CK5
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100 mph speedos
- Thread starter 79k20350
- Start date
pauly383
Daddy383
Very common in the 70's , you really don't see the 85 mph until the 81 body style where nearly all the trucks had catylytic converters and all the fancy emmisions .
My '77 K20 had one, don't know if it would actually do 100mph, but it had one.
pauly383
Daddy383
Theoretically it could do 100mph , its the aerodynamics of a damn brick that stop ya 
My old 76 blazer had one, had it buried one night and according to a GPS was doing 122.
Theoretically it could do 100mph , its the aerodynamics of a damn brick that stop ya
I agree with the theoretical part. But when I got it the motor knocked like a SOB and wouldn't rev past 3k. Combine that with the slipping Th350, 4.56's and 31" tires, 100mph wasn't going to happen. I drove it almost every day exactly the way I got it (bad motor, slipping trans) for about two years. When I pulled the motor I sold it to a friend. He dropped it into his 91C1500, thing still runs today. Hardley makes enough power to get out of its own way. Has about 20psi of oil pressure at 2500rpm. We know it's too far gone to try and save the crank (I knew that when I owned it) so it's more of a game to see how long it will stay running. We haven't been nice to it either. That motor has done it's share of burnouts, in the K20 and the C1500.
pauly383
Daddy383
I could bury my 85 mph one downhill with a overdrive tranny , scary as hell in a big rollerskate
My '77 had a 100 mph speedo
Dude, what year did you end up in? 
pauly383
Daddy383
Scotts stuff is probably pretty trick , whereas our stuff is still in boxes in the garage waiting 
I keep staring at my block wishing I had sheetmetal and interior money so I can assemble it and go fast in my Chevelle .
I keep staring at my block wishing I had sheetmetal and interior money so I can assemble it and go fast in my Chevelle .
lectric80
3/4 ton status
I think it actually changed in 79 or so. My buddies 79 has the 85 as well as my 80 was originally equipped with the 85 MPH speedo. Of course the new Autometer goes higher than that, but I really don't want to see what it feels like driving this thing at any speed higher than 80. Nor do I want to watch the fuel gauge drop that fast.
79rustyk10
3/4 ton status
My old 79 k10 that rotted out from under me had the 85 MPH speedo, while the current 79 K10 has the 100 mph speedo, Im not sure I want to see it that far over though.
troutbum_mt
1/2 ton status
My 78 has a 100 and will do it. You gotta let the dogs bark once in a while with these new "cheap" gas prices. ;-)
I have one, it's out of a junkyard though and not the original. I have got mine to 100, then the tachometer registered 400 more rpm and I shut her down. Of course it took about a mile to achieve this speed.
i only have the 85 speedo it seems more accurate than my 100's. Before i swamped the 52's in i was crusing up to school at 3500 RPM the speedo was past the mark. For a short time i took the engine up to 4000 RPM but let off becasue i did not want to rev much higher. After putting 52's up front i have not had it over 75-80 yet, and i don't know if i will try that any time in the near future. If you want to do the math i was running 35's 4.10 gear and a 465 trans
