Rhino79

iTrader: (7)

Ok so my lil 4.8 has 243's, what springs and valves do the NNBS truck's version of 243's come with? Are they still the 64cc chamber like the ls6 version?

hirdlej

iTrader: (31)

Same casting head, standard valves, springs unknown.

silver-mod-o

iTrader: (15)

Wrong...09's are GEN IV... Square port stuff. Unsure if chamber size is different.

Dewey

iTrader: (1)

why would they have the same casting number if they were different

caddy03pimpin

iTrader: (18)

No he is correct... 243 are 243.. There is no difference in them or they would have different casting numbers

Rhino79

iTrader: (7)

Do they have the LS6 springs??

1slow01Z71

iTrader: (36)

Pull the oil filler tube and you can see the springs easy, if theyre yellow youve got the LS6 springs.

Rhino79

iTrader: (7)

From what I've found online, the only difference between them and the LS6 vette heads are that the valve seat material was changed for higher mileage durability and and the valves are standard valves not the sodium filled version, and supposedly they have the LS6 springs.

Rhino79

iTrader: (7)

Popped the oil fill tube out, springs are not yellow, may call the dealer tomorrow and get the part# for them and try to cross reference them.

max1

iTrader: (12)

243/799/ ls2/ls6 share the same Combustion chamber ( 64CC) valves are 2.00/1.55
the only difference is that the ls6 have sodium filled valves and have ls6 yellow springs.

and they have catheral ports , not rectangle*