i was just looking through the casting number provided by a few websites. the head on my car are the 101xxxxxxx casting which is said to be the 53cc lt1 aluminums. i had my heads cc'ed last year and they were 56.6 after they were milled, implying that the heads were 58cc originally. whats the deal on this?

 

you had them ported, or milled? milling the head will make the chamber smaller, porting it will make them bigger.

 

as stated, i had them milled and then cc'ed. they spec'd out 56.6cc after they were milled. that gives me evidence that they were 58cc heads originally before they were milled. no porting was done in the chambers. it confuses the hell out of me because the castring numbers are identified as "53 cc angle plug aluminum gen II lt1" in all the gm archives i can find.

 

anybody have any clue?

 

my stock ones are just under 54 cc's so I am at a loss.

 

Stock is 54CC's for an LT1.
Somebody needs to learn to CC a head or they are not stock.

 

actually, most were 54cc's but there were some 58's. most places advertise them as 58cc heads, but most were in fact 54. there are some 58's out there and i happen to have a set. since there are a million 54cc aluminum lt1 heads out there, it's tough to find a set of 58's.