Tire size impact on gearing

I am sort of twitting over what size tires to get for the rear of my ebody fish.

Currently have 235/6015....size would be 26" new....as worn, they are like 25.5 or so.

Considering 275/60/15 so I can get a more beefy look to fill my wheel well...the car is lifted in the back some and will have clearance that way. That tire would be about 28" tall.

But I recently changed from 2.76 gears to 3.54s.

I know going to a bigger tire will in effect take me backwards some.

Looks like going to a 275 would give me an effective rear gear of 3.31

Going with a 255 would give me an effective rear gear of 3.43 but they are only 1/2" bigger sidewall wise and not as wide in the tread.

With the current 235s, RPMs are about 3k at 65 mph give or take. 9Used to be like 2200 RPMs with the 2.76 gears installed and the 235 tires.

According to an online calculator , I would be spinning at 2800 rpms at 65 with the 275 tires and the 3.54 gears.

My question is, will I notice a loss of low end power going with the 275s?

Is that 200 RPM critical do you think?

My engine is a tweaked-up 318 with a cam that is strong up top, just OK on the bottom end. 727 tranny.