I'm currently building my 422 that will be finished in about 2-3 weeks. I ended up with some extra cash and wanted your opinions on up-grading my diffs. Right now all I have are stock 3.73's w/ power trax locking spider gears. I'm thinking about going with an Eaton setup but wanted your opinions on keeping the 3.73's or going for 4.10's. This is what my set up will be when it's all done:
422-4.030" bore 4.125" stroke all forged Lunati rotating assembly
Stage III 6.0 heads- 2.100"in 1.600" ex w/ dual springs
Match ported truck intake
Comp 246/246 600/600 110LS
FLP level IV 4L65E
Yank 3000
Dynatech Long Tube headers w/high flow cats
42# injectors

I use my truck as a daily driver and don't do much towing. My driving is about 60% city and 40% highway. I'm also thinking about a 200 wet shot later this summer. I know if I raise my gear ratio I'd have to up my front diff also. Thanks for any help.

 

i dont think you need the gears unless you plan on running some 33" tire or bigger. i have heard some bad things about the power trax and would agree it should be upgraded. i don't see that tranny lasting long once you start spraying.

only thing i see that seems a little out of wack is you cam choice, i don't know alot about cams so some other oponions here would be nice but that is a prety big cam, the long stroke 422 is a torque monster that might not want to be reved to the moon. see if you can get some more input on that part of your plan.

 

who did the machine work on the block etc? did they clearance the block for the longer stroke to clear the rod bolts? i noticed on mine that there wont be much room for clearance once the big stroke is in there. thanks

 

I was originally going to go with MTI's recommended cam, a 242/242 595/595 112LS but was told by ARE and Nasty Performance that it was a pretty mild cam for the set up I have. Nasty Performance is doing my heads, when I asked for their advice they suggested a custom comp cam with those spec. FLP also took all this into consideration when they recommended the 4L65E up-grade. But thanks for your input on the gears. I am presently running 33's but, will go back to stock size when it's ready run again.

Slowverado-The block is being machined right now so I'm not sure what all machining is needed. I'll let you know as soon as I find out.

 

Talk to Wade at ARE. We ended up with a mild 228/228 .573 112 in the Escalade 423. Let me say, it is still a large cam. Yes, the extra cubes eat up the cam, but its still big. Parish8 is right, the bigger the cam, the higher the rpms peak power shows up. I would try and keep the duration numbers down, so the power stays down in a useable range. It doesn't matter that much to a light weight trailer queen car, but for a heavy truck thats daily driven, keep the rpms down. You don't want to have to spin 7K to get the power out of it.

I'd be tempted to go to 4.10s. You don't really need the extra torque multiplier, but the goal should be to end up at the end of 3rd gear in the 1/4 mile. That could be mid 11x MPH. If you have lots of hard miles on the stock gears, you might as well do it.

 

with the stock tires (32"?) i had it up to 136mph, i think i could have hit 140 by 6100rpm. i like what you are saying about gearing it to just barely stay in 3rd, if thats the case could he go steeper than 411? and what are the consiquinces besides higher rpms and worse miliage, what parts would it put more stress on if any? or would it lighten the load on some of the driveline?

 

It should take stress off the drivetrain since its adding to the mechanical advantage of the motor. Going to 4.10s would give a 10% multiplcation effect.

 

When I was speaking to the techs at Nasty Performance, I told them that I didn't want to rev any higher than 6500 RPM's. That's still pretty high, I know but, they explained that bringing the lobe seperation down to 110 would also bring down the powerband of this cam. I've spoken to several other f-body guys and they've actually suggested a cam in the 248/254 range. Everyone I've spoken to knows that this set up is going into a 5000+lb truck. Nasty Performance actually has asked me to bring my truck to them to test their new sheet metal intake and see some dyno results. I must admit that I hardly know anything about cam choices but, I also think I need to trust the guys that are going out of their way and investing their own time and money to get my truck right. I don't mean to bash you guys in way, I've highly respected your opinions from day one. Now back to my original question, 4.10's do seem to be a smart investment? Again, thanks for all the help.

 

Id go with the 4.10s. If you are planning on putting real lockers in there anyways, you will be rebuilding the entire diff anyways. Also if you dont do a full carrier locker, you can just put some smaller tires on there to effectively give you a steeper gear ratio.

Also your drivetrain will have less stress on it with lower gears, except for your gears, carrier, and axles. Everything after the Pinion gear will effectively see about 10% more stress, basically anyways.

Do a little math and see what speed you would be maxing out at, and if you can, go to the lower gear