[rubbinisracing]

Darren,

The first picture looks ok but there is not enough detail to see broach marks. I suspect the second picture to be a restamp. Someone has attempted to add or enhance broach marks on the pad. They are not untouched. Leeds cars do have 3/16" letters for the Engine code and the vin, with the vin being stamped upside down only at that plant. All other plants had the tonawanda number in 3/16" and the vin in 1/8" in 1970. I believe this started in 1967 with big block along with moving the tonawanda number to the left side near the head plug with the vin on the right.

Best way to tell is look for the following:

1.Check the block casting number... should be 512
2.Check the block casting date...should be within 3 months preceeding the build of the car and the Tonawanda date stamp
Tonawanda date should be within a month precceding the build of the car on build sheet or cowl tag
3. Make sure the block is a 4 bolt...this can be done without removing the pan. 4 bolts have larger holes in the side of the block near the oil filter. There are 3 holes in this area. the center hole of the three is tapped 3/8npt on 2 bolts and tapped 1/2npt on 4 bolts
4.Check the head casting numbers....should be 291
5.Check the head casting dates....they should both be very close in date and follow the 3 month prior to build to build date of car and 3 month prior to Tonawanda date.
6.Pull the heads...broach marks should run from front to back accross the entire top surface of the block. If broach marks are not visible then the block has been decked. It is possible to deck a block and leave the stamp pad untouched. If thats the case then take a metal straight edge and put it on its side accross the top of the block with it running across both the stamp pad and the decked surface. There would be a slight ridge or area where light would appear under the straight edge if this were done. If not the entire surface was decked and pad restamped.

The date codes are a rule of thumb and don't apply to copo engines. I usually perform in the order I outlined as its from easiest to hardest and usually don't have to go all the way. Remember that when you sell the car, someone may go to these extremes to determine if the block is original and you could end up with egg on your face if you didn't do your homework. It's not foolproof, just the best way I know.