Matching Numbers?

Theres no such thing as "numbers matching" in a mustang. Only corvettes stamped the VIn onto the block. The only thing u need to check is the date coding on the block. Basically if the date is close to the build date then its probably original. As long as you replace your engine with a small block engine you will most likely not lose too much value becuase a small block is a small block.

golf4283 said:

Theres no such thing as "numbers matching" in a mustang...

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Although not entirely acurate, its true enough for a 66 a or c code mustang. The block will have a date stamp (as stated) on it and for concourse competitions that date stamp has to be close to the build date of the car....you would lose points if you have 67 289 block in you 66 car for instance....as for decreasing value...any effect you get by replacing the block will be miniscule in my opnion....with that said......I wouldn't replace the block unless it was already bored out to .060 or had a crack in it anyway...unless the car was a daily driver and needed to be running all the time so you just wanted to pull an old motor and put a new one in some Saturday afternoon.....if its a toy...take the block out, strip it down, send to a shop for clean up and rebuild (or do the rebuild yourself).....

As for costs....99 times out of 100 its cheaper to rebuild and reuse many of your parts than to buy all new.....if you tear it down and find out you need a new crank and all new rods etc..that's a different story...but for a stock rebuild....many of your inernals are reusabele