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Old 04-06-2011, 08:01 PM   #1
dave666693
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front and rear end gears??

I am putting together an off road/urban crawler type Blazer. Since it is road and off road I am thinking about 3:73 gears with posi front and rear. 35" tires and a 383 stroker. Plenty of torque I am guessing for the 3:73 gears. What do you guys think?
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Old 04-06-2011, 09:08 PM   #2
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Re: front and rear end gears??

I'm running 35's with 3.73's in my K5 and I'd go a little deeper in the gearing department. Granted, my little 350 is of unknown age and tired, but even with more power your loosing a lot of that torque just getting the 35's rolling. 35's and 3.73's is roughly similar to 33's with 3.42's. 35's really are best with minimum 4.10's or 4.56's. Since you are seeing some street time, 4.10's should give you the best of both worlds.
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Old 04-06-2011, 09:08 PM   #3
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Re: front and rear end gears??

For 35's I'd go 4.30 or 4.56 for the gears. That will move the tires pretty well!
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Old 04-07-2011, 03:12 AM   #4
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Re: front and rear end gears??

How old is the blazer? What trans are you running? If you have a 700R4 my vote is for 4.56's, if no OD then 4.10. The 208/241's have a deeper low range, which is nice if it is a later model truck.
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Old 04-07-2011, 09:08 AM   #5
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Re: front and rear end gears??

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How old is the blazer? What trans are you running? If you have a 700R4 my vote is for 4.56's, if no OD then 4.10. The 208/241's have a deeper low range, which is nice if it is a later model truck.
It's a 71 Blazer. Probably going to run a TH350 trans.
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Old 04-07-2011, 09:59 AM   #6
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Re: front and rear end gears??

Here is a gear/tire calculator http://www.4lo.com/4LoCalc.htm
This will help you find a cruising rpm you and your truck can live with.
Posted via Mobile Device

Edit: BTW 488 is what I like with 35s. But my Blazer is more of an around town street and off road weekend toy. Not a daily driver. Also, I'd go with an electric locking front. Not all time posi. Full time up front makes it a bear to steer when you need it but 5% of your off road driving. Detroit lockers are my fav for the rear.

Last edited by Torrey72; 04-07-2011 at 10:10 AM.
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Old 04-07-2011, 02:16 PM   #7
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Re: front and rear end gears??

so what front and rear end should a guy be looking for? Dana 60 and 44 with 4:11's and posi? What posi or locker from our era is the one to get?
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Old 04-07-2011, 02:55 PM   #8
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Re: front and rear end gears??

Srew the gear ratio, lets see the Blazer!!!!
For me, I have 35's and the stock 3:73 gears front and rear, but I have not driven it yet. Mine will also be on and off road. I looked at it this way, get it on the road and then upgrade later
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Old 04-07-2011, 02:55 PM   #9
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Re: front and rear end gears??

So you are running a 383 through a th350 with 35's? How fast do you plan on driving on the high way, and what sort of off roading do you plan to be doing?
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Old 04-07-2011, 04:32 PM   #10
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Re: front and rear end gears??

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So you are running a 383 through a th350 with 35's? How fast do you plan on driving on the high way, and what sort of off roading do you plan to be doing?
normal city and highway driving. 65 mph max

offroading would be mud holes and trails.
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Old 04-07-2011, 04:59 PM   #11
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Re: front and rear end gears??

Well, at 65-tops I think a 4.10 is the way to go. Trying to factor in things like transmission slip, and such I think that will put you at a decent middle of the road. If you don't mind nipping at the heals of 3000RPM at 65MPH then 4.33 is the next best option.
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Old 04-07-2011, 05:27 PM   #12
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Re: front and rear end gears??

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Originally Posted by Altec View Post
Well, at 65-tops I think a 4.10 is the way to go. Trying to factor in things like transmission slip, and such I think that will put you at a decent middle of the road. If you don't mind nipping at the heals of 3000RPM at 65MPH then 4.33 is the next best option.
+1
I bet anything over 4.10 is going to bother you as for how much you would be revving the crap out of the engine. If you travel often on the freeway, 3,000 rpm starts to feel like your abusing your engine. I have 4.56s in my jeep with 35s and I have to drive under 60 on the freeway or the 401 will start overheating. it is fun off road but not so much if I need to go places. How you build the 383 in regards to its usable power output plays a factor as well.

Dave, we really can't give you a description of the perfect setup. That is kind of an individual preference. It is almost like us picking what music you should listen to. For instance, you can keep the Dana 44s and funky stock steering set up. if you're into the factory look. Or on a budget. Or you could , say, put a Dana 60 up front with crossover steering and a 14 bolt FF in the rear. complimented with disk brakes on all four corners. As another example.
When looking for axles to buy. It is easier to buy the axles you want under the truck as is. Then pick and choose all the goodies you plan on putting inside them separately. IMHO, But my opinion isn't that valuable.

And like SandKing said... Lets see a picture of this blazer!
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Old 04-07-2011, 07:17 PM   #13
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Re: front and rear end gears??

I run a 383/th350 with 33"s and 4.10 myt truck is a bit heavy cause of the tubing and stuff but it drives ok on the road although at high speeds people say it does sound loud like it needs one more gear... so you might be ok with the 4.27's cause you kill the 350 tranny at high speeds.
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Old 04-07-2011, 07:23 PM   #14
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Re: front and rear end gears??

Have you considered a 700r4? It's a 4 speed overdrive automatic.
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Old 04-07-2011, 08:06 PM   #15
dave666693
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Re: front and rear end gears??

I have 4.10's in my 3/4 ton pick-up with 31" tires. It has a strong 350. At 65 it drives fine. I am guessing 4:10's is the way I will go with some kinf of limited slip in the rear and a locker in the front. I have a good deal available for a front and rear end with 3:73's, but the 35" tires would be a problem I think.
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Old 04-07-2011, 10:03 PM   #16
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Re: front and rear end gears??

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Originally Posted by dave666693 View Post
I have 4.10's in my 3/4 ton pick-up with 31" tires. It has a strong 350. At 65 it drives fine. I am guessing 4:10's is the way I will go with some kinf of limited slip in the rear and a locker in the front. I have a good deal available for a front and rear end with 3:73's, but the 35" tires would be a problem I think.
Wouldnt it be the other way around, locker in the rear and a limited slip up front...
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