Ya,i missed that 90/90.You are definetly down on power somewhere,should be at least 440 with a m6.is the shortblock new,maybe the rings did not seat.You should have a leakdown test done,and a compression test, before writnig off that cam and head combo.I put down 433 on a mustang dyno though a a4,would be somewhere in the 450 range on a dynojet.Did you dyno through the muffler? That will kill 20 hp,from an open cutout.

 

Ya I dynoed it through a muffler, and the block is new it had 1000 miles on it when i dynoed it. Now there are about 3-4kmiles on it, but what would be a sign of my rings not being seated? Thanks

 

Were your numbers with a dynojet or mustang dyno? If you have 3-4k miles on it now, the rings should be seated already. 1k miles is a little low to be dynoing it in my opinion. Don't blame the cam and heads just yet as alot of times you need to tweek things here and there to get the combo to work right. With a little patience and a methodical approach, I'm sure you'll figure out what's wrong.