1965 Barracuda 273 rebuild...intake code?

Thanks for your feedback and info! The previous owner evidently installed a 1967 273 block for unknown reasons, but stock heads for the '65 273. We discovered the block was bored .40 over with regular pistons, heads were milled, and a new valve job. The crank had been turned to .10/.10 and a hydraulic cam set up installed which we replaced with a more aggressive cam set up. Compression is about 9.2/1. We put all new cam kit, rings, all bearings, hi volume water pump and oil pump Just wish I had a sure grip rear diff but for now have to settle for the stock 7 1/4 open differential. Installed new ball/trunnion and u-joint, checked over the A-833 4 speed and all seemed to be good, installed new clutch kit.
Still wondering about maybe changing heads, what do you think. Keeping stock exhaust manifolds cause I can't seem to find a set that fits the 4-speed set up without having to modify parts.