Jeep frames/engines

I have always assumed that same year and model Jeeps were made with the same frames and then had different size engines put in them. As an example, the CJ5 I own came with a factory V8 304, so I assumed that frame is the same as a CJ5 that came with an inline 6.

A friend of mine is trying to convince me that the smaller engine jeeps had a lighter frame than the bigger engine Jeeps. We are talking same year and model. So he is saying my CJ5 frame with the 304 is beefier than the same year CJ5 that has the I6.

The reason that I ask is that I know there were some 4 cylinder scramblers made and if I happened to find one of those I would want to upgrade the engine.

Can anyone settle a bet? I got a 12 pack of Shiner riding on this to prove him wrong.


Definitley Certifiable
"Lighter" as in thinner gauge metal used to construct the frame?
Far as I know, all frames are the same outside of the front shock mounts pre 1981 and then the differences between CJ5, CJ7, and CJ8 for length and extra body mounts / crossmembers.

The only way frames get lighter around here is with rust ;)

Thanks for the help guys.

As 'Norm' says the two best kinds of beer in the world are 'free' and 'free light'.

I hadn't thought about the suspension being different, I guess it would be slightly heavier or lighter suspensions depending on 4,6 or 8 cylinders, or in the case of the CJ8's just 4 or 6?

My buddy put YJ leaf springs under his '77 CJ5 / 304. What do most of y'all upgrade your suspension with?


Legacy Registered User
SOA Member
There are a few differences for both frames of 5 and 7 for 1976 compared to the rest of the frames till the end of production in 83 and 86 but, as others have already told you, the frame is always the same in the area of the engine with the only difference of where the engine brackets are bolted.
And then for few 5s (still narrow track) and for the 7s and 8s the extensions for the shocks when the wide track axels were introduced. But besides these few differences the frame tickness has always been the same.