Mileage Difference: SM465 vs. TH400

[dhdescender]

Anyone have a general idea how much more fuel a TH400 would burn compared to a SM465? I think I'm planning to use a manual floor shift on my TH400.

Anyone driven a truck with a TH400 and then one with a SM465 that was essentially built the same?

 

[mud390]

I have a T400 behind a mild 350 and it eats a lot of power. I've read somewhere that it takes 45hp to turn the T400 and only like 15 to turn a T350. Strong tranny though. Don't know about milage. Haven't had a SM465 before. Hope that helps.

Kris

 

[chulisohombre]

i think they are both 1:1 final ratio.the 465 wont slip because of the clutch and pressure plate.the th400 will slip depending on what stall converter you have and also how worn out the clutches and bands have.you dont really have to worry about burning up a 465 either.no extra plumbing to worry about also.do yuo have a 465 now and want to switch to a 400?

 

[dhdescender]

I currently have both on hand.

I'm going to have a caddy 500 -> either TH400/SM465 ->203->205

If the Turbo 400 wont slip a bunch, and will run at least close to what the 465 will, then it saves all the effort of drilling the crank for the pilot bearing. all i have to do is swap tail shafts

 

[tRustyK5]

Figure on 10% better mileage with the 465 over the TH400. Even though both have 1:1 final ratio the TH400 always has a little slip, plus it's a power eating pig/forums/images/graemlins/smile.gif Anything eating power is costing you fuel.

The SM465 has no pump to be driven, has no slip when the clutch is out and the only losses be minimal through the tranny. Much more efficient as far as power to the ground as well as fuel consumption.

Rene