MSD Street Fire HEI trouble
I just bought a new MSD Street Fire HEI distributor for my mild 350 SBC. It's running perfect under 3500 rpm. When the engine is under a load, over 3500 rpm, it's missing a lot. It was running fine with a stock GM HEI that I had on it. The GM HEI was my brother's so I had to give it back to him.
Any ideas on what might be causing this? It's not fuel problems because it was running fine before.