may be - R11A is on the 5-9 Chev rads I have, but the H numbers [Harrison] I've seen on them are all H-55, and the number I have off 1 is 3133342 .... there'll be a different design for Chev and GMC, and there may be different ones for big bolts
a good pic would help decide if it's the same as yours, or if you don't have one at all, get measurements to check against your core support
Bill
