5.7V8 with a 1.84 alpha one gear ratio

[Bondo]

Hello all i have a question regarding Ricks comment mentioning that there is going to be little to no difference between a 5.7 on a 1:1.84 with a 23 inch prop and a 5.7 on a 1:1.47 with a 19 inch prop, all else being equal.

It seems there would be an efficiency problem by running the 5.7 on a 1:1.84 Maybe a little less efficient on top end, or terribly inefficient some could say.

Any ideas why would that be? Perhaps due to propeller slip? Why has the gear ratio been reduced in the first place for larger engines instead of pitching prop?

I'm considering retrofitting a 5.7 on a AGen1 leg which was formerly used with a 4.3 (1:1.84) but perhaps its not a good idea

Ayuh,...... Some years ago, I did some prop testing, as I love the ole Torque Shift props,..... they run from 11" pitch at idle, to whatever pitch you set it too, at Wot,.....
On my ole fishin' barge, a '74 Starcraft Islander, I'd stuffed a much newer 4.3LX into,.....
I'd run for years with a 1.65:1 geared Alpha 1, but I had to really hold the prop back from shiftin' to higher gear, by crankin' down pretty tightly the adjustin' screws, which is 'ell on the cams,.....
I could troll Walleyes all day at 700 to 1100 rpms,1/2 to 1.5 mph, 'n top out at 4800 rpms, 42 / 43 mph,.....
So, I figured what the 'ell, I've got an ole 1.98:1 drive kickin' 'round, 'n the prop likes the top pitch closer to 26" compared to the 20" it was at,....
So, I slapped the drive on, 'n set the prop to 26" pitch, top gear,....

It made alota noise(straight pipes), but would barely pull 25 / 30 mph,....

A 350 needs a 1.50:1, unless pushin' a boat bigger than 26', 28' long,.... then a 1.65:1 might better,.....
The 1.84:1 would be suited to pushin' a Freighter,....

 

[flashback]

Ayuh,...... Some years ago, I did some prop testing, as I love the ole Torque Shift props,..... they run from 11" pitch at idle, to whatever pitch you set it too, at Wot,.....
On my ole fishin' barge, a '74 Starcraft Islander, I'd stuffed a much newer 4.3LX into,.....
I'd run for years with a 1.65:1 geared Alpha 1, but I had to really hold the prop back from shiftin' to higher gear, by crankin' down pretty tightly the adjustin' screws, which is 'ell on the cams,.....
I could troll Walleyes all day at 700 to 1100 rpms,1/2 to 1.5 mph, 'n top out at 4800 rpms, 42 / 43 mph,.....
So, I figured what the 'ell, I've got an ole 1.98:1 drive kickin' 'round, 'n the prop likes the top pitch closer to 26" compared to the 20" it was at,....
So, I slapped the drive on, 'n set the prop to 26" pitch, top gear,....

It made alota noise(straight pipes), but would barely pull 25 / 30 mph,....

A 350 needs a 1.50:1, unless pushin' a boat bigger than 26', 28' long,.... then a 1.65:1 might better,.....
The 1.84:1 would be suited to pushin' a Freighter,....

I don't feel so bad posting in an older thread anymore! LOL

 

[Bondo]

I don't feel so bad posting in an older thread anymore! LOL

Ahhhhh,..... no ship,...... didn't see it,......

I'll lock it up,...... Thanks fb,....