How to tell difference from reg to comm chassis?

[StepinNJ]

I am looking at what I believe is a 1970 K30 pickup truck. Owner says it may not have originally been a pick up truck. Is there a way to tell if it was once a commercial chassis and then converted to a pick up body? It has a duallie rear that doesn't stick out past the wheel wells. The bed is 8 foot and there is no gap between the bed and cab. Something in the vin maybe?

[71K20chevy]

To my knowledge there was never a dually pickup from the factory.

[StepinNJ]

Originally Posted by 71K20chevy

To my knowledge there was never a dually pickup from the factory.

You're right. I believe the rear came from a 68 wrecker. That being said, if someone converted a commercial chassis to a pick up, how would I know? Did comm chassis have the same wheel base as 8 foot pickups?

[SS Tim]

There are a couple of problems here.

First there are no known factory K30 trucks built during the 67-72 model years.

Chassis and cab trucks were available in C10-90 & K10-20 models.

Dual rear wheels were offered on C20 and up chassis and cab trucks but not as a pickup truck, again 67-72.

The factory dual wheel conversion option (RPO RO5) was a narrow track axle that will almost tuck under a box but is also narrow between the wheels so a stock bed must be modified to fit.

Pickup box brackets were offered as an option on some chassis and cab trucks.

Pickup box brackets were riveted to the frame.

The easiest way to tell a factory chassis and cab from a pickup is the model number on the SPID or serial number (VIN) plate. if it has not be changed.

A C30 pickup (fleetside or stepside) would have a 133" wheelbase and a 8 1/2 or 9' bed.

The frame rails for both the C30 133" chassis and cab and the pickups are basically the same.

By all counts this would seem to be a "built" truck from the information given. Given the apparent 127" wheelbase it might be a K20 rebadged as a 30 which does happen through an emblem or cab swap.

[StepinNJ]

No emblems, just assumed K30 because of rear. Will check the vin later.

[special-K]

No such thing as a commercial chassis. They'll all the same in any given wheelbase or configuration. A 157" WB cab & chassis dual rear model could be an RV. What exactly are you wondering? If it's got an 8' bed then it was a 3/4t or a 1/2t originally. Just check the VIN on the frame to know exactly what it started life as. I'm sure it wasn't a factory K/30 because they didn't make those. The "only" HO52 dual rear made was the narrow cab & chassis type.

[StepinNJ]

Just found a vin decoder on this site.

KE240Txxxxxx

4X4 V8 3/4 ton pick up. Owner thought it may have been something before and then converted to a pickup. I guess someone just put a narrow duallie rear in at some point.

[SS Tim]

Are you sure it is a dual wheel rear end. See if you can find an axle code.

[CrewCab59]

You might have a std rear axle with dual rear wheels add if so how close is the wheel/ tires to the spring?

Cab Chassis have narrow rear axle.

The true dual axle 73 and up are wide 14bolt and 70hd which would not fit under a std 8ft bed being that 75" WMS

[StepinNJ]

Don't have the truck yet. Getting it next week. The wheel tubs were widened to fit the extra wheels. I will look for an axle number and bolt count.

[special-K]

Are the wheelhouses widened? Dual rears don't have 4' between them