatever i use and will be on a light v hull, and i have a lot of merc gear so any compatibility is great, especially lower units...
do early 140 heads fit on the later force?

[FMP]

A little more duration on the exhaust or just area by squaring if on a heavier hull. Transfers area, squared on centers and inner side of the outer ports, leaving far outside corners round worked well for the Force race motors, same applies to the Chryslers. Transfers could be raised a bit depending on the stock duration numbers, exhaust and transfers measured using the degree wheel first. Leave the outside port ears at the sleeve, they help direct fresh charge to the center of the deflector.
Chrysler heads are big and small bore, squared corners rectangular shaped head are the later and cool a bit better , the other is the earlier. Don't exchange big bore for small, just cut for psi. Earlier Force can use Chrysler head, they did change the shape again, late Force had slightly different chamber to match the later Merc x flow design.
The Chryslers are 165 psi, the Force a bit less 145-155 or less and not even based on design, a bulletin was issued, except first few years from Chrysler. I run 172psi on 93 with lots of timing and more jetting with 3151 Wisecos. Not sure how much the later Force will tolerate on pump gas but 165 should be fine with jetting.
Chests are a bit different, front case seems a bit tighter, tuner is different between late Force and Chrysler.
Lowers are one or the other, different legs. Powerflow side bullet Chrysler doesn't bolt to later Force. F5 typeA, B, C or D will bolt to 77/78-84+ Chrysler mid, not earlier two piece lower unit leg 60s-76/77.
Like anything older if you are pulling it apart check the ring pins , I have pulled them apart and found the pin moved, piston chipped and just ready to wreck the cylinder.
If you find an F5 that's close by have a look. They take some more work to mod because of the ex stuffers etc but five holes always gives more.
But a well built Chrysler or F4 will turn good rpm and perform.
Minimum 40:1 !

[olboatman]

Now there is some hard to find info right from
S&Fs Chrysler guru himself.
Gary