oggie442

Okay been thinking about my gears in my car I have 3.42 rear came out of a 1969 442 4 speed car.
My set up is 455 with A/C, 350 trans with 3200 stall with 3.42 with 295-50-15 tires now. (currant)

When i first bought it back it had 235 60 15 tires on all 4 corners. It would just scream (RPM'S) going down the road, so I changed back tires to 295-60-15 and wasn't to bad. I really didn't do any highway driving just local driving. But when I get it all restored I plan on driving some long distances with it
Question is should I swap the rear end ? And what gears do I want or need ?
And How much is the 1969 442 3.42 rear worth ?
I still want it to haul *** and have a posi rear __________________

billmerbach

I'd assume something in the low 3.0something will be good am I wrong guys

BlackGold

235/60R15 tires with a 3.42 rear shouldn't "scream" unless you drive over 80 mph. I guess everyone has different tolerance. But are you sure you got the numbers right?

Speaking of which .... are your 295s 50 series or 60 series? You said both.

oldcutlass

With your current tire and gear ratio, your at 2600 rpm @ 60 mph, and around 3000 @ 70, that's not bad.


Here's a good calculator you can play with:


http://www.angelfire.com/fl/procrastination/rear.html

coppercutlass

I had 3.42's with a 26 in. tall tire it cruised real nice on the highway . The 3.73's are right on the verge of being annoying on the highway but I don't really mind it although between the 3.42 and 3.73 its very noticeable . 3.08's don't quite cut it for me in the acceleration dept. If you are going on long drives try a 31 in. tall tire. No joke I have a friend with a 70 ss chevelle and he tosses some chevy rallyes with a tall truck tire 31 in. or so to bump his 3.90's down. For the track he uses 275 50 15's which is what I also run at the track I run 275 60 15 on the street.

oggie442

I have 295 50 15 on it now

oggie442

Okay Thanks

oggie442

Thanks
I haven't run the tires down road yet (295-50-15)

BlackGold

Well just so you know, the 235/60R15 tires are 26.1" dia, and the 295/50R15 tires are 26.6" dia. So the 295 will (in theory) slow down your RPMs only 2%. That's nothing. In reality, the actual revolutions per mile of each tire might be slightly different than the calculated diameter.

70cutty

I have 3.42 gears with 295/50/15 and this is just about right. 3000 rpm @70mph.
It's really not that bad. I had 2.56 before swapping to 3.42, it took a while to get used to the higher rpm sound on the freeway.

oggie442

Thanks guys !
I guess I will keep what I have. The new tires (295-50-15) were given to me so I will give them a try with the 3.42 gears

70CCV

What transmission are you running?

507OLDS

Chris,
If you still decide to change,I have a 3:23 posi,but I am not sure you will see much difference. I think the rpms will drop about 400rpm.
I could possibly build a 3:08.

oggie442

350

oggie442

Brian, Thanks, I think gonna stick to what I have for now and try it.