Upgrading my 340

ok now that im up to speed.

yellow rose said: ↑
Don't waste your time with a 6 pack.

The real question is what's wrong with what you already have. I doubt I would have used a 650 just because the booster swallows bilge water but that can be addressed.
could you educate me on that?

Now whether you go with efi or a bigger carb, you combo need to be dialed in first! as has been ask do you know you initial timing, how about total timing? this would be the first you need to know. Do you have a timing light to check?

OK let me Back Up a little bit here. You have the eng in the car? if so, what is the least exciting part about driving it?
What part of driving it, do you want the motor to do better?!
answering that, will help us all, help you..............