TKO 600 final drive gear

[Eespensen]

What 5th gear are people running? .82 or .64?

[CDXXVII]

I am running the TKO 600 Road Race .82 mated to a Ford Racing Z427. I am really happy with it and only very rarely do I wish I had a true overdrive gear. You need to keep in mind your intended purpose. For me with 3.31 rear end gears I am at 2300 RPM's in 5th for 65 MPH which is cruising speed. Sunday I was cruising at 3000 RPM's and the engine sounded so nice that I almost failed to realize that I was going 85 MPH in 5th.

Here is a good tool that lets you plug in your numbers to see where your engine will be when comparing RPM to MPH

www.tremec.com/calculadora.php

If fuel economy is of any concern and you have plenty of torque I would go with the .64. If your intent is performance and fun then I would go with the .82.

[edwardb]

As CDXXVII alluded to, the choice can't be made without other considerations. What diff gears are you running? What engine and what are your target RPM's? What is your intended use for the build? Every combination has it's pluses and minuses.

I did the .82 TKO final drive with a strong DART stroker 347 and 3.27 diff on a previous build. I liked the slightly longer 1st through 4th with the 3.27, and the .82 5th gear could be used for more than just an overdrive. For non-highway cruising, it was another available gear without the big drop-off from 4th to 5th. The disadvantage was cruising on the highway was a somewhat higher RPM than I wanted. Typically 2,700 - 2,800 RPM. Plus even though the 347 was a good strong engine, I missed the snap of the 3.55 diff I had previously.

For my latest build with a Coyote, used the .64 TKO and 3.55 diff. I like this combination a little better frankly. The only downside is the gap between 4th and 5th. Really only useful as a highway cruising gear. But the Coyote loves to rev, so 4th is just fine for non-highway cruising.

[Eespensen]

Planning a 347 Dart small block with 3.55 rear gears. Thinking I'd like a highway gear for cruising

[Jim1855]

Was running 3.27 with the .64od. 2,200 at 80 for highway cruising. New build will be 3.31 if I can get them and then the same engine trans combo. 427w motor.

[JRL16]

.64 here.

[Bobby Doug]

.64 X2, 3.31 rear axle. I guess it depends on where you live. Here in KS even our two lane roads are 65-70 mph and our interstates are 75 mph. So the overdrive was important. My engine is turning 2K rpm at 70 mph, it will do the slower speeds in 5th, but I have to roll on the throttle increase. If I lived in the NE where the two lane roads are 55-60 and 65 on the interstate then I would have done the .82.

[GoDadGo]

Does anybody have any experience with the Richmond 5-Speeds?
Their final drive splits the difference at .77 Overdrive.

https://www.summitracing.com/search/brand/richmond-gear/product-line/richmond-gear-super-street-5-speed-transmissions-with-overdrive?autoview=SKU&ibanner=SREPD5

I'm just throwing this out there because my 5th gear is a .75 Overdrive and works well in my daily driver and MK-4 so the Richmond unit is quite close .77 compared to the TKO units.
We all know that the Richmond transmissions have been out there for quite a while; however, I have no idea if they are any good or not.

[2bking]

I have a Coyote, 3.55 rear gears, TKO 600, and started out with the .82 fifth but after some freeway driving I decided to install the .64 ratio. I like it much better with the slower engine rpms and quieter exhaust. At 70 mph the engine is turning about 2100 rpm and has enough torque for most of the acceleration needed in traffic. Seldom do I ever shift to fourth after getting up to speed on the freeway.

[wareaglescott]

.64 for me as well with a Coyote and 3.55 rear end. Same comments on drivability as King mentioned. Very pleased with it.

[walt mckenna]

I have a Coyote, 3.55 rear gears, TKO 600, and started out with the .82 fifth but after some freeway driving I decided to install the .64 ratio. I like it much better with the slower engine rpms and quieter exhaust. At 70 mph the engine is turning about 2100 rpm and has enough torque for most of the acceleration needed in traffic. Seldom do I ever shift to fourth after getting up to speed on the freeway.

My 4.6 does not have the torque of a Coyote, but I see the same benefits with the .64 and 3:55 combination as Mr King. Mine also sees track time and I have never had the need for an .82 on the tracks that I frequent.

[DaveS53]

65 mph is not cruising speed where I live. I drove 360 highway miles from Loveland to Pueblo and back this weekend, going 80 mph whenever possible. In my car that's 2100 rpm. If the speed limit is 75, you better stay in the right lane if you're under 80. I had to move over for faster drivers quite a few times.

[GoDadGo]

65 mph is not cruising speed where I live. I drove 360 highway miles from Loveland to Pueblo and back this weekend, going 80 mph whenever possible. In my car that's 2100 rpm. If the speed limit is 75, you better stay in the right lane if you're under 80. I had to move over for faster drivers quite a few times.

That's How They Roll Where I Live!

85-90 MPH is the average commuting cruising speed with triple digit speeds not that uncommon on the Twin Span across Lake Pontchartrain.
If any of you have found yourself driving between Slidell and New Orleans during rush hour, then you'll have experienced our version of the Salt Flats.
Heck, I need the extra gear just to keep up and try to avoid the Twin Span on my motorcycle because I run out of gear.

1995 Corvette > 3.55's Rear Ratio
MK-4 Roadster > 3.73's Rear Ratio
Both have the same transmission.

1st > 2.68
2nd > 1.80
3rd > 1.29
4th > 1.00
5th > 0.75
6th > 0.50

[RoadRacer]

That's How They Roll Where I Live!

85-90 MPH is the average commuting cruising speed with triple digit speeds not that uncommon on the Twin Span across Lake Pontchartrain.

Pfshhhh Steve, we have a road here with the officially fastest speed limit in US. Everything bigger in Texas :)

Great thread though, I haven't bought my TKO yet.

[DaleG]

.64 for me as well with a Coyote and 3.55 rear end. Same comments on drivability as King mentioned. Very pleased with it.

X3 here.

[Avalanche325]

347 (500hp), 3.31:1, and .82

If fuel economy is a concern, you bought the wrong car. :-)

[johnnybgoode]

414 CID with 520 ft/lbs and 3.55. Went with the .64 very happy I didn't do the .82

[Joe Campbell]

349 (.40 over 347) with a .565/.575 cam and 2000cc heads. It doesn't like to cruise as low as 2000rpm. My combo is .64 and 3.73 and it could almost use a bit more gear to stay in this motor's sweet spot above 70mph, or I might have been better off with the .82.

[initiator]

A fuel-injected engine is going to remain happier at lower RPM than a carbureted engine, due to better torque production from improved fuel atomization.