Front crankshaft threads

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Thanks for the info megaladon, Yeah the threads are only bent at the very front of the whole. btw whats a thread chaser???

It looks like a conventional 4 fluted tap with the exception of how deep the actual cutting is (sometimes a worn out tap will suffice) It may have a hex head on it rather than a square. FWIW you will be looking for a 3/8-24 NF tap or thread chaser. Hope this helps.

i believe the crank thread is a 7/16ths fine thread

just everything else on the motor is 3/8 24

Yes my bad on the thread. The crank snout on a sbc is 7/16-20 NF. Most of the accessory holes are 3/8-16 NC. To answer the question of how to, well try this. Find an old tap and using a bench grinder with a fine wheel, gently grind away the first few threads partially. That will help start the tap as someone else mentioned. Depending on how bad you compressed the old threads is what will determine your success. Go slowly and it should not take much effort as the crank material itself is soft. 1/2 to 3/4 of a turn in, then back it out a few times and you will feel it "free up". If it stays tough more than three or four full revolutions, it may be time for a heli-coil.

Good pictures uneek....