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nats68
02-17-2015, 07:22 PM
I've got a 1968 Camaro with an LS3/4l65e. 8.5 10 bolt rear end and 275/40-18 rear tires. That's a 26.6" tire.
I'm gonna get the rear end rebuilt, regeared and add posi.
The car is gonna be a cruiser, no racing in its future.
I plan on a lot of highway miles.
I was between 3.42 and 3.73.
I know from the calculators there's only about a 200 rpm difference between the 2 at highway speeds.
Which would be the better of the 2 for off the line? I know 3.73 will be better off the line but is there gonna be a huge difference between the 2?
How will the first and second gear ratios in the trans effect the overall performance?

Z06vet
02-17-2015, 07:55 PM
With the automatic and cruising/mostly highway, I'd run 3.42. It will be very smooth at 80 mph and knock down great mpg. With a stock LS1/4L60, performance tune, long tubes, and 9" open element filter I can shred the tires thru 1st & more than halfway thru 2nd. This is also with an 8.5 and exact same tire/wheel sizes. I have built several with this same setup. The trans has a steep 1st gear, allowing good perf out of the hole. Where the 3.73 would help most in my experience is keeping the rpms in the sweet spot on each upshift. To me this was most noticeable at the drag strip under WOT. Scott

nats68
02-17-2015, 08:19 PM
That's what I as wondering, how it would react from 1st to 2nd gear. As long as there's not a huge drop off between gears I'll be happy with it.
Sounds like 3.42 are what I want. Don't get me wrong I will shred the tires here and there but it's not a priority.