1972 F25 Repower Question

vabeach1234 · Post by **vabeach1234** » Mon Aug 01, 2005 4:55 pm

I currently have a 1972 F25 Trojan Express. The rebuilt Chrysler 318 that was put in in 1994 has pretty much given up. The motor is a 1972 model. I have Paragon transmission with a V-Drive setup. The motor is raw water cooled. I would like to repower with a Chevy 5.7L 260 HP. The 5.7L motor seems to be more widely used and parts seem to be more available than the Chrysler. Plus I get more HP. My question is: Will the engine fit under my cockpit deck? Do I have to replace the transmission also? The Chrysler 318 has log style exhaust manifolds with elbows on the end to discharge the exhaust, most of the Chevy 5.7L seem to have riser type exhaust manifolds that look a lot higher than the Chrysler. Also I believe the angle between the prop shaft and the transmission is 20 degrees. If I go to a 15 degree that would lower the engine a little. Is that a way to make it fit. Any comments would be greatly appriciated. Thanks.

Ken
Norfolk, VA

Tom Scott · Post by **Tom Scott** » Tue Aug 02, 2005 12:55 pm

Hi Ken:

I have an F30 1976 model with twin Chyrsler 318's. My boat mechanic has told me when I repower that I should go to Chevy 350's as well. I ask him if I would have to change the transmissions and he told me no. The standard factory Trojan Velvet drive 1:1 works fine with the Chevy 350.
I hope this helps.

Good luck
Tom

vabeach1234 · Post by **vabeach1234** » Thu Aug 04, 2005 8:57 am

Thanks of the reply Tom. My concern is will the motor if under the cockpit floor or do I have to raise the floor. The engine access door is extremely close to the flame arrestor on the Chrysler 318, in fact it has an indention for the flame arrestor. I'm concerned that a new Chevy based marine engine will not fit under the floor. They look taller than the 318's. I was just wondering if any one has done this repower before, switching from a 318 to a 5.7L in a 1972 F25.

Thanks.
Ken

trojan_man · Post by **trojan_man** » Mon Aug 15, 2005 10:32 pm

I have a 1978 F-25 and it had the Merc 228 originally, now it has the 260. It fits fine, but I don't know what your deck looks like. Mine is f-glass, if yours is wood, It may be different. Good Luck

vabeach1234 · Post by **vabeach1234** » Fri Aug 19, 2005 4:31 pm

Trojan Man,
My deck is fiberglass also. Do you have a V-Drive or Striaght Inboard?

Here's a picture of the cockpit.

http://putfile.com/pic.php?pic=8/23015320136.jpg&s=x2