I have a 1969 340 that is internally stock. I have a 8 3/4" rear end with 3.23 with a Dr Diff posi, A new Holley EFI, Hooker headers and MSD with an electronic distributor. With that she is just not very fast. My question is what would add more power, a cam or new heads? or would both be best? Any advice would be appreciated.
You should 100% verify the tune. Do you let the EFI control timing? Most times I see this on the forum and people end up regretting doing that. Do you know what kind of timing curve it has? That would be the first thing I would check.
