If you have a spread bore carb with an electric choke, it will work fine. If you are running headers, that electric choke might work better, the old stove pipe set up didn't work as well if the heat crossover in the intake didn't function correctly. Just make sure there is a cover over where the stove pipe would have bolted on. By the time the spread bore carbs came around, I believe the stove location was already closed, but with the earlier 4 bbl intakes, they had an open hole into the exhaust crossover which needed to be closed. 20 years ago I could have told you which intakes had what, but that water has will left the area. If that intake has an EGR valve, make sure it and the gasket under it doesn't leak, the EGR does not have to function, but the hole in the intake has to be sealed..

The 340 and the 360 4bbl intakes do have larger intake port then a 318 has. For street use, the differences in the intake port size won't be noticeable, and the intakes seal just fine. Do not worry about the intake port sizes unless you are going drag racing. That 4bbl and opening up the exhaust from the restrictive single exhaust (just adding dual exhaust with the stock 318 exhaust manifolds) will make a noticeable difference in the seat of the pants. I ran a 340/360 intake on 318 heads with a huge cam on the streets without issue for 5 years. When we put that motor in our dirt track car, the 346/360 heads made a difference that was not noticed on the streets. Higher RPM makes the difference, if you plan on turning that 318 much past 4800 RPM, consider the 340/360 ( or late magnum) heads.

The spread bore intake first showed up on a 340 in late 71. It had the Thermoquad, and the open casting stove pipe choke. By 73, the 340/360 intakes had the closed stove pipe choke with an electric assist (that pulled the choke open pretty fast in cold climates). As far as I remember the Thermoquad never had a full on electric choke. When the Quadrajet replaced the Thermoquad in around 1983 the Quadrajet had the full on electric choke, but the intake also got the EGR valve.