I read the first sentence and I gagged.

The 7027 is NOT a 6L6. It handles much more voltage and delivers more wattage. The impedances are not the same, but similar. It's closer in output to a 6550.

To run 6550s is a simple mod. I would NOT want to run 6L6s in a V4, and EL34s just sound mushy. So, look for new production 7027s (NOS cost a mint) or look at 6550/KT88s. The advantage of 6550-types is availability and price.

"Tyranny, like hell, is not easily conquered… What we obtain too cheap, we esteem too lightly: it is dearness only that gives every thing its value. Heaven knows how to put a proper price upon its goods; and it would be strange indeed if so celestial an article as FREEDOM should not be highly rated."
-Thomas Paine