'77 3/4 ton Suburban goes 140 mph. Is this normal?

[OSUCowboy27]

I have a 1977 Chevy 3/4 ton Camper Special Suburban. It has a stock 350 with 350 turbo-hydramatic trans, 4.10 rear and dual exhaust. It goes 140 mph. Is this normal? It has a lot of drag and about 165 hp. How does it go so fast. There isn't any smog controls and runs on leaded gas.

[sniper4x4]

Are you sure there isn't a tow rope connected to a Nascar vehicle ?

[OSUCowboy27]

It is completely Stock except for the duals. Maybe it has more than 165 hp or I am going higher than 5000 rpm.

[sniper4x4]

you lost me on that reply.

[salty87]

kilometers?

[Pamsdad]

Maybe wrong gear in trans for the speedo.

It takes a ton of horsepower to get a vehicle with that much weight and aerodynamic ability of a 'Brick Wall' to go that fast.

Somethings not right...

[OSUCowboy27]

The suburban's speedo only goes up to 100 but when brought up to speed it will do a mile in 25 seconds which is a little more than 140 mph.

[TweakedGM]

get a friend in a car or truck get them to do 60mph and see what yours is at. If it is out you have the wrong tires, speedo gear, rear end., speedometer is gooffy or you could be running kilometers.

[sniper4x4]

Another more accurate option is to use a GPS to tell you the actual MPH. I cannot believe that a STOCK '77 Burb goes that fast impossible

[TweakedGM]

I think the only way is to down a steap hill with the pedal through the floor. then a steep hill to climb slow down.

[intel.inc]

To tell you the truth I just read everything that you guys have posted and don't you think that if it was really doing 140 that his 100 mph odom would of snapped the cable by now? I think so because I snapped my odom in my el camino before. And in my el camino it only read up to 80 or 88. And I had to be pushin that thing like 110 -120 on the freeway and it finally snapped.

[OSUCowboy27]

Originally Posted by intel.inc

To tell you the truth I just read everything that you guys have posted and don't you think that if it was really doing 140 that his 100 mph odom would of snapped the cable by now? I think so because I snapped my odom in my el camino before. And in my el camino it only read up to 80 or 88. And I had to be pushin that thing like 110 -120 on the freeway and it finally snapped.

The speedo wraps back around to zero, there is no peg to stop it. But it does not matter what the speedo says, the suburban does a mile (section line to section line) in 25 seconds which is more than 140 mph. The road is flat so it actually goes 140 mph. The trailering special 3/4 ton model must have more power than stock. It has oil and trans cooler and extra large radiator. The rear is 4.10 and maybe the 4 barrel carb is larger than normal. I do have slightly taller tires which would help with the 4.10 rear but has very little difference on speedo and odometer.

[Fedexjetmx]

How often do you guys get to OKC, because you need to get the
Guinness book of world records out to see this, because with a 4.10 rear end you’d probably be turning about 8000 rpm and that stock 350 can’t handle 8000rpm, plus that thing is so un-aerodynamic it would probably take a minimum of 600HP to get an old 77 ¾ to 140

[OSUCowboy27]

I bet if I supercharged it and put a 3.73 rear and a TH-700R4 trans. in it I could get it up to 200 mph.