Question on Diffusion Chamber in Beseler 45

I found a nice deal on the Besler 45 diffusion enlarger.
It has the 4x5 diffusion chamber.
Today I print 120 6x7 film.
I have the correct enlarger lense for 6x7 and the 6x7 negative carrier is no problem for it.

If I buy this enlarger do I have to also find the Besler 45 6x7 diffusion chamber?
Wouldn't the 4x5 diffusion chamber also work with 6x7 negs?

Using a diffusion chamber matched to the size of your negatives has two advantages:
1) you will maximize the amount of light going through the negative, which means your printing times will be minimized. That is obviously most important for large enlargements and dense negatives;
2) you will minimize the potential for extraneous flare - something that may not matter much for enlargers designed for professional use, but possibly more important for enlargers that aren't as carefully put together.
It is reasonably likely that your enlarger will perform very well with just a 4x5 diffusion chamber. My Omega D6 with an Ilford Multigrade 400 head certainly did - the 6x7 and 35mm diffusion chambers stayed in the drawer. But If I had seen the need to make lots of prints from 35mm, in a relatively short period of time, I would have happily swapped the diffusion chambers.

I use my 4x5 chamber for 6x6 and 35mm with no issues. Enjoy.

Matt King is correct, your print times are longer on the 35mm. But I live with it.

Now, I did usually print 35mm with a condenser enlarger and got high contrast. I wonder if the reduction with the diffuser is flare. But then I live with it for the loss of dust spots.