i've seen it done with a header with a part that goes in on the exhaust port to separate the two cylinders.... dont know how well it works, i'm sure theres some seepage still.... only really works good though if put all the other goodies on her too.... btw 300s are a great motor with a lot of capability.... for a long time at the el cajon speedway here(before it was shut down) a local builder was running a car with a 300 on the circle track that was just killing all the v8 cars.... he was boasting 400 HP NA