i got a set of tp heads the other day. one head is very interesting. one head is a c7-k but the other head has no casting numbers at all. on both ends of the head(where the atl. would bolt) it has stamped: SK36228
$15A
fw1
the fw1 is stamped real small. it looks like it was hand stamped. it also looks to be ported compared to the other head. the exhaust side under the ports also have numbers stamped under each one. the numbers are 735-739. in no order and missing some. i would think maybe flow numbers but the numbers are too big. it also had 901-907 stamped ther but they were x-out. any thoughts? also one needs some casting repair. more than just pinning. anyone recomeded?