Hey guys, after all the blood,sweat and tears...the ol 401 finally came alive this past weekend. The wiring problem I was having was simply fixed and the flexplate I had to get balanced works like a charm. I do have a few quick questions though. Are the drum brakes able to be adjusted so the frt actually feels like they work or is this a commando characteristic-"this jeep gets going fast real quick" but stopping takes a while! I don't really want to get into another swap for awhile. Also I need to redo the exhaust -they are currently garbage and they go from the exhaust manifolds to under the rockers with side exit on each side. I am wanting some input on the size exhaust to redo and what types of mufflers to put on it without causing hearing loss. Any input on these two things would be awesome. Thanks again for all the help with this beast! Nate
401 SWAP IS FINALLY RUNNING
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congrats on getting the 401 running.
i have done the same swap to my H/C. i'm going to assume you have a bullnose in
witch you have 11'' drums. although there is nothing like disc breaks, the drum units
are more than adequate when working properly. they are very simple, easy to work
on and parts are readily available. i prefer manual breaks and although it's on my list,
i have not had a need or desire to convert to disc. btw, almost all commandos lock
up the pass side rear tire first, i know not why, but even read an old road test on one and they complained of the same thing
as far as the exhaust, it sounds like it's already run to a perfect location. i run dual
exhaust down from the manifolds under the frame, behind the spring hanger along the
out side of the frame, using 30'' cherry bombs, out in front of the tire. it's surprising
how quite it is, but yet it has a nice low rumble.
i have done the same swap to my H/C. i'm going to assume you have a bullnose in
witch you have 11'' drums. although there is nothing like disc breaks, the drum units
are more than adequate when working properly. they are very simple, easy to work
on and parts are readily available. i prefer manual breaks and although it's on my list,
i have not had a need or desire to convert to disc. btw, almost all commandos lock
up the pass side rear tire first, i know not why, but even read an old road test on one and they complained of the same thing
as far as the exhaust, it sounds like it's already run to a perfect location. i run dual
exhaust down from the manifolds under the frame, behind the spring hanger along the
out side of the frame, using 30'' cherry bombs, out in front of the tire. it's surprising
how quite it is, but yet it has a nice low rumble.
Congrats Nate,
Yes the drum brakes can and should be adjusted. This will help with the stopping, especially if the shoes on one end are further off the drum than the other. There is a star wheel adjuster between the pads near the bottom. It should adjust itself, but I always check mine (from back in my race car days, when I tried to eliminate any extra drag). To get the wheels even, I usually adjust each one until the shoes drag a bit, then back it off until it just spins free. I'm not a mechanic, but that method has always worked for me.
I have factory 11" drum power brakes on my 73 with a 304. I don't run big tires, and it will lock the wheels up if I stomp on the brakes (like when the deer ran out in front of me). It stops fine.
I too just got my 401 running (in the unfinished project Commando I recently bought). That thing has 2" dual exhausts that exit the rear, and it is just as loud in the cab as the 304, which has a 2 1/4" exhaust that exits in front of the rear wheels. The mufflers are similar turbo style, and are basically in the same location under the front seats. So for my jeeps it doesn't make much of a difference with the routing.
I guess I'm getting to be a wus in my old age, but that 401 is way more motor than I want in that skinny old jeep. That thing is scary to drive.
Yes the drum brakes can and should be adjusted. This will help with the stopping, especially if the shoes on one end are further off the drum than the other. There is a star wheel adjuster between the pads near the bottom. It should adjust itself, but I always check mine (from back in my race car days, when I tried to eliminate any extra drag). To get the wheels even, I usually adjust each one until the shoes drag a bit, then back it off until it just spins free. I'm not a mechanic, but that method has always worked for me.
I have factory 11" drum power brakes on my 73 with a 304. I don't run big tires, and it will lock the wheels up if I stomp on the brakes (like when the deer ran out in front of me). It stops fine.
I too just got my 401 running (in the unfinished project Commando I recently bought). That thing has 2" dual exhausts that exit the rear, and it is just as loud in the cab as the 304, which has a 2 1/4" exhaust that exits in front of the rear wheels. The mufflers are similar turbo style, and are basically in the same location under the front seats. So for my jeeps it doesn't make much of a difference with the routing.
I guess I'm getting to be a wus in my old age, but that 401 is way more motor than I want in that skinny old jeep. That thing is scary to drive.
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1,249 Posts
Glad to hear its running Nate, you can adjust the drums so they work better but I will second or third the recommendation for the disc upgrade, its really quite easy to do and is well worth it, you can even get complete kits from a few places for a fairly decent price if you don't want to mess with making things fit. The first exhaust I made for my 72 with a 360 went from the manifolds to some 2 or 2 1/4 inch pipe which went outside the frame rail right behind the front spring hanger then to a pair of Cherry Bombs and it exited right past the rocker in front of the rear tire. It was okay but it did get loud especially on the highway so I eventually swapped to a pair of turbo mufflers and some new pipe but kept the exit location the same. It is a little better and the tone is not as abrasive as the Cherry Bombs but honestly its still pretty loud. It doesnt really bother me but occasionally a passenger (the wife) will complain. I have thought about adding one of those tips that disrupts the flow and quiets it down a bit but it hasn't happened yet. I would say you could stick with 2 1/4 inch pipe and have plenty of power and I have seen pics on here of a system that runs outside the frame rail and exits out the back that seemed to work pretty well and not interfere with anything: gas tank, springs, shocks, etc... but I'm not sure who's it was?
Properly working 4-wheel drum brakes should be adequate. RRich preaches the importance of the drums being true and placed on the hub properly, and he is right. ( Yes, here I go again..) My '71 Road Runner bracket car runs 11:40 quarters and I have no trouble stopping it at all with 11x2.5 manual drums all of the way around. And it weighs 4300# with me in it. I believe that the big disadvantage of 4-wheel drums on a jeep isn't in the inability to stop, its in getting mud in the drums and not being able to stop from that.
I have a question about exhaust also. Do you need a crossover pipe between the two exhaust pipes. and what is the purpose of it. I was told several years ago that the reason my turbo mufflers were only lasting about a year on my waggy was because I didn't have a crossover pipe.
Thanks for all the feedback guys. I figured that there was a way to adjust the fronts just like the back. The cherry bombs toad referred to -are they the ones that I saw at my local Checker auto parts store for like 17.00 bucks apiece?Thanks again, Nate
A cross-over or "x" pipe helps to equalize pressures and there are people who swear by them for increases in torque. As to your turbo-type mufflers, I guess it is remotely possible that, if they were blowing out, a crossover might drop peak pressure a bit. Most likely they were just pinched together to seal them anyway.
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5,472 Posts
Probably so. I know the glasspacks on the Moss are stinkin deathening at highway speeds (combined with the Swampers). They came from a JCW "258 dual exhaust" kit and were free so I can't knock'em too bad. Besides, if I wanted it sound like a sewing machine, I'd have bought one!
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BTW, congrats on getting it to fire!
BTW, congrats on getting it to fire!
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