Chrysler AceCrown info wanted

[jmd]

Looking to repower a twin engi

Looking to repower a twin engine 24' Shephard. Currently has twin Aces with not enough power to push the hull. Researching options but would like to know existing specs. Weight and torque are needed to figure comparable values. The 140 hp Crown option work but the Aces at 105 hp just don't cut it. Weight and torque if someone has a manual. Thanks

 

[51lyman]

"Jim; These numbers are from t

"Jim; These numbers are from the mid/late 50's; the Chryslers from around 1951 and earlier (like my 1950 125 h.p. M47S) had a slightly smaller bore and lower horsepower.
Ace M46 230 cu.im.; 95 h.p @3200 rpm
Ace Special M46S 230 cu.in.; 110 h.p. @3600 rpm
Crown M47 265 cu.in; 125 h.p. @3600 rpm
Crown Special M47S 265 cu.in; 135 h.p. @3600 rpm
I think I have the power curve charts as .pdf files if you want them. Lots more Crowns than Crown Specials around, though Shepherd used the more expensive Crown Specials as you can see from those boats still around.
Dry weight for an M46 or M46S with a Vee-drive (Shepherd??) is 821 lbs.; a M47 or M47S with Vee drive is 895 lbs. The M46 is 53 3/8" long; the M47 is 55 5/8" long. The Crown Special M47S has two carbs that stick out a bit, so it's wider (about 4 inches?).

I'm surprised to hear that Shepherd underpowered one of their boats - they were known for the highest quality boats and well-heeled owners. Have you tweeked those Aces (good compression, electronic ignition, etc.?). Andrew can probably sell you an original Chrysler Ace/Crown manual from this website."