Crazy idea for 318

I think what everyone is forgetting is:

a 318 IS a 340...with a 3.91" bore....all else the same, block dimensions.
Same 3.31 Stroke....same oiling passages....it would be seriously complicated to achieve your goal with the stock, bore of 3.91"...or .030, or even .060" oversized.

If you were to Bore the 318 Block to 4.04"....and get a set of 340
11:1 pistons, you would have yourself a 340....I dont know why so many people are afraid to bore a 318 .130" of an inch...its nothing really....race or street....if your concerned...fill the lower portion with block filler...race cars only need to run 5 minutes or shortly longer.

At that point, You would need a Double Roller Chain, and tensioner, A new oil pump, windage tray, ARP Head Studs, Cometic Head Gaskets, a set of fully ported RHS X Heads...(although some Aluminum Head Castings could save you about 40lbs), 2.02/1.60 valves, .600" lift springs, 234 @ .050, .580" lift, 110* center cam, Mopar M1 Single Plane equally gasket matched and ported, and a Holley 850DP.... fed by a 8AN, 7 psi regulated fuel system with a return line.

I would use a "loose" 9" convertor that would flash around 4000rpm, and less gear...like 4.10's or 3.91's....and a 10" slick.

I could see low low 11's out of this setup....properly dialed in.