TheAMCForum.com Homepage
Forum Home Forum Home > Competition > Jeeps and Eagle 4x4 fun.
  New Posts New Posts RSS Feed - J10 headers? For 3in exhaust?
  FAQ FAQ  Forum Search   Events   Register Register  Login Login

Click for TheAMCForum Rules / Click for PDF version of Forum Rules
Your donations help keep this valuable resource free and growing. Thank you.

J10 headers? For 3in exhaust?

 Post Reply Post Reply Page  12>
Author
Message
amc401t10 View Drop Down
AMC Addicted
AMC Addicted
Avatar

Joined: Mar/09/2009
Location: east tn
Status: Offline
Points: 903
Post Options Post Options   Thanks (0) Thanks(0)   Quote amc401t10 Quote  Post ReplyReply Direct Link To This Post Topic: J10 headers? For 3in exhaust?
    Posted: May/09/2020 at 10:43am
I crashed my hot rod, gremlin x, 550 hp 401. Putting the 401 in my 82 j10.
Gotta have 3in exhaust! My long tube headmans exit so close to frame and Tranny, 
I don't think they can fab 3in to attach? Was thinking shorty headers might work?
Anyone got 3in, or even 2.5 in duals from headers?
My current 360 exits through 2in. Dumps in front of rear wheels.
Help?

1-owner 74 gremlin x 401, t10,3.73 12 bolt,750carb,reed 250@50 cam, roller rockers,msd,offy int.
72 amc matador 401 727
84 j10 ,360, 727
1970 4-door rebel sleeper(455 pontiac,turbo 400)
79 spirit,4.2
Back to Top
BrotherBamc View Drop Down
Supporter of TheAMCForum
Supporter of TheAMCForum
Avatar

Joined: Jan/22/2009
Location: Lewiston
Status: Offline
Points: 2248
Post Options Post Options   Thanks (0) Thanks(0)   Quote BrotherBamc Quote  Post ReplyReply Direct Link To This Post Posted: May/09/2020 at 12:25pm
You shouldn't have any problems with a 3 inch exhaust on your J-10. I think it all depends on the skill level of your exhaust guy.
I just had 2 1/2" pipe from collector all the way back in my Gremlin. We did have to cut part of the bolt on collector off to get the 2 1/2" pipe to hook up, but my exhaust guy did it.



77 CJ5 360
73 Gremlin 401 4 speed
2006 Dodge Magnum R/T AWD
My Garage
Back to Top
amc401t10 View Drop Down
AMC Addicted
AMC Addicted
Avatar

Joined: Mar/09/2009
Location: east tn
Status: Offline
Points: 903
Post Options Post Options   Thanks (0) Thanks(0)   Quote amc401t10 Quote  Post ReplyReply Direct Link To This Post Posted: May/10/2020 at 11:01am
I went from 2.5in to 3 in on my gremlin, couldn't get over rear end, so turned down in 
front of rear.felt like another 100 HP above 4000 rpm! But damn it was loud!
On the j10 the collector exits right by the frame rail and crossmember . Theirs wires and fuel and brake
Lines in their. The 2in fits with only limited clearence on each side.
I thought maybe with the shorty header I could go under the crossmember? 
Ps what powers that gremlin?
1-owner 74 gremlin x 401, t10,3.73 12 bolt,750carb,reed 250@50 cam, roller rockers,msd,offy int.
72 amc matador 401 727
84 j10 ,360, 727
1970 4-door rebel sleeper(455 pontiac,turbo 400)
79 spirit,4.2
Back to Top
BrotherBamc View Drop Down
Supporter of TheAMCForum
Supporter of TheAMCForum
Avatar

Joined: Jan/22/2009
Location: Lewiston
Status: Offline
Points: 2248
Post Options Post Options   Thanks (0) Thanks(0)   Quote BrotherBamc Quote  Post ReplyReply Direct Link To This Post Posted: May/10/2020 at 11:20am
I consider it a mildly built 401.
.30 over, comp 280ish cam, speedpro 27 dished forged pistons, moly rings, 750 double pump Holley, stock 993 heads, Mallory unilite, MSD 6al ignition box, Comp cam roller rockers, hooker super comp headers, RobbMc mechanical fuel pump and an old school, carb cooking, torker intake with a 1 inch spacer..

77 CJ5 360
73 Gremlin 401 4 speed
2006 Dodge Magnum R/T AWD
My Garage
Back to Top
BrotherBamc View Drop Down
Supporter of TheAMCForum
Supporter of TheAMCForum
Avatar

Joined: Jan/22/2009
Location: Lewiston
Status: Offline
Points: 2248
Post Options Post Options   Thanks (0) Thanks(0)   Quote BrotherBamc Quote  Post ReplyReply Direct Link To This Post Posted: May/10/2020 at 11:24am
77 CJ5 360
73 Gremlin 401 4 speed
2006 Dodge Magnum R/T AWD
My Garage
Back to Top
amc401t10 View Drop Down
AMC Addicted
AMC Addicted
Avatar

Joined: Mar/09/2009
Location: east tn
Status: Offline
Points: 903
Post Options Post Options   Thanks (0) Thanks(0)   Quote amc401t10 Quote  Post ReplyReply Direct Link To This Post Posted: May/12/2020 at 11:24am
Makes me miss mine, it was my 1st car, 74 X with 304. 
10 years later it was a 401, T10, 3.73 12 bolt. 500 HP
It was a hand full! Only AMC in my area that got respect.
I'd run anything! Got beat a few times.
But surprised a Whole lot of other brands!
The good old days!
1-owner 74 gremlin x 401, t10,3.73 12 bolt,750carb,reed 250@50 cam, roller rockers,msd,offy int.
72 amc matador 401 727
84 j10 ,360, 727
1970 4-door rebel sleeper(455 pontiac,turbo 400)
79 spirit,4.2
Back to Top
fastjeep View Drop Down
AMC Fan
AMC Fan
Avatar

Joined: May/22/2011
Location: York PA
Status: Offline
Points: 23
Post Options Post Options   Thanks (0) Thanks(0)   Quote fastjeep Quote  Post ReplyReply Direct Link To This Post Posted: May/28/2020 at 11:07pm
Have a 86 J10 with the shorty headers ,i made a 2.5 Y pipe to right side. Used a Flowmaster 2.5 to 3 merge pipe then ran 3 from there. With flowmaster muffler it sounds good. We in PA there always threating to go after modified exhaust ( all the coal burners and their stacks ) this looks like stock pipe. I know since put on Fitech injection it really sounds good. Used the early left side header with rear exit and with 4" lift no clearence problems with drivers drop pumpkin.  
Back to Top
Jmerican View Drop Down
AMC Addicted
AMC Addicted
Avatar

Joined: Mar/29/2016
Location: Seattle, Wa
Status: Offline
Points: 585
Post Options Post Options   Thanks (0) Thanks(0)   Quote Jmerican Quote  Post ReplyReply Direct Link To This Post Posted: May/30/2020 at 12:57am
The exact parts fastjeep is describing make for an excellent FSJ 360  exhaust, with all mandrel bent pieces of course. The collector is a key piece. 
Back to Top
amc401t10 View Drop Down
AMC Addicted
AMC Addicted
Avatar

Joined: Mar/09/2009
Location: east tn
Status: Offline
Points: 903
Post Options Post Options   Thanks (0) Thanks(0)   Quote amc401t10 Quote  Post ReplyReply Direct Link To This Post Posted: Jun/07/2020 at 12:51pm
Fastjeep,  got any pics. 
I've benn looking under mine, (I need the long tube(ceramic coated) headers to take advantage of the 500hp), I'm thinking 2.5 to mufflers then 3 out? Their might be room for 2.5 above the crossmember, 1 down ea side, if I move my wires,   if not room, I'll run the Dr side over and down the pass side .  Pilenty of room on pass side.
 Again , I drove this engine in my car with 2.5, turbo mufflers, and thought it was awesome!  Then went to 3in, with flowmasters, felt like another 100hp, above 3500 rpm!
Thanks for all the ideas!
1-owner 74 gremlin x 401, t10,3.73 12 bolt,750carb,reed 250@50 cam, roller rockers,msd,offy int.
72 amc matador 401 727
84 j10 ,360, 727
1970 4-door rebel sleeper(455 pontiac,turbo 400)
79 spirit,4.2
Back to Top
Heavy 488 View Drop Down
AMC Addicted
AMC Addicted


Joined: Apr/27/2019
Location: In the
Status: Offline
Points: 3529
Post Options Post Options   Thanks (0) Thanks(0)   Quote Heavy 488 Quote  Post ReplyReply Direct Link To This Post Posted: Jun/07/2020 at 2:41pm
Felt like another 100 horse or at least sounded like it? LOL
Back to Top
 Post Reply Post Reply Page  12>
  Share Topic   

Forum Jump Forum Permissions View Drop Down

Forum Software by Web Wiz Forums® version 12.03
Copyright ©2001-2019 Web Wiz Ltd.

This page was generated in 1.688 seconds.
All content of this site Copyright © 2018 TheAMCForum unless otherwise noted, all rights reserved.
PROBLEMS LOGGING IN or REGISTERING:
If you have problems logging in or registering, then please contact a Moderator or