New to LS engines...
#1
New to LS engines...
I'm getting ready to build an engine to either do a Z car or Miata.I picked up a L33/LM4 5.3 shortblock casting number 12572733. I've been told these engines originally came with the 799 heads. My first idea was to build this up with 243 heads and a LS6 intake. Would it be that big of a difference with the 243 heads if I can find the 799 ones easier or cheaper and then just get a custom cam done? Anybody happen to know how much it would change the compression if I did go with the 243 heads instead of the 799?I'm new to dealing with LS engines so I'm just trying to soak up some knowledge. Any help and info you guys can throw my way will help!
#3
Oh ok I was under the impression that the 799s and 243s had different size combustion chambers which would ultimately change compression. So what are the differences between the two besides the shape of the ports?
#4
TECH Fanatic
799's and 243's are the same castings. I've even heard of someone finding a 5.3 with 1 799 and 1 243. Either way the only difference between a 799/243 head and a true LS6 Corvette head is that the LS6's had lighter valves.
#5
Ok great. Thanks for the info guys. I actually found a set locally today for cheap so I snatched em up. Now time to start the tear down on them and the shortblock so I can start the rebuild!