Any thoughts on the anti-backfire valve?

Is it necessary? What problems would it cause to disconnect it? What problems arise from a mal-functioning ABV? Would it be worth putting a new one on?

All of the parts are getting tired, I am not sure which items are going to make my 77 run smooth thru idle to freeway.

is that the bronzy looking large hex nut on the carby with a wire attached? if it's that then the bum way of dealing with it if you don't have it is or it's not working is to stall the car when you shut it off. Can't say it does you bearings any good though

If you remove the anti-backfire valve, the risk is getting a backfire, and in worst case an engine fire. The anti-backfire valve is part of the air pump system, so you would have to remove it as a system and not the valve alone.

My 77 GFU "special carb, plugs, electronic ignition, Cat converter. Doesn't have an air pump. It has an air pulse from on top of the thermo to the side of air cleaner.

When I had a " stock" carb I just pulled the plunger out. I personally never had any sort of problem.

Your call.

Quote:
Yes, the Nissan A.I.S. system operates similar to the air pump system except is uses harmonic pulses to inject the air.

Same caution applies.

Get rid of all your emission crap. You don't need it. I had a 77 B210 and I removed everything. All of it gone. Switch to a Weber carb. The car ran much better than it ever did. The only vaccum hose you will need is the one for your distributor.
Anyone need a B210 Factory tach? Have one for sale. These are tough to find.

Don't remove all the emission stuff.
* The PCV system is good for your engine, and except for racing regulations there is no good reason to remove it
* vacuum advance is good for performance (at least you have worse performance without it. You can certainly recurve it for even better results but 'worse' emissions)

The A.I.S. system looks like it won't cause any peformance penalty (unlike the air pump system). But you can remove it and the car will perform just as well as with it. The downside of removing it is higher emissions.

If you are green for the enviorment than the PCV valve can stay. Otherwise plug it and just go with a drag pipe like the olden days.
Oh, you will need to fab a plate on the intake to cover the hole where the EGR valve connected to.

I always kept my pcv, keeps from blowing out the valve cover gasket and making a mess. (",)