higher mph speedo?

[jveik]

do they make replacement speedometers for 73-87 chevy trucks that go higher than the 85 smallblock factory one or the 100 big block factory one? I want to see if i can get one that goes up to at least 150 or 160, so i know for sure i will always know how fast my top speed is. the motor will probably wrap out at about 140, so i want just a little cushion zone lol. anyways, if they do make this replacement, do they make it look like the original, right down to the orange needle and the font/size of the numbers? That would be sweet, but i guess if it doesnt exist, ill have to pay someone with a fast car to drive beside me and tell me how fast i got lol...

[MT-2500]

Originally Posted by jveik

do they make replacement speedometers for 73-87 chevy trucks that go higher than the 85 smallblock factory one or the 100 big block factory one? I want to see if i can get one that goes up to at least 150 or 160, so i know for sure i will always know how fast my top speed is. the motor will probably wrap out at about 140, so i want just a little cushion zone lol. anyways, if they do make this replacement, do they make it look like the original, right down to the orange needle and the font/size of the numbers? That would be sweet, but i guess if it doesnt exist, ill have to pay someone with a fast car to drive beside me and tell me how fast i got lol...

Your best bet would be to get a good tack/tachometer and just figure you speed from that.
And you can see what rpm your engine is running also.
Mt

[jveik]

well, im gonna get a 6k rpm tach and put it on the steering column, but the torque converter will never lock up, so i cant be exact, although it probably slips less at higher speeds im assuming. I bet if its doing 3k at 75, then it probably can go a little faster than 150 at 6k, due to the torque converter being closer to non-slipping, if ya see what im saying lol

[MT-2500]

Originally Posted by jveik

well, im gonna get a 6k rpm tach and put it on the steering column, but the torque converter will never lock up, so i cant be exact, although it probably slips less at higher speeds im assuming. I bet if its doing 3k at 75, then it probably can go a little faster than 150 at 6k, due to the torque converter being closer to non-slipping, if ya see what im saying lol

Well I sure hope you have all of the saftey equipment that is needed to run that high of speed and are only running it on a race track.
Have you ever saw a movie of a tire at 150-160 MPH or a roll over?
MT

[silicon212]

Let's just say that it's not pretty.

[jveik]

yeah, im just saying hypothetically here lol, theres no way im taking a truck to that speed when i spent 20 grand on parts for and thousands of hours doing the frame up restoration myself. that would be a real bummer lol...
my buddy had an 86 silverado with a 454 that was pretty well souped-up and he "claims" that at 140, the rear end would start to be lifted up by the air flowing underneath it and he would loose traction and not be able to go any faster. i think hes full of it though

[MT-2500]

Originally Posted by jveik

yeah, im just saying hypothetically here lol, theres no way im taking a truck to that speed when i spent 20 grand on parts for and thousands of hours doing the frame up restoration myself. that would be a real bummer lol...
my buddy had an 86 silverado with a 454 that was pretty well souped-up and he "claims" that at 140, the rear end would start to be lifted up by the air flowing underneath it and he would loose traction and not be able to go any faster. i think hes full of it though

I do not know about underneath air but the air coming around and over the cab could put a suction on the rear of bed.
At them speeds you need to consider everything.
Good luck
MT

[jveik]

yeah lol true dat

[Blue Bowtie]

I'd be more concerned about air under the vehicle at 140 and above, perhaps even less on a pickup with nothing to prevent sailing at higher air speeds. That's exactly what your "buddy" was describing. He's very lucky it didn't get sideways at that speed, or it would still be rolling. One little gust of breeze the wrong way and he would not have been able to tell you about it - ever.

Tires would not be an issue with Z ratings, since they can dissipate heat and not distort at those speeds. But I seriously doubt a mostly stock SBC could punch a hole in the wind large enough for a truck to drive through at 140 MPH unless is happened to be putting around 415HP or more to the ground.

Unless you go aftermarket custom, finding a speedo that will fit like stock and indicate over 120 MPH is going to be difficult.

[jveik]

yeah he said it must have started to swing out in the back just a little (im talking inches here) because when he slowed down a few miles an hour, the rear wheels caught and he almost lost it... this was all probably about 15 feet from the guard rail next to him on I80 in the middle of the night in Omaha Nebraska lol, they have cops just sitting there waiting for drunks, and even though he was sober, if he was clocked at whatever speed he was doing, he surely would still not be driving to this day lol...

by the way, im not running a stock sbc, its actually a 383 stroker which hopefully will have a little over 450 horse when done and surely a little over 500 lb/ft of torque... though i bet there will be about 25 percent loss to the rear wheels with the th400 and 2 driveshafts (carrier bearing longbox lol)