Which gears you running?

['82 steppin]

I have the stock 3.08 with th350 and Im thinking of putting a 3.42 there and keep it highway friendly I had very bad experince with 3.73 with th350 on 25" tires on my Camaro and I dont want to make the same mistake
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[tinydb84]

3.73 with a th400. 30" tall tire. I'd rather have the 3.08
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[C-10 simplex]

2.56 with a 29" tire (235/75 15) Very "stiff," but otherwise happy with it for general comutining.

['82 steppin]

Should I stick to the stock gears?
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[C-10 simplex]

Well how fast do you want to drive usually and what rpm are you running right now?

[77c10]

3.08 with a 285/50/20. Wound pretty good at 70mph.

[hawksnest116]

Are 373 gears ok on the freeway? I have a 700r4. I am changing gears as well.
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[gchemist]

3.73 gears are great for any 28-30" inch tall tire with a 700R4. A stock engine should turn 1800-2200 RPMs at highway speeds.

I run 255/60R15 (27") with 3.08's. 70 MPH = 1950 RPMs. Best MPG 18.5.

[GM-power]

350/TH350 with 3.40 gears. At 65 its ok.. I normally drive 55 though.
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[frog210]

how do you find out the gears lol

[mopar346]

Look for a tag on one of the rear cover bolts near the top, not a guarantee that it hasn't been changed but a goo chance. With the cover off roll the gear and read the side of it, most have it printed in it. All else falls count the teeth on the ring gear and divide it by the number of teeth on the pinion gear.

Here is a helpful RPM chart that I snagged off of the CJ forum, it is based on 1:1 (none O/D high gear). You can open it to read it, but if anyone knows how to post it, please do.

['82 steppin]

Originally Posted by C-10 simplex

Well how fast do you want to drive usually and what rpm are you running right now?

With the stock 350ci and 3600stall its around 2200-2400rpm on 295/50/15 and now Im building a 383ci with lots of mods and the cam operation is 3500-7000 thats why I was thinking of changing gears to help little bit
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[mopar346]

There is very little reason to have a cam with that operatinig range in a street car much less a truck. I hope oyu have the rest of the components to go with it.

['82 steppin]

383ci internal balance roller block 6" rods Mahle flat top pistons with two valve reliefes
AFR 210cc 2.08/1.60 65cc chamber 80cc exhaust port
Victor jr intake
750 street HP
Full MSD
1 3/4" hooker long tubes
3600stall on Th350
Trick flow 246/254 .555/.555 on 1.5 rockers (i have the gold 1.6) on 112lsa
Moroso oil pan
Milodon diamond windage tray

Im sure I missed few things here and there
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[Cheng]

4.10 gears with sm465 trans & 6.2 diesel on stock 235/85R16 tires. I go everywhere at 55-60.

[Firebirdjones]

Originally Posted by '82 steppin

383ci internal balance roller block 6" rods Mahle flat top pistons with two valve reliefes
AFR 210cc 2.08/1.60 65cc chamber 80cc exhaust port
Victor jr intake
750 street HP
Full MSD
1 3/4" hooker long tubes
3600stall on Th350
Trick flow 246/254 .555/.555 on 1.5 rockers (i have the gold 1.6) on 112lsa
Moroso oil pan
Milodon diamond windage tray

Im sure I missed few things here and there
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That puppy needs some 4.56's,,,not 3.42's.

I run alot of different gears in various cars here, and find 3.73's about perfect for performance and very highway friendly in my opinion. With a 28" tire you can easily cruise at 65 mph at only 2800, and 70 mph isn't much more if you want to make a little time. I daily drive cars like this for years and criss crossed the country a few times.

I have cars with...

3.31 and 28" tire
4.10 and 28" tire
3.91 and 26" tire
3.73 and 26" tire
3.73 and 29" tire
4.56 and 28" tire
4.88 and 26" tire
3.73 and 33" tire

Only 2 of those listed even have an overdrive trans, and they both have 3.73's. The rest are 1:1. It's all a matter of what you get used to. I find them all to be friendly in their own way

Cruising at 65 mph is enough for me 90% of the time so I really don't care if I have an overdrive or not so most any gear works fine for me on the highways.

[blazer2007]

I just changed mine from 308 to 342 auto with 255'70 15 tires,I like it ,nice and peppy in town and seems OK on the hiway

[Firebirdjones]

Originally Posted by blazer2007

I just changed mine from 308 to 342 auto with 255'70 15 tires,I like it ,nice and peppy in town and seems OK on the hiway

No wonder it's highway friendly,,,that's a 30" tire I wouldn't find a 3.42 gear with a 30" tire peppy at all but then again, you see some of the gear setups I drive up above.

I'd have at least bumped that gear to a 3.73 and never thought twice about it.

[INSIDIOUS '86]

Originally Posted by '82 steppin

I have the stock 3.08 with th350 and Im thinking of putting a 3.42 there and keep it highway friendly I had very bad experince with 3.73 with th350 on 25" tires on my Camaro and I dont want to make the same mistake
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So I read all your posts and the others. This is my suggestion.

The th350 is no good. Look up PATC and find their raptor700r4 run a 3000 stall BUT also have a lockup torque converter and a lock up controller
Then add some 373s with a good posi and enjoy your overdrive and hwy mileage
Also be sure to run a trans cooler
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[mopar346]

Isn't a victor Jr. a dual plane intake? What is the operating range on it?

[Firebirdjones]

Victor Jr. is a decent sized single plane. Operating range is approx.. 3500 rpm and on up. It's what AFR recommends most of the time with their cylinder head packages on small and BBC.

Probably a good match given the size of the engine and camshaft used here. The 3.42's however are not if you want to see the potential of this package,,,lol.

[blazer2007]

Originally Posted by Firebirdjones

No wonder it's highway friendly,,,that's a 30" tire I wouldn't find a 3.42 gear with a 30" tire peppy at all but then again, you see some of the gear setups I drive up above.

I'd have at least bumped that gear to a 3.73 and never thought twice about it.

more peppy than the 3;08 ,s

[86c20]

i have an sm 465 with 3.42 gears and 235 75 16 ithink. would have to look at the tires and i get 21 mpg with a 350 with qjet and thats at 70mph

[USSkoval]

Originally Posted by Firebirdjones

No wonder it's highway friendly,,,that's a 30" tire I wouldn't find a 3.42 gear with a 30" tire peppy at all but then again, you see some of the gear setups I drive up above.

I'd have at least bumped that gear to a 3.73 and never thought twice about it.

It's all in how you look at it. That sure would feel peppy compared to my truck, it's the same 255/70, but with a 2.56 gear. What a slug.

[Firebirdjones]

Originally Posted by blazer2007

more peppy than the 3;08 ,s

Not enough of a change in my opinion to warrant all the work and money involved.