[Elwenil]

If you are going to spend the money for an upgrade, go for the Magnum 360.  No point in spending almost the exact same money for less power.

 

[Elwenil]

318/360 is the same transmission.  A 360 will require different converter balance, but this can be had with a B&M flexplate or a weld-on weight kit.

 

[Elwenil]

Yes, the balance weight for the LA 360 and the Magnum 360 is different.  LA 318 and Magnum 318 are the same, neutral balance.

 

[Elwenil]

The only thing a Cummins swap is cheaper than is a blown big block.

 

[Elwenil]

I didn't say it wasn't a good swap, nor did I say it wasn't efficient, but it is very expensive to obtain a 6BT these days unless you get very lucky.  Even then, if you end up with something other than a 1st gen, gathering all the needed parts to do a good swap will nickle and dime you to death.