SRW K30 and K20 differences

[1977ChevGMCK2025Fan]

I am trying to figure if K20 and 30 shared the same frames, rear ends, and springs in the rear. I am guessing up front the difference was K30 got a Dana 60 and K20 a 44? Were the front springs different as well? Any other differences? Thanks,
Marvin
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[44th Miss Inf]

On the K30 rearend the shocks were moved to the inside of the frame, the drivers side was forward of the axle, and the springs were on 40.5” centerline instead of 42”

[1977ChevGMCK2025Fan]

Originally Posted by 44th Miss Inf

On the K30 rearend the shocks were moved to the inside of the frame, the drivers side was forward of the axle, and the springs were on 40.5” centerline instead of 42”

Thanks!
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[1977ChevGMCK2025Fan]

Originally Posted by 44th Miss Inf

On the K30 rearend the shocks were moved to the inside of the frame, the drivers side was forward of the axle, and the springs were on 40.5” centerline instead of 42”

Thanks!
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[THI]

K30 frame is taller than a K20. Front springs mount the same, rear springs have different front and rear mounts, springs themselves MAY be different, some K20 came with 52" springs, others with 56" springs - K30 rear springs are 56"

[SunSoaked]

K20 generally had SF and the K30 had FF. I have a K30 in my K20. Had to relocate spring perches and shock mounts.

[MJN]

Originally Posted by SunSoaked

K20 generally had SF and the K30 had FF. I have a K30 in my K20. Had to relocate spring perches and shock mounts.

This is somewhat incorrect. K20's had 14 bolt full floater rear axles as standard equipment, the 9.5" semi-float 14 bolt didn't come around until '81. Yes- K20's from 1981 and after had the semi float but they could also have come equipped with the full floater depending on the GVWR.
K30 frames are 8" tall behind the cab vs 6" tall on a K20
K30 rear shocks are located inside the frame vs. outside the frame on a K20
Lots of rear spring info in these info packets outlining the different spring packs between the two;
https://www.gmheritagecenter.com/doc...olet-Truck.pdf

[1977ChevGMCK2025Fan]

Originally Posted by MJN

This is somewhat incorrect. K20's had 14 bolt full floater rear axles as standard equipment, the 9.5" semi-float 14 bolt didn't come around until '81. Yes- K20's from 1981 and after had the semi float but they could also have come equipped with the full floater depending on the GVWR.
K30 frames are 8" tall behind the cab vs 6" tall on a K20
K30 rear shocks are located inside the frame vs. outside the frame on a K20
Lots of rear spring info in these info packets outlining the different spring packs between the two;
https://www.gmheritagecenter.com/doc...olet-Truck.pdf

Thank you!
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