Well I picked up a new motor today...

Well I picked up a new motor today...
R

rumblephish

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Central California
Vehicle(s)
1978 Jeep CJ-5 "Levi's" edition, original AMC 304 V8, T-150 transmission, Dana 20 transfer case, AMC 20 rear end. All stock except for a hotter ignition.
well, new to me anyway.


My best bud was kind enough to drive up to Antelope, CA. with me and help me pick up an AMC 360 out of a 1979 Jeep Grand Wagoneer. Got a nice long block for $350 plus a gently used heater assembly box for my CJ5 .

Not a bad deal considering the timing cover kit for the engine runs $300+. Now I just have to order a water pump and some gaskets to get the AMC 304 up and running while I tear down the 360 and give it a little massage. I'm going to have it over-bored .030, have the crank undercut .010, put in new pistons (hopefully bring up the compression to 9:1), a hotter cam (Summit 8600), double roller timing chain and gears (Summit), roller rockers (Scorpion), new valves and a good 3 angle valve job, shorty headers (Edelbrock), 4 bbl intake (Edelbrock)), and a 750cfm 4bbl carb from Summit Racing. I'll swap over the smog stuff and the OEM intake /carb when I need to get it smogged. I've seen similar 360 set up this way producing in the range of 325-350hp and 365-390lbs of torque. I'll be beefing up the clutch and looking for either a 4spd Transmission like the T-18 (4:1 first) or a new 4:1 rebuild kit for the Transfer Case . That way I won't have to mess with the diff. gears (3:73's)

I'll post up pic's once I start to tear it down. Right now it's just a greasy lump

Can't wait to get started
 
Great find rumblephish! Sounds like you have a plan.

I'm just a little confused about the crank grinding though? Why grind it if it doesn't need it? Did the engine spin a bearing? If it didn't, just polish those journals, don't spend the money on a regrind... :)
 
I agree, never take off material that is not needed
 
Cheepjeep85 said:
i don't think he's tore it down yet, he may just be planning ahead. assuming the bearings chewed up the crank. if you do have to turn the crank i wouldn't use it if they have to turn more than 10
Click to expand...

I've seem lots of motors live long happy lives with cranks that had been ground .020 under.

But mike it to see if it needs anything but polishing, unless of course a bearing spun.
 
he's hoping to make a bit of a hotrod out of it, 365-390 ft lbs of torque, which means he'll have his foot in it alot, with a motor like that i'd keep it under .10 . if it was a stock build daily driver, or a dirt track claim engine then yeah .20 under is fine. its an opinion everybody has one, and well you know.
 
Cheepjeep85 said:
he's hoping to make a bit of a hotrod out of it, 365-390 ft lbs of torque, which means he'll have his foot in it alot,.
Click to expand...

What that means is he'll be asking what to replace that AMC20 with.:D
 
Hey guys, thanks for the props and the advice. Yes, I am planning ahead on the crank but I pulled the intake and the valve covers last night and so far everything looks pretty good. If the crank looks good than just a polish will suffice. I'm hoping that everything on the bottom end will be A-O.K. I don't know the history of this motor other than it came out of a 1979 Grand Wagoneer. Do you guys think my estimates for hp/tq are realistic considering the build I'm planning? I had initial plans of dressing the motor up and making it look all shiny and pretty under the hood but seeing as I live in Kalifornia I've decided to disguise it as a mild mannered AMC 304 , complete with all the factory goodies to keep a stock look. What they don't know won't hurt them :)

As for the AMC20 rear end I'm planning on one piece axles and an air locker down the road. Will the one piece swap handle the kind of power I'm looking for? I want to keep it all AMC if possible. I also have one question about the motor. This is the first time I've had an AMC apart and stamped in the lifter galley are the numbers "360" which I can safely assume are there because this motor is a 360. But there are also the numbers, stamped smaller, just after the 360 that read "343". Is that common? I didn't get a 343 passed off as a 360 did I?
 
Last edited:
rumblephish said:
well, new to me anyway.


My best bud was kind enough to drive up to Antelope, CA. with me and help me pick up an AMC 360 out of a 1979 Jeep Grand Wagoneer. Got a nice long block for $350 plus a gently used heater assembly box for my CJ5 .

Not a bad deal considering the timing cover kit for the engine runs $300+. Now I just have to order a water pump and some gaskets to get the AMC 304 up and running while I tear down the 360 and give it a little massage. I'm going to have it over-bored .030, have the crank undercut .010, put in new pistons (hopefully bring up the compression to 9:1), a hotter cam (Summit 8600), double roller timing chain and gears (Summit), roller rockers (Scorpion), new valves and a good 3 angle valve job, shorty headers (Edelbrock), 4 bbl intake (Edelbrock)), and a 750cfm 4bbl carb from Summit Racing. I'll swap over the smog stuff and the OEM intake /carb when I need to get it smogged. I've seen similar 360 set up this way producing in the range of 325-350hp and 365-390lbs of torque. I'll be beefing up the clutch and looking for either a 4spd Transmission like the T-18 (4:1 first) or a new 4:1 rebuild kit for the Transfer Case . That way I won't have to mess with the diff. gears (3:73's)

I'll post up pic's once I start to tear it down. Right now it's just a greasy lump

Can't wait to get started
Click to expand...

Sounds good, but IMHO your to big on the carb & would get better response with a smaller unit. a 360ci @6000 RPM 100%V.E. only calls 625CFM;)
 
LongHorn said:
Sounds good, but IMHO your to big on the carb & would get better response with a smaller unit. a 360ci @6000 RPM 100%V.E. only calls 625CFM;)
Click to expand...

Thanks for the heads up on the carb. I know this has probably been asked to death, but what carb should I be looking at? Mostly street driving with a trip up to the Sierra's a couple or three times a year. Nothing too crazy, just fire roads and deer trails mostly.

Holley Truck Avenger? I've heard a lot of bad things about the Edelbrocks off road. How about their Thunder Off-Road series? I was considering the Summit carbs mostly because of price point but does anyone have any experience with them?
 
LongHorn said:
This is out of Hot Rod Magazine.
View attachment 2813

View attachment 2814

View attachment 2815

View attachment 2816

View attachment 2817
Click to expand...


Great article, but now my eyes hurt from trying to read the blurry text! :D


The most interesting part was the oiling mod they did right through the timing cover. I found a .pdf online that details this mod. Are you guys familiar with this mod? I've already printed out and studied the internal oiling mod and the mods to the oil passages in the oil pump housing on this forum but I haven't seen the timing cover mod. Would the oil passage mods serve the same purpose? Is the timing cover mod one i should consider?
 
rumblephish said:
Thanks for the heads up on the carb. I know this has probably been asked to death, but what carb should I be looking at? Mostly street driving with a trip up to the Sierra's a couple or three times a year. Nothing too crazy, just fire roads and deer trails mostly.

Holley Truck Avenger? I've heard a lot of bad things about the Edelbrocks off road. How about their Thunder Off-Road series? I was considering the Summit carbs mostly because of price point but does anyone have any experience with them?
Click to expand...

I like Holley's.
I grew up with them, so I guess it was I know.
The Truck Avenger is pricey.
That's what I run & have nothing, but good thing to say about it.;)
 
rumblephish said:
Great article, but now my eyes hurt from trying to read the blurry text! :D


The most interesting part was the oiling mod they did right through the timing cover. I found a .pdf online that details this mod. Are you guys familiar with this mod? I've already printed out and studied the internal oiling mod and the mods to the oil passages in the oil pump housing on this forum but I haven't seen the timing cover mod. Would the oil passage mods serve the same purpose? Is the timing cover mod one i should consider?
Click to expand...

I didn't do the timing cover mod on mine either.
That was just for the distributor gear & timing chain.
I did drill the drain back holes in the lifter valley & the oil pump mod.
Also the valley equalization tube & the rear main & rod line.
 
rumblephish said:
Great article, but now my eyes hurt from trying to read the blurry text! :D


The most interesting part was the oiling mod they did right through the timing cover. I found a .pdf online that details this mod. Are you guys familiar with this mod? I've already printed out and studied the internal oiling mod and the mods to the oil passages in the oil pump housing on this forum but I haven't seen the timing cover mod. Would the oil passage mods serve the same purpose? Is the timing cover mod one i should consider?
Click to expand...

If you save the pic's to your hard drive you can zoom in, it make it easier for me anyway.;)
 
Cheepjeep85 said:
i think you can make the AMC20 hold up to the power if you don't go crazy on big tires, add a truss, and weld the axle tubes, along with a good one piece kit i think you'll be ok
Click to expand...



I'm running 32's right now and I'll be stepping up to 33's when all is said and done. I'm looking at Supieior axles. I didn't think about the truss, thanks. I'm reading up on how to beef up the 20.... :D
 
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