90mustang5.8

i cant decid between 3.73 gears and 3.90 gears.....................i know for sure i dont want 4.10's because that a little steep for the street. what would be the RPM difference between 3.73's, 3.90's, and 4.10's? i have a 3-spd auto C4 trans. i really dont want to be reving the engine higher than it can handle at the finish line..

-thanks

AdderMk2

what are your current planned engine mods for the 351? If you use TOO much gear, youll top out the RPM's before you hit the 1320 mark.

90mustang5.8

here i just copied all my plans for this year.

engine
-edelbrock performer intake
-600cfm edelbrock carb
-k&n air filter
-hooker LT headers

tranny
-stock torque converter, C4 3-spd


suspension
-90/10 and 50/50 lakewood struts
-UPR upper and lower adj. control arms
-sub frame connectors
-4 cylinder springs

weight removed
-no front sway bar
-no a/c

rims and tires
-centerline convo pro aluminum rims, 15x8...4.5" backspacing rear, 15x4....1-3/4 backspacing front, 255/60/15 M/T Drag Radial rear tires, 26x4.5x15 M/T ET bias ply front tires.




...stock heads, not sure about the cam tho. when i bought the engine he said the cam was new, but when me and my dad listened to it run.....its was pretty much stock, but my dad said by the sounds of it, the cam might be wiped out. stock is around a .470 lift i think.


next year i plan on a 750 carb, afr 185 heads...and some other stuff

AdderMk2

I've got an edlebrock performer cam that im looking to get rid of. Its out of my 71 AND I have the tappets lined up to match.

lemme know if your interested.

$60 shipped

*edit* cam had 200 miles on it so its barely broken in

90mustang5.8

i'll keep that in mind......the cam might be find, i dont know yet. if i need a new one i will give ya a pm.


anyways........................ what is it for gears?

AdderMk2

i'd say 3.90's might be just about right for you. If not, find someone on here that will buy those rear tires from you, and go with a set of 275/60/15's instead... the added height would help with your top speed at redline

90mustang5.8

ya but with 4.5" backspacing i cant fit 275's.....they will stick out hard core. plus i think 255's look good....there are 27" tall so w/e

AdderMk2

your the goober who wanted 4.5" bs....

90mustang5.8

not my fault the rims i like only come in 4.5" backspacing.



i like them way better then the draglites every race fox has!!

LTnone

There really isn't a terribly significant difference between 3.73s and 3.90s. Much like there isn't a huge difference between 3.90s and 4.10s. Any would work, with the future plans I'd stay away from the 4.10s unless you plan on some good suspension work (you should anyway)