DavidNHarris88

MelWff

when brand new there was no reason they couldnt go on a 10 hour drive at 75 especially a 77 which probably has a low numerical rear gear. Regardless of the new parts you mentioned having the car thoroughly checked would be a good idea including, pressure test cooling system, condition of all hoses, upper, lower, heater, condition of all belts, inspection of steering components and suspension bushings and ball joints, condition of all u-joints both axle and half shaft. Check wheel bearing play front and rear. Check all tires including spare. Check transmission and rear fluid levels and add/replace as necessary. Check all brakes for wear and signs of leaks.

calwldlife

comfort level aside,
it could be about mph and engine rpm.
77 was after 55mph law i think?
where 55-60 mph would be @2000-2500
that gearing would be in the 3ks at 65-70mph.

now the debate comes in.
will the engine last? tolerate the heat?

maybe that is what was told you?

ThumpingLotus7

You can most certainly go on long-distance highway drives in your 77. I've done 500 a day on the highway in both my 71 and 80 Corvettes, the 80 is a 4 speed.

If you've never done distance in the car I would suggest tooling around town for a week or two staying within a tow radius, wait for those ready to break things to break, then set out without worry.

I do always carry a set of sockets an alternator belt a fuel filter and other miscellaneous tools, pliers duct tape etc. But, over 30,000 miles of driving I've yet to find a reason to use them.

The13Bats

What a crock, when new or if restored or well mantained c3s make good daily drivers on roads or highway,
I used all mine that way owned many, from 16 to 53

People who say no they dont either have non up to par c3s, are spoiled to their sedans creature comforts or are scared something will happen to the c3 while driving it...

gbvette62

The two main limiting factors are your gear ratio, and your ability to pay for gas.

Assuming you have standard P225/70R15 tires, which are approximately 27" in diameter, with a 3:70 rear and a 4 speed, you'll be turning about 3500 rpm at 75 mph. A 3:55 rear will reduce your rpm to about 3300 at 75, and a 3:08 will drop your rpm to about 2800.

Turning 2800 rpm all day long, isn't to bad, but 3500 is pushing it a little. If your cooling and oiling systems are in good operating condition, 3500 all day long is certainly doable. But, as someone who's had their fair share of 3:70 and 4:11 rears, I can tell you that those sustained rpm's, can be somewhat disconcerting. This is why all modern cars have overdrive transmissions, and why a lot of owners of older Corvettes and muscle cars, are converting over to overdrive.

The other issue is that at 3000 rpm, these old cars tend to use a fair amount of gas. You can figure your probably looking at 14 mpg, at a steady 75.

Metalhead140

OldCarBum

My 73 BB TH-400 with 3.36 rear gears runs at 3070 rpm @ 70 mph on the highway. The rpm is a little high for my liking for drives over 30 minutes, so I have a tendency to cruise in the slow lane at 60-65 on the highway of longer drives. Kind of embarrassing being America's sports car.

lvmyvt76

NO, it gives people a chance to look at your car as they pass you!
I drive my 76 at 70 all the time on Interstates, and have no problem, like to St Louis(4 hours, or Kc, 3.4 hours) with no problem. This a stock 76 motor and transmission. The worst part is the seats, as you get older, your other car's seats are more comfortable. IMO. No heating problems etc, car gets about 19MPH, unless I have a little fun goosing it a little.

69_Shark

Here is a thought,
My baby is a 69 and I too was concerned.

I have 373 rear end and ran very high rpms on the freeway.
Instead of worrying I simply swapped my th400 for a stage 2 2004R with od.

Problem solved! Locking torque converter and OD! Perfect!

Now I understand the th350 is better swapped with a 700R4. But really same diff!
Some folks even claim it is a better tranny! What ever.

Swap and end the concern AND get better mpg AND get lower rpms! Win Win Win!

Just saying!


Scott

Ps all this from a guy now stuffing an LS7 and 4l75e into the 69!
Heh heh! Swap? Me? Never? Oh how i’ve Changed!

mrichi

I put a TKO500 in my 79 Vette , is the best mod iv'e done makes the car so relaxed on the highway

bschuus

I take my 80 automatic once a year on a 4 day weekend and put a 1,000 miles on it and it seems to get more comfortable as the miles pass. I’ll try to keep up with the others in their higher end cars with my rpm’s screaming at 3500 doing 65 to 70 mph. At times I’ll let them go and give the old girl a rest but I look cool going slower. Lol

My advice is go for it!

PainfullySlow

Got a 6spd going in mine, and I expect to take lots of long trips =)

builtwright

I drove my 77 from MA to Indiana and back in a weekend during a heatwave. My tach wasn't reading correctly then, almost double what it was actually. That was a little scary as it looked like I was redlining. I was getting 14.4 MPG. New 350/290 crate motor with new 3:36 diff. I put new tach board in since.

rcread

My wife and I take our ‘71 4-speed convertible from Seattle down to Napa, about 800 miles each way. Speeds are usually around 80 mpg. I got 20 mpg on a couple of tanks, with a 420 hp roller cam build I did on a 350.

OldCarBum

As part of my body off resto/mod, I'll be swapping the TH-400 out for a close ratio TKO-600 with 3.08 gears which should keep my 496 happy at 2200 rpm @ 70 mph.

DavidNHarris88

I just put a 350/290 crate engine in mine as well. I’ve got about 200 miles on it, still breaking it in

DavidNHarris88

Do you guys roll with spare tires??

Vibguy

I can't add to the C3 experience (yet) but I think it is all relative. When I take long trips in a 62 TR4 I look at the guys on motorcycles and think, man, what a luxury ride I am in.

TimAT

I haven't had my 69 really anywhere out of town, but right now it has 4.11 gears. Not a great thing for long highway drives for me. There are a couple other members here that has driven all over- like 6000 miles at a crack.