"My '80 320i motor is showing its age and I was told that a
"big six" motor would bolt to my 5sp. I orig bought this cars for daily driver/2002 upgrade parts but have become
attached to it...

Having other projects, I just want to get a good condition used motor (carbed if possible, I'm fuel injection ignorant) and plunk it in.

A body shop friend has agreed to a paint job to cancel
a debt, and I just did the brakes. Hoping to get larger
motor for under cost of stock rebuild.

I don't know much about 6cyl cars and am wondering if this
upgrade is possible? If yes, what make of 3, 5 series motor
do I seek?

Any info would appreciated.

Thanks,
Rick G
80 320i ex 02 donor, daily ride
73 02tii Zombiemobile (dead, to rise again)"

The "bg six" does fit , but only without the engine driven fan .
So keep that in mind when planning the cooling upgrades.

You might be hard pressed to find a carbeb bix six , here in the states at least.
I think you should go for anything with a "35" at the end of the model designation.
This would yield you a nice 3.5 liter.

Why not throw an e30 M3 motor in there. It's nearly the horsepower of a 3.5 only with less weight. Less weight=more acceleration, better handling, quicker braking and better mpg. I've seen a decent number of 2002 with this engine swap, and I believe that there's actually a kit for it. Just a thought.