Hey all, considering having a local shop upgrade to support the new 470 build. It is the original rear for a 350 2 barrel. I know some members can build 12 bolts and send them. Any recommendations? jr
Have @BrianTrick build your original 8.5 if you can send/take it to him or buy one from him already built. No need for a 12 bolt.
I can build whatever. The 71-72 8.5” is a great rear to build and US Gear makes 3:55’s for them. I’ve built six or seven 8.5’s with those gears and they are a quality set.
I might. The first thing is to check on shipping. I like to use Fastenal,but they have recently limited some of the areas and regions where they will ship to.
If you're going to do any highway driving I would recommend a 3:23 or 3:08 gear in the back. I have run many different gears over the years and my favorite gear is the 3:23 for a mix of highway and fun. If you're going to race it then thats a whole different story.
Actually,Fastenal started more restrictions at the end of 2022. I think Georgia was one of the places where I could ship before,but now I can’t. Even some in Indiana. I’ve just made a point to find out first before going ahead with the build.
Punch yourself in the balls 10x and burn a couple grand.. skip that turd and get a 4l80, especially with a 470.
Joe, don't you have to modify the tunnel with a 4L80? I went with the 200R because I was told it would not fit without modification? BTW, I have no issues with my tranny, it is spot on.
If your body mounts are in good shape then no cutting is required. A whack or two with a hammer is the worst of it, and many just fit.. The cost of the 4l80 is maybe just a little more, but it is 10x the trans than the 200 will ever be.
A 3.73 gear set with a 28" tire (P275/60R-15 as an example) is effectively, a 3.55 ratio. Put a 26" Drag Radial (P275/50R-15 as an example) gives you a 3.82 ratio for the drag strip. Just sayin. The 2004R has a .67 OD gear. You can go higher than a 3.55. The 3.73 will reduce to 3.73 X .67 = 2.499 final drive.
I’m sure my body mounts are garbage. Similar to most of the other 50+ year old rubber I’ve already replaced. Also, already ordered a 200 from CPT.
I still run TH400’s,but my friends and customers that I know that are running overdrives are running the 2004R,and plenty of them are behind some serious builds. It’s a 1/2” longer than a TH350.
In all seriousness you should plan on replacing the body mounts. You'll need the rigidity with more power.
This can easily snowball into a larger project,BUT if you are going to have the rear out of the car,or at least back there addressing that area,I highly sugggest staying back there and focusing on everything at the rear suspension. Axle rebuild,aftermarket upper/lower control arms with something other than rubber bushings,upgrades springs & shocks,and a rear sway bar(preferably thicker than stock).
