Longest stroke non-tall deck?

[Knarley Darley]

If you look close at your block it is already clearanced from the factory at the bottom of each cylinder where the rod gets close. If you use a "H" beam rod you can go 4.250 without any grinding at all, however it is right at the minimum clearances. What I do is smooth out the casting and deburr that area just to be safe. Also make sure the rod side clearance is not excessive or the rod will move far enough sideways to be out of the center of the relief and hit. I have not personally done a 3/8 stroke in a 454, but I think it could be easily done even in a gen 4 block. On a side note, if you plan on using a factory pan, the flat part of the pan will need to be clearanced with a Ford tool (medium sized hammer) in a few places because the rod bolts will hit it. I test fit the pans, rotate the engine by hand enough to leave a mark in the pan and then smack accordingly.