340 Hydraulic Roller Available?

Well here's my two cents hydraulic roller will work fine in the block as long as you don't put too much Cam in it as other members have already said the lifters will come out of the Moors if you have too much lift exposing the oil band on the lifter also you have push rod clearance issues with X or J heads pretty much anything that didn't come with a roller say a 302 head would work fine but it has a small port and small intake runner a better choice would be a Magnum or a magnum replacement head I know that sacrilege but that it's the way it is I hope this helps you