Upgrading from original 2 barrel on 287

Getting a little more punch is going to be tough. I'd go with a factory 4V intake providing you can find one, and a 500-600 cfm carb. The Edelbrock 500 cfm (#1403, with electric choke) would probably be your best bet. The smaller barrels will mean a bit better throttle response.

You can stick with a bit larger 2V and would probably get close to the same results, but the 4V would be more economical as it would run on half the carb half the time. Would be a bit less cash to stick with a 2V as you don't have to change the intake. An Autolite 2100 with a 1.21, 1.23 or 1.33 barrel (venturi) size would be good (300, 351, 424 cfm). 

Note that cfm rating methods are different for 2V and 4V carbs! To convert a two-barrel rating into a comparable four-barrel rating, divide the two-barrel rating by 1.414. To convert the four-barrel rating to a comparable two-barrel rating, multiply the four-barrel rating by 1.414. So a 350 cfm 2V is comparable to a 248 cfm 4V. A 500 cfm 4V would compare to a 707 cfm 2V.  The 500/4V works okay because you only run on half the cfm (comparable to a 350 cfm 2V) capacity most of the time, and the secondaries (other half) only opens AS NEEDED. An otherwise stock 287 probably wouldn't pull the secondaries more than half way open, so you'd only be pulling no more than about 500 cfm wide open. You don't need but about 350 cfm (the stock carb is about 250 cfm).

Just remember, the only way  to get more "get up and go" is to burn more fuel!! The smaller the barrels the better throttle response (feel at the gas pedal) because the air/fuel mixture is moving faster in the intake. Get the big 424 cfm 2V (or a 500 cfm Holley 2300... there is a 350 cfm version that would work well) and floor it and the engine will likely bog. It wouldn't with the vacuum secondary 500 cfm 4V because only the two primary barrels would snap open -- the other two would gradually come in as engine speed (and vacuum) picked up.

If you open the choke flap and look down your carb you will see the two barrels.

Boris Badanov wrote: I got to disagree. 4412 Holleys are best used as desk top conversation pieces. They are NOT a street carb.

500cfm Circle track carb, I had one on my 290, it flat-spotted on acceleration and was awful on gas.  The switch to the 500cfm Edelbrock 1403 is like night and day.  Better throttle response and mileage, and tuned better out of the box than I could ever get that 4412.

That's why a 4V feels better, and a vacuum 4V is best (for a street car). Running on half the carb feels like a small carb, but the secondaries will open as far as the engine will use the added fuel, and no more. The 500 cfm 4V will work as good as the stock 2V at low speeds, and as I mentioned, probably won't open the secondaries more than half way at higher speed -- flowing around 350 cfm on that engine. But it would be better at low speeds (feel, power, and economy wise) than a 350 cfm 2V.

farna wrote: That's why a 4V feels better, and a vacuum 4V is best (for a street car). Running on half the carb feels like a small carb, but the secondaries will open as far as the engine will use the added fuel, and no more. The 500 cfm 4V will work as good as the stock 2V at low speeds, and as I mentioned, probably won't open the secondaries more than half way at higher speed -- flowing around 350 cfm on that engine. But it would be better at low speeds (feel, power, and economy wise) than a 350 cfm 2V.

Any modern v8 in the 5 liter class will pull a 500 Eddy (Carter) open by 3500 rpm.
That 287 would love a 600 or 500 Eddy.

Heck, my 1970 390 pulled two 625 Comp Series Carters open by 3500 rpm.
It was one helluva ride!

I would not put a Holley 4bbl on it.