- City
- Kingman
- State
- Ks
This will probably be longer than I want it to be, but figure the back story is relevant. My Scrambler has gone from 151 Iron Duke, to a Buick 231, to an AMC304 over its life. The Buick to AMC304 I did because the SR4 transmission wouldn't stay in reverse and I was tired of it. I wanted to go to an NP435. When I went to swap it out the transmission tower was going to force me to cut my tub or move the motor back. I didn't want to deal with re-positioning the motor when I wanted a V8 anyway and I refused to cut my tub. My dad had the AMC304 rebuilt from a wrecked jeep back in the early to mid 90's. It sat on an engine stand wrapped in plastic and covered with a blanket until 2014 or so when I resurrected it. It had never been ran until I put it in the Jeep. I broke the cam in the way they say with comp break in oil, and drove it highway as much as I could to vary the RPM. It seemed to run okay and didn't have any really problems for the 1st year, other than it would drink oil if you ran it down the highway, but wouldn't smoke.
3 years ago I added FITech efi to it when I changed axles and suspension out. We went to Colorado after I got it done. After sustained RPM's up a mountain pass it developed an oil leak. I have fought that since that point up to a few months ago. Can drive around town and crawl for days and dry, but run it at highway speeds or sustained RPM for more than 40 min, oil everywhere. I resealed my intake, front cover, did some DUI distributor mods and got it to stop leaking after driving 50 miles at sustained rpm. Thought maybe I had won. We went back to Colorado this past month and on the way home I lost a trailer wheel bearing, and was forced to drive the jeep the remaining 430 miles, as I didn't think i could get the trailer fixed. Each gas stop, which was often, I looked for the oil leak to show up, which stayed dry all week on our trip. I made it about 380 miles before it started dripping. It is still much better than before, other than it took a quart of oil to travel home. It doesn't smoke that I can tell and has okay power as long as your not at altitude. I need to do a compression check, but I am to the point I believe the rings didn't seal or are stuck, the cylinders are glazed making crank pressure (PCV has been checked repeatedly), or I still have an intake issue. If either of cylinder thoughts are true then I have to tear it down. If it has to come out I don't want to put it back in.
I have an AMC401 on a stand that I could tear down and go through to see what it takes to rebuild, or I could find an LS.
I have been following this thread, but didn't want to hijack it as it had good info for what he was looking for. Posts 23,24,25 provided me some good info.
https://www.cj-8.com/threads/amc-360-build.48836/page-2#post-404027
I also read through this older thread and it had mixed opinions and seemed like the 401 was the choice to do.
https://www.cj-8.com/threads/opinions-on-engine.37289/
I know the 401 is going to cost $ to rebuild even if I don't have to do machine work and can get away with just pistons, bearings, cam, new timing cover, oil pump etc. Locally around KS am I not sure where I would take it to have work done. The Jerry Tucker post from the thread above was informative, but a long ways from KS. With the 401 I have to change nothing with my current setup, just put the motor together and it goes in the jeep. I already have EFI that works okay, hoping it will work better if the motor doesn't have possible internal issues. The LS I have to find, have harness work done, redo motor mounts, bellhousing to NP435, redo clutch setup, exhaust, probably have to do electric fans as well. Although the motor part of an LS swap using a 5.3 or 6.0 with a cam swap would be cheaper, the external items add up. I have not priced everything, but I can guess it would offset the cost vs the 401. The LS would maybe get better fuel mileage (better than 10 I get now?), would be more reliable, leak less oil in time, probably last longer, and probably make enough power to make me happy. As I understand from research the 401 should make more torque across the rpm band vs the LS until the upper RPM's which would be nice on a trail or just off idle. The 401 would also make enough power to make me happy and the exhaust note too.
I do a little of everything highway, around town, Colorado trails, semi local rock parks, and sand dunes. It would be nice to be able to drive the heep across country, but will probably continue to haul it. I am kind of stuck on what to do. The more I read and research the more I think going with the 401 is the best route. If I didn't have it the choice would be easier.
Anyone have thoughts on which route to go?
Anyone gone from a 360 or 401 to LS or vice versa? What did you like or not would you do it again?
Anyone have recommendations on AMC engine builder near KS?
Anyone have a ball park estimate on cost to rebuild AMC V8 from a decent builder, such as Jerry Tucker? I can add up the costs for all the parts, but machine work, head work I do not have a grasp on cost.
3 years ago I added FITech efi to it when I changed axles and suspension out. We went to Colorado after I got it done. After sustained RPM's up a mountain pass it developed an oil leak. I have fought that since that point up to a few months ago. Can drive around town and crawl for days and dry, but run it at highway speeds or sustained RPM for more than 40 min, oil everywhere. I resealed my intake, front cover, did some DUI distributor mods and got it to stop leaking after driving 50 miles at sustained rpm. Thought maybe I had won. We went back to Colorado this past month and on the way home I lost a trailer wheel bearing, and was forced to drive the jeep the remaining 430 miles, as I didn't think i could get the trailer fixed. Each gas stop, which was often, I looked for the oil leak to show up, which stayed dry all week on our trip. I made it about 380 miles before it started dripping. It is still much better than before, other than it took a quart of oil to travel home. It doesn't smoke that I can tell and has okay power as long as your not at altitude. I need to do a compression check, but I am to the point I believe the rings didn't seal or are stuck, the cylinders are glazed making crank pressure (PCV has been checked repeatedly), or I still have an intake issue. If either of cylinder thoughts are true then I have to tear it down. If it has to come out I don't want to put it back in.
I have an AMC401 on a stand that I could tear down and go through to see what it takes to rebuild, or I could find an LS.
I have been following this thread, but didn't want to hijack it as it had good info for what he was looking for. Posts 23,24,25 provided me some good info.
https://www.cj-8.com/threads/amc-360-build.48836/page-2#post-404027
I also read through this older thread and it had mixed opinions and seemed like the 401 was the choice to do.
https://www.cj-8.com/threads/opinions-on-engine.37289/
I know the 401 is going to cost $ to rebuild even if I don't have to do machine work and can get away with just pistons, bearings, cam, new timing cover, oil pump etc. Locally around KS am I not sure where I would take it to have work done. The Jerry Tucker post from the thread above was informative, but a long ways from KS. With the 401 I have to change nothing with my current setup, just put the motor together and it goes in the jeep. I already have EFI that works okay, hoping it will work better if the motor doesn't have possible internal issues. The LS I have to find, have harness work done, redo motor mounts, bellhousing to NP435, redo clutch setup, exhaust, probably have to do electric fans as well. Although the motor part of an LS swap using a 5.3 or 6.0 with a cam swap would be cheaper, the external items add up. I have not priced everything, but I can guess it would offset the cost vs the 401. The LS would maybe get better fuel mileage (better than 10 I get now?), would be more reliable, leak less oil in time, probably last longer, and probably make enough power to make me happy. As I understand from research the 401 should make more torque across the rpm band vs the LS until the upper RPM's which would be nice on a trail or just off idle. The 401 would also make enough power to make me happy and the exhaust note too.
I do a little of everything highway, around town, Colorado trails, semi local rock parks, and sand dunes. It would be nice to be able to drive the heep across country, but will probably continue to haul it. I am kind of stuck on what to do. The more I read and research the more I think going with the 401 is the best route. If I didn't have it the choice would be easier.
Anyone have thoughts on which route to go?
Anyone gone from a 360 or 401 to LS or vice versa? What did you like or not would you do it again?
Anyone have recommendations on AMC engine builder near KS?
Anyone have a ball park estimate on cost to rebuild AMC V8 from a decent builder, such as Jerry Tucker? I can add up the costs for all the parts, but machine work, head work I do not have a grasp on cost.