TKO 600 .64 vs .82
Le Mans Master
Joined: Oct 2007
Posts: 7,456
Likes: 977
From: RI, Now Franklin/Nashville TN
Not a vette, but i run the .64 OD behind my 496 in my 67 c10. 3.73 gears with 29” tall tires.
I’m glad I don’t have the .82. Big block torque means if i hit an open back winding road I can chug along in OD. Most times I run up to 4th on all the back roads and leave 5th for the 4 lanes. If you only ran at 60-65 you might want the .82 but let’s be honest every drives 70-75.
Honestly it’s the best mod I ever did to the truck
I’m glad I don’t have the .82. Big block torque means if i hit an open back winding road I can chug along in OD. Most times I run up to 4th on all the back roads and leave 5th for the 4 lanes. If you only ran at 60-65 you might want the .82 but let’s be honest every drives 70-75.
Honestly it’s the best mod I ever did to the truck
I just drove a rental Nissan Rogue today from Nashville to Chattanooga TN at a consistent 80-85 for 200 miles just today. ,82OD for most applications would NOT be enough at those speeds to keep the revs lazy....
Last edited by jb78L-82; Dec 19, 2017 at 09:39 PM.
Le Mans Master
Joined: Dec 2009
Posts: 6,397
Likes: 649
From: Saskatoon Saskatchewan
Le Mans Master
Joined: Dec 2009
Posts: 6,397
Likes: 649
From: Saskatoon Saskatchewan
That's what I'm thinking will be the case with my 3.70 rear end and the .67 fifth gear. I think a .75 fifth would be the best compromise as the .82 fifth wouldn't provide enough rpm drop for cruising at 60 mph in fifth and the .67 fifth might be an undesirably low rpm for crusing at 60 mph in fifth.
Race Director
Joined: Jun 2000
Posts: 10,046
Likes: 675
From: FL
That's what I'm thinking will be the case with my 3.70 rear end and the .67 fifth gear. I think a .75 fifth would be the best compromise as the .82 fifth wouldn't provide enough rpm drop for cruising at 60 mph in fifth and the .67 fifth might be an undesirably low rpm for crusing at 60 mph in fifth.
Le Mans Master
Joined: Dec 2009
Posts: 6,397
Likes: 649
From: Saskatoon Saskatchewan
Race Director
Joined: May 2005
Posts: 10,674
Likes: 122
From: Millington Illinois
St. Jude Donor '08-'09
Yep! With a 4.11 it is 10.93 to 1 first gear, close ratios all the way through and 2 overdrives. 6th gear is like a 2.59 rear end. Best of both worlds. Making it fit easily is another story.
Last edited by 63mako; Dec 20, 2017 at 05:28 PM.
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Le Mans Master
Joined: Dec 2009
Posts: 6,397
Likes: 649
From: Saskatoon Saskatchewan
How do you find that 10.93 to 1 first overall gear ratio? My five speed has a 3.27 first and with my 3.70 rear end its a 12.1 overall first gear ratio which I worry might leave me with very little time in first gear before I hit a 5000-5500 rpm or so shift point.
Race Director
Joined: May 2005
Posts: 10,674
Likes: 122
From: Millington Illinois
St. Jude Donor '08-'09
1st 47 MPH.
2nd 70 MPH
3rd 96 MPH
4th 125 MPH
5th 156 MPH
6th 199 MPH
2500 RPM is 60 MPH in 5th and 2600 RPM is 80 MPH in 6th. 2500 is the cruising sweet spot with my cam
Le Mans Master
Joined: Dec 2009
Posts: 6,397
Likes: 649
From: Saskatoon Saskatchewan
So, judging by that if my redline is 5000 rpm I'd be shifting at 35 mph into 2nd.
Thread Starter
Race Director
Joined: Mar 2016
Posts: 14,410
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From: Napa Valley California
I'm not thinking red line shifting, I'm looking at street driving, twisting roads and highway cruising.
A 6 speed would be awesome, but cost and fitment are issues.
I've wanted to jump on the purchase of the SST kit before the new year and get their holiday, year end specials, but it looks like I might just wait and piece this together on my own a little at a time to save a little $$$
Le Mans Master
Joined: Dec 2009
Posts: 6,397
Likes: 649
From: Saskatoon Saskatchewan
That's why I'm trying to stay with a 3.36 rear end gear.
I'm not thinking red line shifting, I'm looking at street driving, twisting roads and highway cruising.
A 6 speed would be awesome, but cost and fitment are issues.
I've wanted to jump on the purchase of the SST kit before the new year and get their holiday, year end specials, but it looks like I might just wait and piece this together on my own a little at a time to save a little $$$
I'm not thinking red line shifting, I'm looking at street driving, twisting roads and highway cruising.
A 6 speed would be awesome, but cost and fitment are issues.
I've wanted to jump on the purchase of the SST kit before the new year and get their holiday, year end specials, but it looks like I might just wait and piece this together on my own a little at a time to save a little $$$
Last edited by Priya; Dec 20, 2017 at 06:49 PM.
Thread Starter
Race Director
Joined: Mar 2016
Posts: 14,410
Likes: 8,213
From: Napa Valley California
Exactly.
That's why I'm looking at the TKO 600 with the .82 and 3.08 rear gearing.
At 65 mph in 4th I'll be at 2470 rpm and in 5th 2025 rpm.
Around town will be tame and roll on at 65+ speeds will be hot with the operating range of my cam at 2000-6000 rpm.
The 496 at 600+ ft lbs torque should still be plenty of fun around town even with the 3.08's.
With a 3.36 I'll only be at 2694 rpm in 4th at 65 mph and 2209 rpm in 5th at 65 mph.
That's why I'm looking at the TKO 600 with the .82 and 3.08 rear gearing.
At 65 mph in 4th I'll be at 2470 rpm and in 5th 2025 rpm.
Around town will be tame and roll on at 65+ speeds will be hot with the operating range of my cam at 2000-6000 rpm.
The 496 at 600+ ft lbs torque should still be plenty of fun around town even with the 3.08's.
With a 3.36 I'll only be at 2694 rpm in 4th at 65 mph and 2209 rpm in 5th at 65 mph.
Last edited by OldCarBum; Dec 20, 2017 at 07:27 PM.
Le Mans Master
Joined: Dec 2009
Posts: 6,397
Likes: 649
From: Saskatoon Saskatchewan
My car with the 3.70 rear and present close ratio 4 speed (2.25? 1st) gives about the same overall first gear ratio you'd be looking at with the TKO and the 3.08 rear gear. I find it annoying to get moving as the rpm is too low and if I don't rev the motor more than I'd like and slip the clutch the car shudders to a start. I realize you'll have far more power than my stock small block, but I think if I was you I wouldn't like that overall first gear ratio.
Le Mans Master
Joined: Oct 2007
Posts: 7,456
Likes: 977
From: RI, Now Franklin/Nashville TN
Exactly.
That's why I'm looking at the TKO 600 with the .82 and 3.08 rear gearing.
At 65 mph in 4th I'll be at 2470 rpm and in 5th 2025 rpm.
Around town will be tame and roll on at 65+ speeds will be hot with the operating range of my cam at 2000-6000 rpm.
The 496 at 600+ ft lbs torque should still be plenty of fun around town even with the 3.08's.
With a 3.36 I'll only be at 2694 rpm in 4th at 65 mph and 2209 rpm in 5th at 65 mph.
That's why I'm looking at the TKO 600 with the .82 and 3.08 rear gearing.
At 65 mph in 4th I'll be at 2470 rpm and in 5th 2025 rpm.
Around town will be tame and roll on at 65+ speeds will be hot with the operating range of my cam at 2000-6000 rpm.
The 496 at 600+ ft lbs torque should still be plenty of fun around town even with the 3.08's.
With a 3.36 I'll only be at 2694 rpm in 4th at 65 mph and 2209 rpm in 5th at 65 mph.
With my 355 L-82 with a cam operating range of 1,500-5,600 RPM, the motor can run all day long at 1,500 RPM on the highway at 80 MPH and it would be perfectly happy. My 10C6Z06 cruises at 80 MPH at 1,750 MPH....which is perfect and gets 28 MPG doing it. Ill take 1,800-1,900 RPM @ 80 MPH all day long with the 355...That is what OD is for......
Melting Slicks
Joined: Dec 2009
Posts: 3,233
Likes: 657
From: Thunder Bay
Many years ago I built an S-10 with a small block, 3.70 rear gears, and 3.27 first gear. Great truck, but first gear just didn't work. The truck originally had a 2.8 V6 - hence the deep first gear. Pretty much useless with a V8. Better off starting out in second gear in street driving. 12:1 is way too deep a gear ratio. My '79 has the TKO 600 with 2.87 first gear and 3.55 rear end for a final drive ration of 10.19:1 which is just about perfect.
Le Mans Master
Joined: Dec 2009
Posts: 6,397
Likes: 649
From: Saskatoon Saskatchewan
Many years ago I built an S-10 with a small block, 3.70 rear gears, and 3.27 first gear. Great truck, but first gear just didn't work. The truck originally had a 2.8 V6 - hence the deep first gear. Pretty much useless with a V8. Better off starting out in second gear in street driving. 12:1 is way too deep a gear ratio. My '79 has the TKO 600 with 2.87 first gear and 3.55 rear end for a final drive ration of 10.19:1 which is just about perfect.
Drifting
Joined: Mar 2011
Posts: 1,347
Likes: 121
From: Kernersville NC
I can't completely agree with this. Yes it is a drop from 4th to 5th. However the OD is not meant to be an acceleration gear. It is a cruising gear. Besides that, with 3.55 gears it will pull to 120+ in 4th at 5400rpm. You really need a drop after that. If you are racing the .82 would be better.
Le Mans Master
Joined: Oct 2007
Posts: 7,456
Likes: 977
From: RI, Now Franklin/Nashville TN
I can't completely agree with this. Yes it is a drop from 4th to 5th. However the OD is not meant to be an acceleration gear. It is a cruising gear. Besides that, with 3.55 gears it will pull to 120+ in 4th at 5400rpm. You really need a drop after that. If you are racing the .82 would be better.