I have 1976 280Z w/ Rebello 3L L28 with Jenvey ITB's. Makes 325 hp.  Took car to to first track day since engine install Monday.  When tank gets to about 1/2 full, fuel sloshes away from fuel pick up in bottom tank causing engine to stumble. I'm using stock tank with original pickup and returns going to Airtex high flow fuel pump mounted on modified stock fuel pump bracket and stock fuel lines to fuel filter.  Has anyone else had similar problem or solution?  This is primarily a street driven car with occasional track days and autocross events.  I really don't want to chop up and install fuel cell.

1 hour ago, ScooterZ76 said:

I have 1976 280Z w/ Rebello 3L L28 with Jenvey ITB's. Makes 325 hp.  Took car to to first track day since engine install Monday.  When tank gets to about 1/2 full, fuel sloshes away from fuel pick up in bottom tank causing engine to stumble. I'm using stock tank with original pickup and returns going to Airtex high flow fuel pump mounted on modified stock fuel pump bracket and stock fuel lines to fuel filter.  Has anyone else had similar problem or solution?  This is primarily a street driven car with occasional track days and autocross events.  I really don't want to chop up and install fuel cell.

The 76 tank is pretty rare but if it were me I would modify the tank or source a second one and modify it. You could build trap doors like racing oil pans have to prevent fuel from sloshing away from the pick up or make a lower sump area. I know there is another way to accomplish this too. I think you pump into an intermediate container then pump from that to the engine but I don't know exactly how that's plumbed.

Are tanks from 240, 260 and 280 interchangeable?  Might make it easier to source a tank.

No

https://www.google.com/search?q=240z+280z+gas+tanks&client=ms-android-americamovil-us-revc&prmd=sivn&source=lnms&tbm=isch&sa=X&ved=2ahUKEwjp8OGquZ7iAhXJct8KHcTIB7cQ_AUoAnoECA0QAg&biw=320&bih=449

Tanks Inc and Holley sell great in-tank pump solutions. There are others, do a bit of searching.

I like one of the Holley setups as it comes with their Hydromat product that acts like the world's best fuel sponge in the bottom of the tank. Look up the Holley 12-130 

I got a Holley 12-130 Fuel Mat pump.  It has a vent line i the pump.  Can  I get rid of the vent lines on the back or the tank going to the canister, and the canister for that matter, in the passenger side quarter panel? They make it a a real PIA to install and remove tank.  If so, should I put roll-over valve in new vent line between tank and steel vent line going to front of car?