TKO600 .82 or .64

ChrisL · #1 (**permalink**) 11-06-2004, 02:19 PM

Ok,I am going to get a TKO600 but I am undecided on weather to get a .82 or the .64 5th gear . I will not be doing any type of racing just cruising and playing on the street. I am concerned that the .64 may be too much of a drop in RPMs but for the highway it may be ok . I am running a 3.55 posi rear and 295/50/15 rear tires.The motor should be about 340 RWHP. I have gone and ran my numbers on the gearing calculators but I need some input from a few who may have one or the other ,let me know.
Thanks Chris

CSCHWER · #2 (**permalink**) 11-06-2004, 02:38 PM

A 0.68 with a 3.91 rear is just about right. With a 3.55 rear I would go with the 0.82. Run the numbers.

Chet

ERA649 · #3 (**permalink**) 11-08-2004, 04:35 AM

I have a TKO with .62 and 3.31 rear and I find 5 th is only good on the highway @ 65 + mph.

Ron61 · #4 (**permalink**) 11-08-2004, 04:57 AM

I am running the 3:27 gears and a .6 split and I agree with ERA649. The 5th gear is strictly a freeway gear and only then when not in heavy traffic. At 70 MPH I tach 1900 RPM. Way to low in the engines power band to do anything but cruise. I think that if I had a chance to do it over I would go to the .8 with the gears Iam running. Gears below 3:55s I think would be ok with the .6 split.

Ron

DonC · #5 (**permalink**) 11-08-2004, 09:56 AM

Chris:
.82 fifth, 3.07 rear end, 17" wheels/tires. 2300RPM@70MPH in 5th. Wind noise is louder than the exhaust at that speed and about 15MPG with a 428FE.
DonC

mikiec · #6 (**permalink**) 11-08-2004, 10:18 AM

I'm running a t-5 with .62 5th. 3.27 rear gear. It is great for freeway cruising. After all, isn't this what 5th is for? Lower cruise RPM, increase fuel mileage. When I need to pass, it's no big deal to down shift to 4th.

Mike

Chaplin · #7 (**permalink**) 11-08-2004, 10:58 AM

Quote:

Originally posted by mikiec

I'm running a t-5 with .62 5th. 3.27 rear gear. It is great for freeway cruising. After all, isn't this what 5th is for? Lower cruise RPM, increase fuel mileage. When I need to pass, it's no big deal to down shift to 4th.

Mike

Mike-
Depending on the specs of your cam and the rear gear you are running, the .62 5th can drop you too far out of the engine's powerband to run efficiently- which I think is what Ron and ERA649 are referring to.

I have the .82 5th with a 3.31 rear and at 70 I think its turning about 2400, which is just pretty good. Even at that low rpm, the motor has enough torque that I can pass without a problem simply by pressing the gas pedal- no need to down shift. If I had the .62 5th, I think the motor would be lugging too much and I would have to down shift. But it really depends on your cam and rear gear ratio.

bret a ewing · #8 (**permalink**) 11-08-2004, 11:58 AM

See if this makes sense.........

The TKO 600 with a 3.55 rear ratio is very close (within 2 mph across the gear and rpm spectrum ) to a wide ratio toploader and also utilizing a 3.55 rear ratio. This was the generally the standard ratios back in the '60s.

So, depending on your cam,

You can either run: 52mph @ 2000rpm with a .82 5th gear
or..
You can run: 67mph @ 2000rpm with a .65 5th gear

Hope this helps.

Regards, Bret.

thorconstr · #9 (**permalink**) 11-08-2004, 03:57 PM

Chris, I have a TKO 600 w/ .82 OD and 3.54 rear gears. 70mph on the freeway is 2600 rpm. I really like the "road race" feel of this gear selection.

ERA649 · #10 (**permalink**) 11-08-2004, 04:42 PM

Bret,
I think it's 58.6 mph in 4th and with .82 63 mph @ 2000.
and everyone knows I never drive faster then 65 mph- the legal limit in NJ.

Running the engine less then 2000 is lugging it.

bret a ewing · #11 (**permalink**) 11-09-2004, 04:05 AM

ERA,

TKO 600 with .82 5th gear
295-50-15 rear tires
3.55:1 rear axle ratio

2000 rpm @ 1st gear - 15 mph
2000 rpm @ 2nd gear - 23 mph
2000 rpm @ 3rd gear - 34 mph
2000 rpm @ 4th gear - 43 mph
2000 rpm @ 5th gear - 52 mph

Regards, Bret.

Ron61 · #12 (**permalink**) 11-09-2004, 04:45 AM

Chaplin hit my problem right on the head. My engine doesn't even get past the lugging stage until I get around 2500 RPM. I could change tire sizes and help a little but just put up with this as when there isn't a lot of traffic I keep it above 2000 RPM which also puts me above the 70MPH speed limit. I don't do much freeway driving as I prefer the back roads and there I hardly ever use 5th gear. My big block has 3:91 gears and that is a whole other story. Both engines have rather radical cams but I did cut the one in the big block back from 312 duration and .630 lift to 286 duration and .560 llift with a change in overlap and I like it much better.

Ron

Jack21 · #13 (**permalink**) 11-10-2004, 05:20 PM

Chris L,

Given your 340 or so RWHP (warm 302, or 351W), and cruising and playing on the street intended use, I think you'd be happier with the T-5Z (2.95 1st) for this application.

Shifts like a Honda, and the gear ratios are right. You'll have to get it from a trans shop that can swap out the .62 OD gear for something a little taller like a .73, or .80. And it fits any Five Oh 5 speed bellhousing, the cable clutch fits.

I got mine new, blueprinted, with the .73 OD, and have 3.55 diff gears from Liberty Racing Transmissions in Livona, MI. Put a Hurst shifter, added Hurst Classic shifter ball, fed it Mobile 1 ATF, and 3 years, 16,000 miles, still going strong. I love the way this trans goes up and down gears.

Tremec T-600 may be overkill, and substantially more expensive.

driver · #14 (**permalink**) 11-13-2004, 04:15 PM

I have a Keith Craft 331 and 3.73 rear ratio . My car is perfect with the .082

Chaplin · #15 (**permalink**) 11-13-2004, 04:21 PM

Driver-
Just checked out your gallery. Don't think I've seen an spf street version before. Very nice.

driver · #16 (**permalink**) 11-13-2004, 04:25 PM

THANKS!