4:11 ratio vs. 3:78

[daveymc29]

I replaced my 4:11 with 3:54, then switched from 21 inch to 16 in. wheels. I have a 26% Mitchell and this works well for me. That being said, I talked to Mitchell after the swap and he told me it would have been better had I brought him the OD and had him switch the gears from 26% to 36% and leave the 4:11 in the car. That was his thinking and I had to agree. With the 16 inch wheels and the 3:54 rear and the 26% Mitchell in direct i"m about the same as 3:78 with 21 inch, at 55 I;m fine with this set up, but could have saved myself a load of work and cost of the 3:54 gear for about the same outcome and changing the Mitchell to 36% wouldn't have cost as much as the gears and bearings I bought.

[katy]

So now I question the "chalk mark at 12'oclock turn the engine twice ratio check".....

W/one wheel jacked up, chalk mark at 12 o'clock, turn the engine twice, 4-1 ratio would put the chalk mark back at 12 o'clock. With a 4.11-1 ratio the mark won't make it back to 12 o'clock, with a 3.78-1 ratio the mark will go past 12 o'clock., Simples.

[Mitch//pa]

Originally Posted by katy

W/one wheel jacked up, chalk mark at 12 o'clock, turn the engine twice, 4-1 ratio would put the chalk mark back at 12 o'clock. With a 4.11-1 ratio the mark won't make it back to 12 o'clock, with a 3.78-1 ratio the mark will go past 12 o'clock., Simples.

i will add to put the trans in 3rd gear , removing the plugs makes it easier to turn

[SSsssteamer]

I changed the gear ratios from 3.78 to 3.54 in my '30 Phaeton and also in my '29 Tudor. I drive in the hills of the Pacific Northwest and the 3.54 was a best choice for me. I still can drive at 65 mph on the interstate.

[katy]

i will add to put the trans in 3rd gear , removing the plugs makes it easier to turn

Both good points. The test wouldn't work too good in neutral or one of the lower gears.

[Bruce Adams]

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i might be missing something but if you said you are having the engine rebuilt, why not consider a high compression head, touring cam, and overbored valves and such that the rebuilders include in their touring engines? My touring engine with stock rear end will do 60 mph, plus any time I want.

[1955cj5]

Originally Posted by Bruce Adams

i might be missing something but if you said you are having the engine rebuilt, why not consider a high compression head, touring cam, and overbored valves and such that the rebuilders include in their touring engines? My touring engine with stock rear end will do 60 mph, plus any time I want.

Hi Bruce,

You are not missing a thing.....I'm missing the $1K it takes to do all those things...this truck was basically free to me, but I've already spent a reasonable purchase amount on it....

But, I am getting insert bearings, SS valves, adjustable lifters, new pistons, rods and of course rings and all those necessary little things like an oil pump/distributor drive...sure-nuf laminated cam gear etc...

A high compression head can be added later if needed.....

The engine should be ready next week...!!!

[1955cj5]

Originally Posted by katy

W/one wheel jacked up, chalk mark at 12 o'clock, turn the engine twice, 4-1 ratio would put the chalk mark back at 12 o'clock. With a 4.11-1 ratio the mark won't make it back to 12 o'clock, with a 3.78-1 ratio the mark will go past 12 o'clock., Simples.

I think the test is legitimate....

I think the error was in my interpretation of the results...

My mark went to about 11 O'clock....so 3:78 is is!

May this thread RIP......