The 416 heads will work well for you if you fully port them first.
use a 1.94x 1.60 valve set in these heads. Don't be shy with the porting.
In stock form they are lame, like all the stock SBC heads. In fully home ported form they are actually pretty good.
if you are willing you can fill the exhaust egr ports in the center exhaust ports using old melted pistons
as a filling material.
This stops the cross talk between the center exhaust ports.
You can flat mill the heads to a 52cc chamber (to the edge of the 1.94 intake valve seat) to reaise the compression with a stock dished piston.
Or get some flat tops.
Get a 3500-4000 rpm stall converter. 9" -10" more is better.
More gear is better too. Don;t be shy with either.
A fully ported 416 head:
The XE284H-10 cam will work the best with the distributor locked out.
34 to 36deg Use a champion RV8C plug .035"
Pretty simple. Get some good valve springs so it can rev up. 110-120 seat 300-330 open. (.510" lift)
shim then as required.. ( deeper ex spring seats)
Drill and roll pin the rocker studs.
Use a thin felpro 1094 head gasket.
If you spend the time to port and prep these heads for your budget 350 it will work very well for you.
This is a pic of one of the many ported 305 head budget 350's I have done.
On a stock dished piston 350 a finished 52cc chamber and a .015" felpro gasket will get you a 10.50:1cr on
your budget 350. Just right for the XE284H-10 cam in your 350.
If you burp the wallet for a flat top piston finish the heads to 62cc. (10.50:1)
You can buy a compete summit 350 SBC rebuild kit with flat tops for $200.
Either way works and 10.50:1 is just right for this build. (92 octane)
On this one shown here all I did was re-hone and re-ring and bearing it, reusing the stock pistons. Ran very well.
no the carb is not too big. It is just right. Anything smaller will choke this motor.