"Selecting a Good Block"
When buying a flathead from a private party, there are a few things to be leery of long before you put a mike in the bore or get it Magna-Fluxed. An engine that is still in a car that has obviously been sitting out behind the barn for a long time should be regarded as one with a strong possibility of ongoing internal corrosion. The engine can very easily be a victim of rust. Water left sitting in the jackets can "thin out" the crankcase between the exhaust ports and the oil pan line.
Another telltale sign that might select out a contender even before a detailed inspection is an engine that has had the spark plugs removed, or the intake manifold obviously left off for quite some time. It is almost a certainty that condensation has added its evil effects to the water that probably remained in the jackets for a long time.
The ultimate decision as to whether you should purchase this flathead depends solely upon a careful and meticulous visual inspection, a measurement of the bore, and most importantly, a first-class professional Magna-Flux.
Now that you have done your homework, it is tome for the machine work! The time verses gain in porting and relieving the block can be disputed for ever. I have found for good running and dependable motors, forget the port and relieving - if you are going to build a full racing motor then go for it. The gain in a street motor would not be worth the price of the maching.
"Boring The Block"
First I would find an experienced shop that is familiar with the V8 Ford Flathead. Flathead blocks are known for "coreshift", which means that some times the wall thickness of the cylinders and other parts of the block may differ, so tred lightly. First, you should deck the block to insure of a good contact of the gasket to the block and head. Here again I say go lightly. Pick what you think is the worse side and mill at first maybe .005 to .007 to where you get at least an 80% clean up. Don't go too far! Then take the same off the other side. I like to go for the minimum over size on the bore. Check the ware in "all" the cylinders to find the largest one. Now here again, I am going for a dood, dependable flat motor. If .030 will clean the bore, then that is the magic number. Blocks should be checked for line bore of the crankshaft. Very seldom will it be neccessary to have the block line bored.
"Stay Tuned" More to Come!