And I'm gonna be that other guy...

Rotating weight is more parasitic than static weight when it comes to increasing speed and reducing drag. If you're trying to go faster, then use the smallest wheel/tire combo that you can get away with and still hook up. The more tire you add, the heavier each wheel will get and therefore the more rotating mass you will add to the vehicle.

I made the same mistake when I was green and ran some 305 toyo TQ proxes when I could've gotten away with a 275 just fine. It looks cool, sure, but it won't help you if you want to actually see those times drop.

I learned the hard way. If you have no interest in drag racing then ignore me.
my 2¢

If you run a good tire in 275 you'll be just fine. I would recommend a 15" or 16" rear wheel and a good drag radial. Then for road course get some 17" wheels and some R888's. Jegs makes good wheels for cheap. They're light but durable my friend just crashed his hard with 15x4 fronts (aluminum) from jegs they took it in stride. Also, play with your launch and find out what rpm you are able to hook from, if you have to slip the clutch, etc...

at those power levels a 305 is definitely not necessary and will add unwanted weight

Well i borrowed a 315/35/17 mickey thompson off of my tire guy to see if it would fit. He has the same tire on his ws6 and told me me it would fit so he mounted it on my spare ws6 rim and put it on my car and it fits just fine i have about an inch of clearance all the way around. The tire mounted just fine on my factory 17"x9" ws6 rim very little tire bulge. Needless to say ill b ordering 2 of theese for my car

Just like they say you shouldn’t put a 275 on a stock 8” wide wheel. I did it anyways. I believe about 50% of what people regurgitate on forums and just try for myself. 275/40/17 nitto nt05r

I do get where you’re coming from. You see guys put the wider tires on narrow rims all the time with no issue. Unfortunately that doesn’t mean there won’t ever be one. The tire manufacturers have their specified rim width for a reason, the tire can fail catastrophically if mounted on a rim of improper width. I’m not chastising you for doing it though. I work for the largest tire dealer in the world and we won’t touch improper fitment anymore. So you can take what I’m saying with a grain of salt if you want, but if you came in with your car wanting to spend $1500 on tires and I told you I can’t do it because of improper fitment you have got to think it must be a pretty big deal and liability. Why would I turn away someone waving $1500 in my face? And in the location I work I turn away $2000+ deals all day long with guys wanting to put 35x12.50R17s on their duallys with factory rims. I can’t even just sell them the tires and let them go get them put on somewhere else. I would lose my job in a heartbeat.

You Tube

The left 315 the right nitto 275/40/17 extreme drag radial



My 315 fit just fi e

That was putting a 315 on my ws6 rim and on my car

My friend runs a nitto 555r on his bolt on LT1 trans am. But he's smart and runs a drag pack. 15's all around. 15x8 in the rear and 15x4 in the front. Rear Tire size 275/60r/15. Dead hooks every time. And we lost a ton of weight from his 18's. It outruns most other bolt on Lt1's because he and I went ahead and addressed rotating weight first. LS1 driveshaft, drag pack, lighter flexplate went a long ways. Again, if you're after the looks, go with the giant tires and rims. If you want performance, use the smaller wheel/tire setup that still hooks. Best of luck