C20 307 engine whoes

[PWPrice]

Vet needs help. First off, I am restoring 69 C20 with a 307 Factory 2 barrel engine. Tore it down to replace timing chain and cover seal. Took off harmonic balancer which had NO BOLT. Need to know correct size balancer this engine came with because I Did not measure old one. I ordered a Pioneer Product 6.120 with degree marks from Summit. Second, after ordering this I find out it needs a different timing pointer since the TDC is not like OEM old one. Did I buy the wrong size? I have read the treads for installing a balancer with no bolt.