Bought a rare LD4B for my 318 ( 1971 casting ) and a bunch of other parts / engine gaskets / copy of an edelbrock air gap / 650 dp carb / 5.9 magnum exhaust manifolds/ dual exhaust set up .............* My big Question is unfortunately the LD4B is massively ported to the 340/360 gaskets , i didnt know and the ex owner didnt know either, it was to put on my standard 318 heads, i wanted to do some test with the ldb4 and my carter 2bbl and my 650 holley dp , cam swap will be later , * How hard is it , To port 318 heads to a 340/360 gasket , never did such a thing , thanks guys