So I just bought a 1967 Firebird 400 and I am trying to figure out what engine it has in it. There is an envelope with a bunch of receipts and a hand written note about the engine. It says, "77 Pontiac 400 6.6 Motor. Stock except a RV cam 268 intake 271 exhaust .447 lift 110 lobe centers" Sounds fine, but the numbers are as follows... Engine Code is YU. The casting number looks like 500557. The date code looks like I307. The only number I am sure of is YU. The other ones have been painted over and are a bit hard to read. The heads are 7K3, which would be 1972, 96 cc.
The YU code and the others don't seem to match. Any thoughts?
