For sale are 2 NOS Chevrolet Square Port 454 Replacement Heads. Part number is 6260482. They are both brand new in their original GM boxes.
They're in perfect NOS, brand new condition with no porting, polishing, grinding or any other modifications to either of them.
They have never been bolted on an engine and they were only taken out of their boxes to take these pictures.
The factory OEM casting number on both of these heads is 6272990 (see all of the pictures).
These will fit on all Big Block, Mark IV 396, 427, 454 engines made 1965 to 1975.
These castings are 2.19 intake valve size and the 1.88 exhaust size.
These combustion chambers are the 118cc chambers.
Picture number 11 has the number "101" in between two marks that look like screwdriver slots in the castings. We're not sure if 101 is a date code since it doesn't follow the conventional dating format on other big block Chevy heads that we have seen of this vintage.
This GM casting was produced from 1971 to 1994 (These were purchased in the late 1970s); and this casting has been discontinued.
These heads have the same 325cc intake port size as the original LS6 108cc L-78/L-71/L-72/LS-6 Rectangular port heads with the 3964291 head casting. These heads are High Performance 454 Big Block Chevrolet LS6 or LS7 replacement heads and they have 118cc "open chamber" combustion chambers. They are both "New Old Stock"
there is a set on ebay and they are asking 4000.00 for them i will let my set go for 2000 obo so if ony needs them let me know my email is [email protected]