Vacume Advance

I'm kinda' new to this so please speak slowly. I'm rebuilding my 1800 from my 79 MGB. Adding a little more reliability and a little more umph! When I got the car, most all of the emissions components had been removed. Thats fine by me. But I'm interested in a Mallory distributor. It has no 'vacume advance' like the stock does. Do I need to use this? I'm still going to use my SU's if I can.
The second part of my question is the two absorption cannisters in front of the glove box. What do they do and can I ditch them. I was told that they were for emissions.
Thanks for anyones help!

I believe the Mallory's have the mechanical advanced recurved to compensate for the lack of a vac advance.
I would keep the absorbsion canisters. Without them, you will have to find another way of venting the tank and probably would end up with a strong gas smell building up in the car.

Actually, Mallory does make a dual-point distributor that will fit the MGB and has a vacumn advance. The one that Moss sells does not.

I asked at a local autoparts store that sells Mallory products. He looked it up in their catalog and there were two models, one with and one without vacumn advance. The one with was more expensive, but I think it was still less than the one Moss sells.

I think that Moss only sells the one without vacumn advance, because it is often installed with Weber DCOE carbs, which I don't believe have a vacumn advance.

Also, there have been threads on this and other BBS's about the difference in advance mechanisms on MGBS. It seems that the later B's, used manifold vacumn, rather than carb vacumn. The two are different and the vacumn advance unit needs to work with the appropriate vacumn source. It is probably just simpler to sell the non-vacumn advance version. As Thomas pointed out, it has fully adjustable mechanical advance that can give as much or more total advance as the stock dizzy, and thats all that matters.

Putting a mallory distributor on a stock engine is a waste of money. The only reason to use a dual point dist. is for a higher compression engine with an increased CFM. It also is benefitual when turning in excess of 7K RPM's due to points bounce of the stock dist. You can get stock dist. w/o the vaccum advance and a wider advance curve that will handel 7K RPM for a whole lot less that a Mallory.

The only dual point distributors that I have come on early hemis (54 Dodge Red Ram). They don't turn 7k rpm and I don't think the 2 barrel carb has a lot of CFM.
The MOPAR thinking for dual points is that the second spark burns the leftovers in the firing chamber, thereby being more efficient and scarfing all power possible. With only 241 cid, they need it.
But, maybe it's not benefical with a B, I don't know.

Don't worry about the vacume advance, it's only on the stock distributor for part throttle performance. I am currently running my B GT without the vac. adv. hooked up. I have noticed a small drop in power at part throttle, but the top end is slightly improved.
As for the cannisters i would leave them alone.

Matt, keep the cannisters, but ALL you guys get a red check mark on vacume. It's vacuum.

OK, I give up Tom. Where can I locate stock dist w/o vacuum advance for less money than the Mallory??

I get them from my local parts store. They are rebuilt. I can't remember the part #,and I want be back to my shop till the first of Jan. Check with http://bhive.tierranet.com/index.html they may can get one for you. Its a Lucas.