I was told they were LT4s but i am not sure, the casting number is 10207684 or 10207643 i am not sure on the last number. the only other number on the heads i 5348. Any help is appreciated.

 

Maybe you can take a photo of the intake side and send it, will be easier to tell.

 

i dont have a digital camera, what is the difference?

 

anybody?

 

intake ports are raised .100", chamber size smaller by about 4 cc's

 

A good comparison here:
http://www.grandsportregistry.com/lt1vslt4.htm#HEADS
The most noticible difference is the ridge below the valve cover on the intake side. On the LT1 it is thick about 1/2", for the LT4 its only about 1/8".

 

As far as the extent of potential, LT4 are better. You can do more with the raised ports and other good stuff.

TFS has been making good castings but their heads have a larger combustion chamber which is good for boost motors, but not as good for N/A motors unless you mill them.

 

I plugged 10207643 into a google search, and came up with this link:

http://www.chevy-camaro.com/SBCheads.asp

It shows:

"10205245 1993 350
10207643 1994-96 350 "

That would suggest its an LT1 head, since the LT1 didn't exist in 94.

 

If 10207643 is the casting number for LT4 heads, my 1995 LT1 came stock with them!

 

My LT4 heads have casting # 12555690

 

OK.... pulled both of my 94 Formula's original/stock LT1 heads out of the parts pile in the garage, and its 10207643.