Customs What rear end should I use?

I have a chev 350 with 350 trans and I have two rear ends I can use. A 3.42 or a 3.08 both posi. Wondering what others have used? Looking for good acceleration but still be able to use the highway. What are your RPM on the highway. I am sure you guys have the answers . Thanks

 

Put the 3:42 in there. You and your engine will be happier. Forgot and had to edit- Tire size will have alot to do with this as well. I just ***ume everybody runs about a 235/75 on the rear. But if it's a small rear like a 6:00 you will need the 3:08


Tim

 

Ive had a few cars/trucks with 350s and 700R4 and 4spd manual, with 3.08s
so if I was using a TH350, a 3.08 would be my choice for sure.

But I like to cruise down highway with ease.

My buddy has a 3.42 behind a 235 inline six and 5spd, and it runs 2k rpm at 75.

Any of this help??....

My .02

 

Rear tire size is a major factor in determing which ratio will work best for your intended use.

There are rpm calculators on the HAMB.............do a search

Ray

 

Those two are so close I don't think you'll even notice the difference in seat of the pants feel. Go with the 3.08 for more highway friendly cruising.

 

I'd like to know more about how hot or tame your engine and cam set up is and what rear tire size you are running before I answered that one. The other question is "what style of driving do you do primarily" short in town stuff or long highway trips?" If your cam is happy at 2000 rpm and everything is running smoothly at 60 mph then you're probably OK at 3.08. If you engine lugs and runs like **** at 2,000 but runs well at 2,400 then I'd go with the 3.42. Like someone said there are lots of rpm calculators available.

 

To me it depends on what kind of driving you do. If you cruise around town and like to pull away at the stop lights, go with a 3.42 or 3.70 etc. If you want highway comfort without high rpms go with the 3.08. With a 350 tranmission you have a 1 to 1 top gear ratio so you have to choose, short gearing or tall gearing. My 39 chev with a 350 engine and transmission combo runs a 1957 chev 4.11. This pulls great but turns high rpms on the highway. I will change it to a 3.08 in the near future. I run P225/70 15 tires that are 26 1/2 inches tall.