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-   -   Which gears you running? (https://67-72chevytrucks.com/vboard/showthread.php?t=543019)

'82 steppin 09-14-2012 12:30 PM

Which gears you running?
 
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 09-14-2012 12:43 PM

Re: Which gears you running?
 
3.73 with a th400. 30" tall tire. I'd rather have the 3.08
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C-10 simplex 09-14-2012 12:51 PM

Re: Which gears you running?
 
2.56 with a 29" tire (235/75 15) Very "stiff," but otherwise happy with it for general comutining.

'82 steppin 09-14-2012 02:21 PM

Re: Which gears you running?
 
Should I stick to the stock gears?
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C-10 simplex 09-14-2012 03:04 PM

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

77c10 09-14-2012 03:08 PM

Re: Which gears you running?
 
3.08 with a 285/50/20. Wound pretty good at 70mph.

hawksnest116 09-14-2012 05:01 PM

Re: Which gears you running?
 
Are 373 gears ok on the freeway? I have a 700r4. I am changing gears as well.
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gchemist 09-14-2012 05:15 PM

Re: Which gears you running?
 
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 09-14-2012 06:25 PM

Re: Which gears you running?
 
350/TH350 with 3.40 gears. At 65 its ok.. I normally drive 55 though.
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frog210 09-14-2012 08:08 PM

Re: Which gears you running?
 
how do you find out the gears lol

mopar346 09-14-2012 08:15 PM

Re: Which gears you running?
 
1 Attachment(s)
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 09-15-2012 05:08 AM

Re: Which gears you running?
 
Quote:

Originally Posted by C-10 simplex (Post 5592450)
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 09-15-2012 05:55 AM

Re: Which gears you running?
 
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 09-15-2012 06:38 AM

Re: Which gears you running?
 
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 09-15-2012 09:37 AM

Re: Which gears you running?
 
4.10 gears with sm465 trans & 6.2 diesel on stock 235/85R16 tires. I go everywhere at 55-60.

Firebirdjones 09-15-2012 10:16 AM

Re: Which gears you running?
 
Quote:

Originally Posted by '82 steppin (Post 5593364)
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
Posted via Mobile Device

:lol: 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 09-15-2012 10:18 AM

Re: Which gears you running?
 
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 09-15-2012 10:23 AM

Re: Which gears you running?
 
Quote:

Originally Posted by blazer2007 (Post 5593523)
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 :lol: 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 09-15-2012 01:53 PM

Re: Which gears you running?
 
Quote:

Originally Posted by '82 steppin (Post 5592267)
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 09-15-2012 02:01 PM

Re: Which gears you running?
 
Isn't a victor Jr. a dual plane intake? What is the operating range on it?

Firebirdjones 09-15-2012 03:25 PM

Re: Which gears you running?
 
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 09-16-2012 10:24 AM

Re: Which gears you running?
 
Quote:

Originally Posted by Firebirdjones (Post 5593532)
No wonder it's highway friendly,,,that's a 30" tire :lol: 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 09-16-2012 10:33 AM

Re: Which gears you running?
 
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 09-16-2012 11:06 AM

Re: Which gears you running?
 
Quote:

Originally Posted by Firebirdjones (Post 5593532)
No wonder it's highway friendly,,,that's a 30" tire :lol: 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 09-16-2012 11:13 AM

Re: Which gears you running?
 
Quote:

Originally Posted by blazer2007 (Post 5594983)
more peppy than the 3;08 ,s

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


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