I finally had my 3.90 gears and Eaton installed today. I had dropped my truck off at the performance shop here in town (B&M Performance) yesterday at about 4:00 and took my computer out. This morning my sister drove me to Walker, LA (4 hour drive) to Futral Motorsports to have my computer tuned for the gears. While I was down there, Candy showed me the new shop, it was awesome! I also got some info and advice from Allan on my 383 LS1 build up. Thanks for everything FMS!

When we got back, put the computer in the truck and drove it for about 10 miles to my house. It drives really good, shifts alot more than it used to, but I kinda like it. I listened for a whining noise coming from the gears. I could Barely hear a very, very slight whining sound (windows up and stereo off) at about 57-62mph. Besides that, it is dead silent. If you didn't know what to listen for, you probably wouldn't hear it at all.

So far I've driven it twice since the gear install, I've been babying it. After about the 5th or 6th time, I'm gonna try it from a roll and see what she's got and let ya'll know how it goes.

 

I tried calling you last night to see how it went. What did they say about your detonation & lean condition? I was wanting to get with you one night & drive out to the GM Blvd. , Joey & I went monday night & made a couple of passes. It was a wonderfull site!

 

I hope you have better luck than me. I've got 700 bucks in my rearend and I'm back to 3.42 and open diff. My gears were not set up properly and I am not a happy camper.

 

M.Roberts who did your gears? B&M didnt did they???????????????
Richard----Im gonna say one thing--------You should have just got 4.10's!!!!

 

Micheal----I'm gonna say one thing-------You should have got a 5.3!!!! J/K dude! The reason I wanted the 3.90's, is for my 383 setup later down the road. I know you like the 4.10's, but for me it's too much gear

 

Im gonna say one thing as well LQ9!!!!!!!!!!!!

 

Well, after the constant mental abuse of not seeing what my gears would do, after about the 5th or 6th break-in cycle, I did it. The first time I got on it, I was going 40mph (which with the 3.42s was a flat spot), the speedo hit 55mph really fast. The next time, I was going 70mph (which the rpms are now right at 2100), and I reached 90mph suprisingly quick. I can't believe how good 3rd gear pulls now! The last time I tried it out from about a 10mph roll, it pulls like a rocket compared to before! I am extremely pleased with the performance of the 3.90s. Anybody that has the 3.42s doesn't know what they're missing!

 

Alan is the man when it comes to ls1 anything. I hope to be making a trip down there in the near future. Glad to hear you like the 3.90 gear.

 

I agree! Thanks!

 

Some more info about the 3.90s:

With the 3.42s I was shifting at these: 1-2 @ 50mph and the 2-3 @ 93mph. The shift points were set at 5900. With the 3.90s I'm shifting at these: 1-2 @ 44mph and the 2-3 @ 82mph. The shift points are now at 6000-6100.

I really don't feel like I lost too much of the top-end. If I was to race a truck set-up exactly like mine before the gears, I would pull it real hard until about 82mph. Then it would gain until it hit 93mph. After that I would pull and still beat it. This is a kinda goofy example, but Ya'll know what I'm saying!

The shifts are way harder than they were before. Used to the 1-2 shift would chirp every now and then. Now it spins and goes to the side a few inches. The 2-3 shift is a whole lot faster and harder as well.