I know every one said 221 are junk but I can get two 41 long blocks real cheap. The question is can they be safely bored to the stock bore size of a 239 plus .030 as I have pistons this size and a set of stock bore 3.187. Any help will be appericated.
You want to bore a 221 block out to accept .030 oversize 239 pistons ? Are the compression heights the same on both pistons? That would be the dimension from the wrist pin,to the top of the piston.
the stock bore & stroke on a 39-48 mercury block 3.187 x 3.750 which gives you a 239 cubic inch engine, starts out as the same block as your Ford, larger bore, done safely from the factory. you should buy a book & read about it. There are many very informative examples. Try Frank Oddo's "Ford Flathead V-8 Builders Handbook 1932-1953, specs, tech, examples, build up, theories, etc. You can learn a lot from that book. Cheater Carl
Has any one gone from the 3.060 stock bore to the 3.187 safely its only 127 difference. I need a answer without buying a book.
I have always heard it can be done, but have never done it myself. I think sonic checking the block to ensure enough meat is there would be in order for something like this though... Alternatively, you could try your question over on the Ford Barn Early V8 Forum - lots of good knowledge over there.
I'm running a 1937 21 stud, 221 CI engine that was bored out to 239CI and has a 49-53 crank, rods and pistons. It has a short track cam, .060 milled off the heads and some porting done in the intake and exhaust. It runs as cool as the stocker it replaced. I'm sure the 38-41 blocks had even more meat in them to safely bore them to the later specs.
There is no MORE risk in it then bore any other (later) block to oversize. It has been done with out any problems. They even bored 37/38 blocks to 3 3/16. May be you are lucky and got a truck block with factory relieve. I have a 81T block that is bored 3 5/16.
Most likely your 221 has a 239 bore that has been factory sleeved. Pop the heads and see what you got and go from there. The later 221's arent the same as the early, totally different casting. The biggest problem these days is the cost of bearings unless you go the 8BA crank & stuff route as already mentioned.
221 and 239 engines from this period are different castings but the 221s have enough meat to go 239 unless you have a shifted casting or serious rust. Most but not all of these have sleeves of about 080 over, so pushing out the sleeves will get you part way there. Sleeves leave a step at the top, but it's above the rings. There useta was pistons available to fit engines with sleeves removed and no further boring.
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