Ls swapped rear end question
 

Hey fellas, new to the site have a 1967 C10 I've been building for quite some time, stock chassis, carb'd 6.0 ls lq9, stock crank and rods, hyperutetic pistons @ 10.5:1 comp, ARP bottom end, 229/236 cam on a 108 lsa with the ls3 heads, runnin a single plain intake. Engine dynoed at 556 hp at 6500 rpm.. M21 trans, currently has 3:08 but I want somethin a bit peppier. Truck mostly will be driven around town and taken to the track every now and then. Wondering what you guys would recommend for a rear end gear, 3:73 or a 4:10. Truck has 29x18.5 Mickey Thompsons, any input is appreciated!!
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Re: Ls swapped rear end question
 

That engine will love the 4:10's, but not sure how much the transmission will help on the freeways. 3.73's would certainly make it peppier, and still do good at highway speeds.

I run 4:10 in my carbed LS1 with a similar cam, but I'm using a 700R4 with overdrive.

Re: Ls swapped rear end question
 

My 6.0 with 4l80e over drive the 4:10 are good.:chevy:

Re: Ls swapped rear end question
 

I like 3.73 for the street unless it is a 4x4 with big tires.

Re: Ls swapped rear end question
 

4.10s here with a 4L80E (overdrive), it's about right. Lots of gear in town. I wouldn't go much more than 3.55 or at most 3.73 without overdrive though. Just me.

Re: Ls swapped rear end question
 

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Unfortunately the M21 is a standard car 4 speed with no OD so 4.10's would be a bit low. The 3.73 would work great for that application and that is what I would recommend.....

Just my 2¢ worth.

LockDoc

Re: Ls swapped rear end question
 

I have 3.73's with a 29" tire and a 4l60e. I think its perfect. Stock LS1, though, and I already cant get any rear traction:chevy:.

Depends on how much time you plan on spending at the track. I'd go 3.73's with or without O/D but my truck is much more about just enjoying the cruise these days.

Re: Ls swapped rear end question
 

With 556hp on tap I think a 3:55 would be a good setup. Your gonna have a hard time not blowing the tires off regardless of your gearing, but the deeper you go the less traction you're gonna have.

Re: Ls swapped rear end question
 

X5 on 3.73, if the trans had OD I might go 4.10

Re: Ls swapped rear end question
 

Having raced a manual trans for several years now...for the track you'll want a 4.30 or 4.56. But since that's obviously pretty terrible for the street, just go with a 3.73 and have fun. Getting outta the hole with a clutch and sticky tires isn't easy!

Re: Ls swapped rear end question
 

Agree , plus most of these trucks came with that gear , you'll want a posi