I'll throw in here as a guy thats built a couple mopar engines. the 318 and the 360 are almost identical engines. the 318 can be a 13 second motor in less that 2500.00 get a 4.00" stroker crank from mopar perfromance and have it gront to fit in your 318, and have the block clearanced...wham...you have a 390c.i. find yourself a good set of j or x heads, top it off with 750cfm carb and a single plane manifold and a good cam......and youre there. most good 390's are pushing between 350-450hp depending on the cam. if you can't run a soild 13 in an a-body with that.....there's something wrong.