Hello, I recently picked up an 85 F250 with the 6.9, and after doing a little searching my serial number is apparently one of the last produced before they were reinforced (mine is 173656, from what I've read it was about 173800 when the blocks were reinforced). This truck is relatively low mileage (about 90k original) and I was planning on, over time, adding a few performance upgrades to try and eke out some more power and MPGs. Nothing crazy, but maybe a banks turbo, new exhaust, that sort of thing. Mostly used as a driver and to pull light loads. I know to avoid the block heater and will be putting an in line radiator heater in soon. My question is, is this reasonable to do with an older style block or should I focus on other areas of the rebuild and then drop a different motor in there when I get to it? I plan on doing this slow over a year or two, so budget isn't a huge concern either way. Thanks in advance!