Your donations help keep this valuable resource free and growing. Thank you.
|
Model 20 Strength |
Post Reply | Page 12> |
Author | |
scramboy
AMC Nut Joined: Apr/12/2009 Location: new york Status: Offline Points: 456 |
Post Options
Thanks(0)
Posted: Nov/27/2017 at 8:58am |
Have a modified model 20 in my Scrambler, Henrys axles, Detroit Locker, welded tubes, super reinforced spring pads, Richmond 4.56 gears, etc. I have a 550+ hp motor going in this winter potentially shooting for 10 sec times. Will the mentioned model 20 live? I dumed a bundle of $ into it and it fits great I hope I won't have to go to a 9in. Any opinions will ease my mind. Thanx Scramboy.
|
|
304-dude
AMC Addicted Joined: Sep/29/2008 Location: Central Illinoi Status: Offline Points: 9082 |
Post Options
Thanks(0)
|
550+ hp should do fine. It's when you get passed 700+ it starts to have issues. I think the caps will give up before anything else.
|
|
71 Javelin SST body
390 69 crank, 70 block & heads NASCAR SB2 rods & pistons 78 Jeep TH400 w/ 2.76 Low 50/50 Ford-AMC Suspension 79 F150 rear & 8.8 axles Ford Racing 3.25 gears & 9" /w Detroit locker |
|
tufcj
Supporter of TheAMCForum Supporter of TheAMCForum Joined: Jul/10/2007 Location: Watkins, CO Status: Offline Points: 4086 |
Post Options
Thanks(0)
|
The biggest weaknesses in the Model 20 are the tube welds, spring pads and 2 piece axle shafts. I think you've addressed about all of the weaknesses. The only thing you didn't mention was replacing the crush sleeve with a solid spacer and shims. That stabilizes the pinion bearing preload. The ring gear is 8 7/8" diameter, only 1/8" smaller than a 9", bigger than a Dana 44 or Ford 8.8. It should hold 550 HP without a problem with the mods you've made.
Bob tufcj |
|
69 AMX
74 Javelin AMX 67 Rogue If you need a tool and don't buy it... you'll eventually pay for it... and not have it. Henry Ford |
|
Cricket
AMC Addicted Joined: Jul/06/2015 Location: Milton, FL. Status: Offline Points: 736 |
Post Options
Thanks(0)
|
Naah, way to weak, sell me yours for 50 bucks, and just go full tilt bogey with a 9 inch Fraud rear!
Cricket |
|
jpnjim
AMC Addicted Joined: Nov/25/2007 Location: New England Status: Offline Points: 2752 |
Post Options
Thanks(0)
|
If the crush spacer is gone, I'd just keep an eye on it as the power and traction ramp up. With enough of traction, the thin axle tubes and 8 lonely ring gear bolts would probably be the first to complain |
|
71 P-code 4spd Javelin/AMX
some Jeeps and some Fords |
|
ttrrogg
AMC Apprentice Joined: Jul/21/2012 Location: torrington, ct Status: Offline Points: 240 |
Post Options
Thanks(0)
|
A dana 20 is an 8 7/8 inch rear about the same as a 9 inch ford. If you change the the axles you should have no problems. Been there done that for 500hp.
|
|
1970 Big Bad Blue javelin sst
|
|
SC397
AMC Addicted Joined: Apr/30/2009 Location: Michigan Status: Offline Points: 5476 |
Post Options
Thanks(0)
|
The Dana 20 is a Transfer Case.
The AMC Model 20 Axle has been around since the '50's. A very strong unit with the modifications that you have made. I say drive it like you stole it! |
|
DaemonForce
AMC Addicted Joined: Jul/05/2012 Location: Olympia, WA Status: Offline Points: 1070 |
Post Options
Thanks(0)
|
In the case of wheeling, would it make more sense to rely on a deep geared Model 20 or Dana 44? Would the axle still be the mechanical fuse in that setup @2.72 or 3.08 gearing? I've always had questions about the Model 20 axle and can never find it. I think it's my actual go to preference because it would be a drop-in swap but I'm also curious about the 44.
|
|
1971 Javelin SST
American 304 2v | FMX | AM20-3.31 1983 American Limited Jeep 4(.7)L S-MPFI | 1982 NWC T-5M (4.03/.76) | Dana30IFS/35-2.72 |
|
shootist
AMC Addicted Joined: May/24/2012 Location: Triad, NC Status: Offline Points: 1023 |
Post Options
Thanks(0)
|
I run a 9" in mine but I am also well up there in power these days. I wouldn't bat an eye to put 700 hp through a model 20 with a few options to beef it up. Weld the tubes, change to solid axles and maybe even add a truss if you are worried that much but that is not as vital or as beneficial in a drag application.
|
|
|
|
tufcj
Supporter of TheAMCForum Supporter of TheAMCForum Joined: Jul/10/2007 Location: Watkins, CO Status: Offline Points: 4086 |
Post Options
Thanks(0)
|
What size tires are you running? 2.72 or 3.08 on the trail would be terrible with anything but 26" street tires. I spun a couple of 2 piece AMC 20 axles with 35" tires on my CJ. I went to a Dana 44 rear before 1 piece axles were available for the 20. The 44 held up fine, the axle shafts in the Dana 30 front became the weak link. When I went to 37" tires, I upgraded to Dana 60 rear and 44 front, never broke another axle. The U-joints in the driveshafts became the weak link. I ran 3.73s in the AMC20, ran 4.27s in the 44. I went to 4.88s with the 37s. Bob tufcj |
|
69 AMX
74 Javelin AMX 67 Rogue If you need a tool and don't buy it... you'll eventually pay for it... and not have it. Henry Ford |
|
Post Reply | Page 12> |
Tweet
|
Forum Jump | Forum Permissions You cannot post new topics in this forum You cannot reply to topics in this forum You cannot delete your posts in this forum You cannot edit your posts in this forum You cannot create polls in this forum You cannot vote in polls in this forum |