"wow thats way to high" ....whoops meant to low ha ha

 

A 295/35-18 is a 26.1" tire. Not much different than what you have now.

I run 28" slicks, and the rear sits way too high to look decent on the street. I wouldn't want that much rake on the street. I had to cut the bumper cover for 28.1" ET Drags. I don't think you can fit a 29" tire without a can opener.... maybe.

http://www.injuneer.com/images/photos/DCP03466.jpg

 

ha ha, yeah I did not realize it was that small of a difference. So... anyone out there want to contest that for a streetable car, that i don't want to open with a can opener, with 408 rwhp, s 60 rear end, cam with an optimum range starting at 2000 rpm, and 26" tire, not something that i ever plan on turning into an all out drag car, 4.56 would be too low, and 4.11 would be the wiser choice for this situation?

 

There is an 1/8 mile strip about 70 miles from me in walla walla washington and a 1/4 in spokane wa about 100miles away. In boise area is firebird raceway not sure about your way. We have alot of no traffic paved roads and alot of people take advantage of that but very few of them are quicker than 12,s. The kooks are nice, very well built and fit was probably top notch as far as longtubes(should be for the price) but havent fired up my car yet with them as most of my parts are new on my new longblock and had to pull motor back out cuz had several headstuds leaking with no pressure in system. I just got motor back in saturday and a few more hours and will be ready to try and fire her up. As far as gearing if your not trying to get the last tenth of a second out of her id go 373 if you want to have a good daily driver all around car with very little sacrifice. I personally wouldnt do 456 if your gunna drive it much out on the highway. Id be tempted somewere between the 373 and 411 personally. With my truck I really liked the 373 better on average as I could hold a higher speed on hills using a lower gear and it wiped away my top speed lol.

 

When my Formula was still a 6-speed, I had 3.73's in my Strange 12-bolt, and wished I had gone with 4.11's. That 0.50:1 O/D actually becomes more usable. I would not run 3.73's with a T56.

 

Against my better judgement(because now ill be looking if I want a gear swap) why didnt you like it fred? I havnt driven mine in two years but before she went down I was getting 25mpg and had a 120mile commute for different periods of time. I also do some road racing and absolutely love that gearing on them. It wasn't bad at the 1/4 or 1/8 either(not optimal for my setup but should be closer now) but then im not looking to build it around the strip. Previous motor on spray at a 15mph roll start got alot of traction even while spinning(street tires on the street). For me the corners are more important than the straights and fuel milage is pretty important and I do like a top speed above 150(given the car is worthy). Did you end up running 411 or just knew you wanted a lower gear? What power level were you at too? Just curious because respect your opinions and value your experience and finally after two years my car is about to hit the streets and gearing selection does make a difference and had just been guessing how the new setup would do with current gears.

 

The bump from 3.42 to 3.73 is 9%. Going from 3.42 to 4.11 is a 20% increase in effective rear wheel torque. I didn't think the 9% increase was that significant. I wouldn't hesitate to use the 4.11's in a daily driver with the T56.

Now with the TH400 I've got my 4.11's and a Gear Vendors O/D to keep the freeway RPM somewhat rational. But I wouldn't use it as a daily driver. Unfortunately it's been way too long since it's even been out of the garage.

 

The stock 3.42's are just rediclious, its not even that fun to drive unless you are out on the freeway (never get out of 2nd gear in town), so for me the 3.73's never were an option. Just don't want to get the 4.11 and wish I had gone with the 4.56. Again, however it sounds like the 4.11 would be the conservitive and probably best choice here.

Fred, What percent increase would the 4.56 gearing be? Or how big of a jump is it from 4.11 to 4.56? Its almost double from 3.73 to 4.11, but i am guessing it is only like 5% more from 4.11 to 4.56? That puts it into perspective.

 

The math is simple. Say your car cruises at 1500 rpm at 65 mph with the 3.42 (not sure what it really is), the math would be

Where X = desired rpm

1500/3.42 = X/4.11
(1500*411)/3.42 = X
1802 = X

1500/3.42 = X/4.56
(1500*456)/3.42 = X
2000 = X

There's more to it than top gear rpm though...

 

4.56 / 3.42 = 1.33333

It would feel like you added 33% more torque at the rear wheels. But you run out of RPM at 75% of the MPH you would run with 3.42's.

Check an RPM calculator. You don't want to have to shift into 5th gear at the end of the track. For example, with 3.42's, a 26" tire, and a 6,000RPM redline, you could reach 136 MPH in 4th gear.

3.42 - 136 MPH
3.73 - 124 MPH
4.11 - 113 MPH
4.56 - 102 MPH

With a basically stock car and the 4.56's, you'll be close to redline thru the 1/4-mile traps. Any extra power and you have to shift into 5th. With an 11-second car, you'll have to go to a 28" tire, and even then you're only at 110 MPH. Or just go with the 4.11's.

I remember back in the days of the 283 and 327 Corvettes, with the solid flat tappet cams, 4.56's were a factory option. The car was lucky to get 10 MPG, but gas cost less than 50-cents a gallon, so nobody cared. And the sound of the solid lifters was fantastic.