Swapped internals?

[rdj59]

Hi, i was looking at my drive to get the number and discovered that it was originally behind a 140hp motor. Somebody just restickered over the original sticker. The boat is a 74 22' searay with the ford 233hp. The drive tag read 1.98r and the drive i'm supposed to have is 1.32r. The number is 4758500. I'm wondering if someone changed the internals out to the proper ratio. I did have a chance to run it before i put it away for the winter. With a 14x19 prop on i was turning 4200 at wot which is perfect as that's my max rated rpm. Fish finder said i was doing 46 mph but i doubt that's accurate. Is there a difference in the 4cyl outdrive vs 8cyl outdrive besides ratios? I'll be doing new water pumps, belows, gimbal bearing and trim sender in the next month. Is checking the ratio on an outdrive the same as checking it on a rear end. Rotate the prop and count the number of times the input shaft spins?

Thanks,
Jeramie

 

[Bondo]

Re: Swapped internals?

Ayuh,...

My guess is somebody used the 1.98:1 caseto build a 1.50:1 drive for your boat...
1.50:1 is the Right ratio...
1.32:1 was only used with the BBCs...

 

[Don S]

Re: Swapped internals?

The Ford 233 engine is a 351 Ford, the drive (also called a 233) had a gear ratio of 1.32: 1.
It's very possible the gears were replaced in a 140 housing. The only thing that changed in the housing was the decals. Had you had a 1.98 and the same prop, you would be running at 5000+ rpm.

 

[rdj59]

Re: Swapped internals?

That's what i thinking/hoping. The guy i bought it from said it was all rebuilt about 10 years ago and even found the receipt in a box of papers. When i got the boat the registration expired in 03. The lower unit looks to be newer yet as it still has all the tags on it and looks newer. I just took everything with a grain of salt, the guy seemed like kind of a burn out. Best part is when we were talking about the motor and he was playing dumb. His neighbor shows up and says, "he found the motor huh". The motor was full of water and needed to be rebuilt. Everything pressure tested good so i rebuilt it and was out on the water 7 days later after i bought it. Worked on it as i used it and about 3 weeks later i had a nice hole in the top of my left riser. Yippe! Bought with the intentions of making it a new boat. I liked the lines and the price was good.

Jeramie

 

[Bondo]

Re: Swapped internals?

had a gear ratio of 1.32: 1.

Really,..??
I'd never would have believed a 351 needed the 1.32s,....
They aren't any torqueyer than a 350 Chevy,..??....

 

[mkast]

Re: Swapped internals?

Really,..??
I'd never would have believed a 351 needed the 1.32s,....
They aren't any torqueyer than a 350 Chevy,..??....

Don't be to sure about that, Mercruiser thought so.
Didn't the 255 hp 351 also use 1.32:1 ratios?

 

[Don S]

Re: Swapped internals?

Really,..??
I'd never would have believed a 351 needed the 1.32s,....
They aren't any torqueyer than a 350 Chevy,..??....

Always seemed odd to me too, but that is what Merc used with them for a few years, then they dropped Fords like a hot rock.

 

[Don S]

Re: Swapped internals?

Didn't the 255 hp 351 also use 1.32:1 ratios?

The 255 used the TRS drive

 

[mkast]

Re: Swapped internals?

The 255 used the TRS drive

Then it must have been a home built I ran into.
255 hp 351 with a 1.32:1 with a R drive.

 

[Bondo]

Re: Swapped internals?

Alllrighty then,.... Today is a Great Day,...

I've got my Learnin' something for the day, outa the way, for today anyway....

 

[rdj59]

Re: Swapped internals?

I know when i was researching out stuff and ran across the ratio of the drive i needed to do a double read. I don't understand why the would use such a ratio with the 351. The motor does have some torque. First time out with the boat ever to break in the motor i gave it half throttle and it threw me into my seat. This was with a 16x16 on it. I kinda hoped up the motor, tried to keep it closer to a stock like motor as possible. When i rebuilt it i went with flat top pistons w/2 valve reliefs(worked out to 9.9:1 comp), cam with the specs of 214/228 on a 114 lobe sep, ported out the D00e heads(shaped around the valve guides, ground out the ridge in the exhaust ports, port matched the intake port), still running the factory intake and 2brl carb. I'm upgrading to a 4brl intake and 600-650 cfm holley, and roller rockers. These should make it perform a little better. It seemed to run a little funky in the midrange and i'm pretty sure its carb related. When i rebuilt the carb it was in pretty ruff shape. I was happy it even worked.

Jeramie