Cruising Speed?

[Tripleblack51]

Question for you mid-year guys.
Mine is a 67 coupe with a 4spd and 3:70 rear end. It's a great running car, but I want to know how safe is it to cruise at 60mph+ for an extended period with that rear end?
Currently when I'm at 60MPH it's taching at 3K.
We enjoy going on cruises with other vettes (at least 1-2/month),
but I'm hesitant to take the mid-year as most of the other vettes are C5's.
Cruising speed is usually 65- 75 MPH with little bursts of "playtime".
Am I hangin' out with the "wrong crowd" or should I swap the 3:70 for a 3:08?

Your thoughts and help are appreciated.

 

[WayneC]

I doubt there's any problem with safety, maybe a tiny bit more wear & tear on the driveline, but if cruisin' is what you intend to be doing, I would think 3.08 (2500 rpm) or 3.36 (2725 rpm) would be better ratios.

 

[IH2LOSE]

I have 4:11's 60 mph = 3250 rpm's

Allthought it noisey (sidepipes) this is what came in the car when it was built. Again the rpms are up fuel economy is down but this is what the cars were meant to do.the guy who ordered your car or mine when new probabley picked it up and off he went with never a concern about if he was damaging his car.We are all spoiled with todays cars that zip along at 2100 rpms at 80 mph.I remember an old willies plow truck I had with 4:10's front and rear the truck was screaming but I would have no fear of driving any place with it.

I plan on driving to carlilse this year with my 1966 and plan on installing a set of 3:25's for the trip to make it more pleasureable and to keep up with the wife in the C5.If I dont get it done I will still drive the 1966 to carlillse with out fear!

Go for what you like.I love the PLANT YOU IN THE SEAT FEEL of the 4:11's but never go out on a long drive useally the furthest I have gone in this car is about 2 hours.If the majority of my driving was long drives I would of removed the 4:11's long ago.Again I would remove them for pleasure of dropping the rpms not the fear of hurting the car.

Thanks Larry

edit I have some note I have to look for from a different site I used to frequent about how the gears work with your transmition.Me jumping from a 4:11 to 3:25 would be like starting out in secound gear presentley to wich I am ok with May bee one of the fellow here has that chart for us to see

 

[67HEAVEN]

This CHART that I created may be some help. Based on these calculations, my decision was to install 3.08:1 gears and a Richmond 5-speed in my '67 big block.

Take note that the lower gears, especially 1st (using the Richmond) act like a Muncie with 4.56:1 gears in the rear, but in 5th you're cruisin' in style.

 

[Tripleblack51]

Thank you guys..
You are what makes this place great!
I appreciate your feedback.
Again, my concern was/is potential damage I could do to my '67 by running at 60+ mph for an extended period.

Larry, you hit the nail on the head...I am used to cruising in my '01 and not seeing the tach go over 2k on long trips.

Being new to the mid-year (two months) it feels like it is looking for another gear and I am wary of cruising on the expressway at more than 60-65mph for fear of damaging something.

Regards and keep

 

[JohnZ]

My original/unrestored '69 Z/28 came with the optional 4.10 gears, and it finally got to me (3800 at 70) two years ago, as we do more highway cruising than 1/4-miling these days. I swapped out the 4.10 for a 3.55, and that calmed it down to 3200 at 70, which feels more comfortable (I'd have gone lower numerically, but it has an M21 and I still have to drive it around town). Highway-speed caravans weren't much fun with my '57 either with the 3.70 gears, which was one of the reasons I sold it last summer; the '67 I replaced it with has the original 3.36, and it makes for a nice cruiser at freeway speeds.

 

[Tripleblack51]

Thanks John,
Beautiful car you've got there. I believe that I'm going to go with a 3:08 rear end.

BTW, how'd you like working with Zora?

Regards,

Pedro

 

[richscorvettes]

I wouldn't worry about doing damage to anything with the gears you are running especially with the type of use you have described. I agree though that it can take it toll on your ears if you plan on driving long distance. I had a 66 (with undercar "off-road" exhaust and a 427/390; 4-speed) that was a great highway cruiser. I am using a 3:36 in a 67 now (with side exhaust and 502; 5-speed Richmond) that also works well when cruising but it can be a bit more tiring on longer trips.

From a comfort standpoint, I guess it really depends on the type of driving you will mostly be doing and how comfortable you are with it.

Rich Lagasse

 

[Tripleblack51]

Thanks Rich,
My concern was not so much for my ears...I damaged them a long time ago by listening to loud rock music in the 60's and 70's.

I was worried about the toll on the car by running at 65-70 mph for extended period (1-2hrs)

By the way, I visited your webpage and you have a two beautiful cars and an incredible set-up!

Thanks for sharing those great pictures.

Regards,

Pedro

 

[JohnZ]

Thanks John,
Beautiful car you've got there. I believe that I'm going to go with a 3:08 rear end.

BTW, how'd you like working with Zora?

Regards,

Pedro

Zora was an inspiring and fascinating guy to work for; after reading the "Zora" biography, I understand much better now what really drove him. Never knew much about his previous background back in the 60's - he didn't talk much about it.