sooo slow

[bettabruce]

my 75 k5 is so slow. it has stock tires, a probably bad carb,

and i don't know of any major modifications.

The previous owner changed the gear ratio (the speedometer reads

around 15mph slower than speed) i don't know much about my truck's

workings. I had a 76 that was so much more powerful.

Anyway, any ideas? I just replaced plugs, wires, and rotor cap, but

when the pedal is on the floor I can barely creep up to 70 mph.

Thanks in advance

 

[dune jump]

what are the specs? K5s in stock form aren't usually race cars, but they have endless potential.

Give us something else to work with

 

[75GmcJimmy4x4]

my 75 k5 is so slow. it has stock tires, a probably bad carb,

and i don't know of any major modifications.

The previous owner changed the gear ratio (the speedometer reads

around 15mph slower than speed) i don't know much about my truck's

workings. I had a 76 that was so much more powerful.

Anyway, any ideas? I just replaced plugs, wires, and rotor cap, but

when the pedal is on the floor I can barely creep up to 70 mph.

Thanks in advance

yeah we need more info ..... but is it quick at takeoff but slow in top speed or just a slug all the time ??? does it smoke black and stink like fuel

 

[k20]

run a compression check, the 75 may have an original engine whereas the 76 may have had a rebuild more recently than 35years ago.

 

[bettabruce]

i'm going to run a compression check this week

 

[k20]

something else I didnt think about, if the PO changed the gear ratio and now the speedo is reading slow, then he swapped in a higher gear set which will make it slow off the line, turn less rpm at speed, and generally be sluggish. If it is 15mph off that sounds like a rather substantial drop in gear (or larger tires [you dont mention tire size]) which would make it seem slow.