I'm just curious if anyone has some hard #s with how much they gained from doing a gear-swap(with general info such as power of motor, etc.)

I currently have a 81 Camaro w/ 3.42s that does mid/low 13s and I shift into fourth gear(manual) right before the finish line-cross the line around 4,500-4,600rpms. I'm just wondering how big of a difference I would see from swapping to 3.90s-it would put me at 5,100-5,200. I found best results with shifting at 5,700rpms or so. Thanks for the help.

Nick

what was your best 1/4 mph with the 3.42s?

what size rear tires are you using?

Originally posted by RatONaStick:
what was your best 1/4 mph with the 3.42s?

what size rear tires are you using? Best MPH with the 3.42s was 103. I'm also planning to swap out the world s/r heads for Brodix or AFRs so that should add 5-7MPH I would think. Rear tires are 26"

if your looking for all out performance i would go the 4.10 route and get all the rpms you can at the end of the track.

going with 4.10 now will allow 5,457 rpms thru the traps(based on your info.....26",4th gear,103mph)....knowing the mph will be faster with the gear swap you should see about 105 mph over the 103 because of making better use of the hp ....since you say that it runs best at 5700 this will put you right at 5,563 rpms.

now since you think maybe the heads will give ya 5-7 mph more ...so then your looking at a 112 mph run......then it is time for some 28"tires and this will give you a 5,510 rpms


for all out performance go with as much gear as you can to have the mechanical advantage.....and adjust the tire size as needed.

others have been told stuff as much tire as you can under the car and gear accordingly

being a stick car and trying to keep with in reason for tires size that fits well under the camaro.....i would run the 4.10's and just up the tire size as you need.........

besides once you start changing heads and what not the power band might move up on you and no longer the the 5700 rpm shift point is worhty....so now you shift at 6100 rpms and now your in the same boat with 3.90 gears as you was with 3.42 gears......comming up short at the end of the track.........

go with more gear...i say.....at least 4.10's