[Sirrotica]

On any multi cylinder engine you look at each cylinder as one small engine, They all contribute to the power at the shared crankshaft.

If someone hand ported a cylinder head, and got one cylinder flowing a small bit better than one of the other cylinders, does sthat hold back the better cylinder? Absolutely not, the cylinder that flows the lesser amount just doesn't add as much to total power output.

This theroy was proven many years ago when tandem engine drag cars made their debut. Some racers would use whatever engines they had access to. One guy I remember had a flathead V8 ford in the front, and an OHV Cadillac behind it. No matter that the engines were about as mismatched as possible, the two engines together pushed the unlikely combo to very impressive numbers. The engines were coupled together inline, so they were for all intensive purposes a V16 with totally different components, and engineering.

Having 2 heads that are not matched on the same engine will run just fine, it may not be optimum, but the OP isn't racing the car, so every last HP doesn't matter. people drive cars every day with one, or two cylinders down on compression due to mechanical problems, sometimes for years, and many thousands of miles.