Would this be a deal breaker?

Llike 1968FormulaS340 points out, you're going to need to budget a lot more to get the car where you'd presumably like to see it... but it IS a car worthy of the investment, IMO.

The quarters, rockers and doors seem to go first on these cars but it's a safe bet that the floor and the trunk are in trouble too... definitely lift up the carpet and trunk mat and bang around in there.

On the plus side, the parts are all out there and it sounds like you have the skills to do it yourself which would save a ton of cash.

Then there's the issue of the 318. Obvioulsy a fine engine but NOT what should be there. A nice '71 or '72 vintage 340 is also going to set you back as well.

Dealbreaker? I'm not sure...but my gut tells me that the asking price is a bit high.