Why did 4x4s never get big blocks?

[davepl]

In our 67-72 series what kept GM from putting the 402 in it? Was it a fitment issue or a marketing decision (it's always the latter, but was it forced by the former?).

For that matter why was the 427 or 454 never offered, even in the big 30s?

[turp mcspray]

They moved the engine rearward in the 4x4, for oil pan to axle clearance. Without making a 2nd firewall stamping, and possibly creating more necessary changes, I'm guessing they just took the easy way out, by not offering a big block in a 4x4.

['68OrangeSunshine]

Another theory might be that they didn't want to warranty the drive train, with the massive torque of the BBC on 4x4 equipment.
They also didn't offer the 292 L6 [another torque monster] in the K/5.

[tcrist]

Neighbor put a 396 in a 72 4X4 with no firewall clearance issues at all. Not sure what he had to do the pan though, if anything.

['68OrangeSunshine]

Yeah, and I used to run a '67 K/10 Suburban with a 454. PO told me he got frustrated with trying to pull his boat up to the [AZ] White Mountains. When the original 283 couldn't cut it he put in a 350. When he thought the 350 was too slow he dropped in a 454.
I'd like to ressurect that truck, there were only like around 1600 1/2 ton 4x4 [K/10] Suburbans in 1967, kinda rare. But I can't afford to rebuild that BBC, when it only got 8 highway and 6 city miles. It would pass anything on the road but a gas station. And it only liked Premium.
The points distributor fit OK. When I swapped in an HEI, it got tight. Don't remember any oil pan issue.
The BBC would also beat the driveline into submission. I was replacing uni- joints every 6 months.

[Bob B.]

The story I was told is that it had to do with torque, the 396's would put too much stress on the transfer case and Dana 44 front axle. The 351 V-6 was not available in 4X4's either. The first year for the big block in a 4X4 was 1982, and then it was only available in the K-30 with the Dana 60 front axle. Ford was basically the same way, no 390's in 4X4's.

[Keith Seymore]

Torque multiplication through the transfer case in low range.

It doubles the torque and the axles are not up to the task.

K