There's a great AMC 360 performance article from Car Craft Magazine.
AMC 360 Engine Build - 370-Inch 480HP AMC
Got an AMC? Why build a hard-to-find 390 or 401 when the 360 grows on Jeeps? Follow along as we build a 370-Inch 480HP AMC
By Douglas R. Glad
Photography by Douglas R. Glad
[FONT="][/FONT]http://www.carcraft.com/techarticles/ccrp_0601_amc_360_engine_build/photo_01.html
It was nearly a year ago that we got the jones to build an AMC. After checking prices on the most popular AMX and '70 Javelin bodies, we found them priced out of our budget just like every other desirable musclecar from that era. Our solution was simple: the Rambler American. We found 290 V-8 cars for around $1,000 in hammered shape and some in minty-fresh factory condition with six-cylinder/auto running gear for about twice that. We scored a '67 with a
AMC 232 i6 and a two-speed for $2,000. Our big plan was to swap in a 390 or 401 for a little street-machine fun. That was before we found out that a broken-core block was $200 and running engines were clearing a grand.
We found a fast solution for that too when the Jeep guys divulged the secret of the AMC 360. No, it's not a Mopar engine, it's all American Motors with a 4.08 bore and 3.44-inch stroke destined for the big-body Javelin, 360 Hornet, and a healthy mix of Wagoneers and other vehicles with a production run from 1970 to 1991 (or 1992 depending on who you ask). We took a trip to Pick Your Part in Sun Valley, California, to have a look for one. We found five 360s in various states of disassembly, so we got to pick and choose. We selected an '85 Jeep Grand Cherokee because someone had already pulled the hood, radiator, and most of the useless junk out of the way. We swooped on it and pulled it in about an hour. Total price for the short-block? $89.
CC/Rambler
The 360 uses cast internals and has a couple of hereditary oiling problems that need to be dealt with before you can make good power. There are forged rods with pistons available for the 360, but they usually represent part of a rotating-assembly combo that gives you around 9.0:1 compression with 53 cc. We wanted at least 10.5:1 so we could have decent snort and use gas from the pump. For this we opted to use Chevy 6-inch small-journal rods and custom pistons from Lunati. The price for the combo is roughly the same as other aftermarket AMC assemblies, because the low price of the rods offset the expensive pistons whereas other AMC rotators are 50/50. Just plan to spend $1,000 and pick your compression ratio.
Finally we used all the common bolt-on parts from Edelbrock that are available ready to install off the shelf.
The stock pickup feeds the...
read full caption
The stock pickup feeds the oil galley through this hole. There are dual-feed systems available that use the stock hole and an external line, but we plugged it and used the Milodon single-line pickup.
We took the parts to JMS Racing Engines in Monrovia, California, to assemble and dyno-test four different combos that represent what the average street-machine guy would build using new bolt-on parts from Edelbrock then pushed it to the level of the weekend racer with a larger cam, intake, and big tube headers to see what it could do. Check it out.
Short-Block Assembly
The biggest hurdle in assembling the short-block is the oiling system. The stock path for AMC engines is from a pickup in the sump, through the block via an oil galley then into the oil pump, then eventually to the mains, starving the No. 4 and 5 main bearings at high rpm. We used a Milodon deep sump that is designed to accept an external pickup and feeds the oil pump directly with a braided-steel line that bolts between the stock oil-pump body and oil-filter-adapter body. This, in combination with an AN -6 line from the main oil galley to the rear of the lifter valley, gave us 80 psi of oil pressure at 6,000 rpm.
Otherwise we used the stock crank offset ground to accept the 2.00 big end of a Scat 6-inch Chevy-style rod. Since the stock rod is wider than the Scat I-beams, to use them, AMC guys must weld the crank filet or the big end of the rod to get them to fit. That and the custom Lunati piston gave us a zero deck after cleaning up the head 0.010 to 9.198.
The pan and the pickup clear...
The pan and the pickup clear both the long-tube Hooker and the short-tube Edelbrock headers. We'll let you know how it fits pan-to-crossmember when we install it in the car.[FONT="][/FONT]
The Milodon pan is pretty...
The Milodon pan is pretty straightforward. Looks like it would also work as a road-race pan with a deep sump and a swivel pickup.[FONT="][/FONT]
To offset-grind the crank...
To offset-grind the crank is to take material off one side of the rod journal to fit the big end of a smaller-than-stock rod. That moves the centerline of the rod journal further from the mains-that's where we get the extra stroke. Mike Johnson at JMS did a bit of counterbalance work as shown here. The Chevy-style rod and forged piston weighed about 590 grams;
AMC 150 lighter than stock.[FONT="][/FONT]
AMC 360 Engine Build - 370-Inch 480HP AMC
We used Chevy-style small-journal...
We used Chevy-style small-journal 6-inch rods for their low price, stronger material, and their length, which means less side loading of the piston and more dwell. They are narrower than stock, so JMS recommends welding material onto the rods for no less than 0.007 and no more than 0.020 clearance between them.[FONT="][/FONT]
If you scan down a list of...
If you scan down a list of AMC engines, you'll notice there are changes in bore and stroke and a major increase in deck height in 1970 to 9.208 inches. You'll need the tall deck block for this combo. The beefy mains use 1/2-inch bolts that torque to 100 lb-ft (Chevy and Ford small-blocks use 7/16 bolts torqued to 70 lb-ft).[FONT="][/FONT]
The piston was custom made...
The piston was custom made by Lunati. Its bore is 4.1065 with a 1.453 compression height. They are forged (nitrous, heh heh) and use Ford style 1/16 rings. With 53cc heads, we had 10.5:1 compression.[FONT="][/FONT]
The big Lunati cam only delivered...
The big Lunati cam only delivered 8 inches of vacuum at 900 rpm, so it's good we have no power brakes. It has 254/259 at 0.050 with 0.555/0.567 lift using a 1.6:1 rocker ratio. That is right at the edge of what Edelbrock recommends for maximum lift, but we wanted to see what they could do.[FONT="][/FONT]
The Edelbrock heads can be...
The Edelbrock heads can be used on both early (7/16) and late-model (1/2) cylinder blocks and comes with parts for the late block.[FONT="][/FONT]
Combo One: Small Carb, Small Headers, And Edelbrock Heads
The first run consisted of a pair of out-of-the-box Edelbrock Performer RPM cylinder heads. They are an aluminum design using an exhaust port similar to dog-leg heads you've heard about with 2.02/1.60 valves and an 185cc intake volume. At the Westech flowbench with a 4.
AMC 150 bore, they flowed 252/162 at 0.500 lift. With a 53cc chamber, they are slightly larger than the stock 51cc production heads.
For a little throttle response and street usability, we used a Holley 600-cfm DP carb with a manual choke, 1 5/8 shorty headers to allow for ground clearance, and the new Edelbrock AMC RPM Air-Gap manifold. The Air-Gap takes all the low-end torque characteristics of a dual-plane intake and combines them with high-rpm flow usually providing more torque as well. On this engine, the intake should beat the old Torker style in peak horsepower and make the same peak power without the sacrifice, a claim tested in Combo 3.
Power
Peak HP: 455.5 @ 6,000
Peak Torque: 440.8 @ 4,100
Although stock rocker arms...
Although stock rocker arms can be used with new locknuts, why bother? We used a set designed for a 302 Ford with poly locks, but you can also use long-slot roller-tip rockers such as Comp Cams PN 1416-16.[FONT="][/FONT]
AMC 360 Engine Build - 370-Inch 480HP AMC
Combo Two: Hooker Long Tubes, Holley HP 750 Carb
We went directly for the long tubes on this one to see how much we were giving away with the shorties. As predicted, the long tubes made more torque higher in the powerband and added horsepower at 6,000 rpm. We also noticed the vacuum reading at WOT was 1.8 inches, an indication that the 600-cfm carb was becoming a restriction. We installed an HP 750 carb and picked up 5 lb-ft of torque and a couple of horsepower at the top while improving the WOT reading to 1.4 inches.
Power
Headers
Peak HP: 467.4 @ 6,000
Peak Torque: 451.4 @ 4,600
Carb Swap
Peak HP: 468.9 @ 5,900
Peak Torque: 454.7 @ 4,500
We've seen the long-tube 1...
We've seen the long-tube 1 5/8 Hooker Headers on a few AMCs but never on a Rambler. They make power, but we might use the Edelbrock shorties in the car. A recent redesign enlarges the opening near the bottom of the exhaust port that eliminates power loss and cooked gaskets.[FONT="][/FONT]
The 750 HP carb has been updated...
The 750 HP carb has been updated with smoothed venturi transitions lacking choke horns and screw-in air bleeds for tuning. There was a gain in throttle response that you could hear and a couple of bonus horsepower. The real gains are going to be on the track with tuning and 60-foot times.[FONT="][/FONT]
Combo Three: Intake Swap Torker
We see these intakes at every AMC event and every adjoining swap meet. The Torker is a single-plane design from back when the single-plane meant everything. We bolted it on expecting the RPM Air Gap to kick it around. Down in the lower-rpm range, it did. The Air Gap beat it by about 12 lb-ft on average and nearly 800 rpm lower in the band. But after 5,300 rpm, the Torker managed to pull away by 12 hp all the way to 6,000, proving for pure WOT, it's still hard to beat a single-plane. Looks cool too.
Power
Peak HP: 480.7 @ 6,000
Peak Torque: 448.3 @ 4,900
We used the MSD Ready-to-Run...
We used the MSD Ready-to-Run distributor set at 35 degrees total. It doesn't need a separate box to run, just a couple of wires to power and ground.[FONT="][/FONT]
Indy Cylinder Head makes arguably...
Indy Cylinder Head makes arguably the best valve covers for the AMC. They have no provisions for an oil-fill tube or a PCV, but if you are using an Edelbrock manifold, it takes care of those for you.[FONT="][/FONT]
AMC 360 Engine Build - 370-Inch 480HP AMC
Combo Four: Lunati "Small" Cam
For you guys who want to run power brakes and have a milder idle, we swapped in a smaller Lunati cam with 221/230 @ 0.050 and 0.484-inch intake/exhaust lift with a 1.6:1 rocker. It pulled 12-14 inches of vacuum at 800 rpm and made over 450 lb-ft of torque starting at 3,500 rpm with a fat peak of 470 lb-ft at 3,900. Wanna burn rubber sideways on the way to work? Here you go.
Power
Peak HP: 437.2 @ 6,000
Peak Torque: 470.8 @ 3,900
The "little" cam and the dual...
The "little" cam and the dual plane conspired to make the most average torque and horsepower at the lowest rpm with the best vacuum at idle and least popping and complaining on the dyno. Street combo? You decide.[FONT="][/FONT]
370 Specs
Displacement: 370.36
Deck Height: 9.198
Bore: 4.11
Stroke: 3.490
Rod Journal: 2.00
Final Compression: 10.5:1
Rod Length: 6.00-inch small-journal Chevy
Piston Compression Height: 1.453
Combustion Chamber: 54 cc
Valves: 2.02/1.60
Valve Spacing: Stock 1.940
Valve Angle: Stock 18 degrees
Final Compression: 10.5:1
Cam Specs
Small Cam
PN 31799
Grind No. 17-UH4-UH9
EXH Closes 3 ATDC
EXH Opens 47 BBDC
INT Opens 6.5 BTDC
INT Closes 34.5 ABDC
Lope Sep 108
104 Centerline
Lift 0.484
221/230 @ 0.050
276/286 advertised
Big Cam
PN 31799
Grind No. 17-UH22-UH23
EXH Closes 17.5 ATDC
EXH Opens 61.5 BBDC
INT Opens 23 BTDC
INT Closes 51 ABDC
Lope Sep 108
104 Centerline
Lift 0.555
254/259 @ 0.050
310/318 advertised
AMC 360 Engine Build - 370-Inch 480HP AMC
Parts List Combo One[FONT="][/FONT]
[FONT="][/FONT]
PN[FONT="][/FONT]
Source[FONT="][/FONT]
Price[FONT="][/FONT]
AMC Block[FONT="][/FONT]
N/A[FONT="][/FONT]
Pick Your Part[FONT="][/FONT]
$89.00[FONT="][/FONT]
Performer RPM Heads[FONT="][/FONT]
60119[FONT="][/FONT]
Edelbrock[FONT="][/FONT]
$1,519.90[FONT="][/FONT]
Air-Gap Manifold[FONT="][/FONT]
7531[FONT="][/FONT]
Edelbrock[FONT="][/FONT]
$272.95[FONT="][/FONT]
Distributor[FONT="][/FONT]
8523[FONT="][/FONT]
MSD[FONT="][/FONT]
$353.88[FONT="][/FONT]
Connecting Rods[FONT="][/FONT]
2-ICR-6000-2000[FONT="][/FONT]
Scat[FONT="][/FONT]
$379.00[FONT="][/FONT]
Rings[FONT="][/FONT]
5525[FONT="][/FONT]
Hastings[FONT="][/FONT]
$160.43[FONT="][/FONT]
Small Cam [FONT="][/FONT]
17-UH4-UH9 [FONT="][/FONT]
Lunati[FONT="][/FONT]
$185.00[FONT="][/FONT]
Intake Gasket [FONT="][/FONT]
800G [FONT="][/FONT]
Mr. Gasket[FONT="][/FONT]
$11.95[FONT="][/FONT]
Head Gaskets[FONT="][/FONT]
8266PT-1[FONT="][/FONT]
Fel-Pro[FONT="][/FONT]
$22.69[FONT="][/FONT]
Engine Gaskets[FONT="][/FONT]
KS2002[FONT="][/FONT]
Fel-Pro[FONT="][/FONT]
$63.99[FONT="][/FONT]
Spark Plugs[FONT="][/FONT]
R5671A-9[FONT="][/FONT]
NGK[FONT="][/FONT]
$20.00[FONT="][/FONT]
600 DP Carb[FONT="][/FONT]
0-4776C[FONT="][/FONT]
Holley[FONT="][/FONT]
$299.88[FONT="][/FONT]
Shorty Headers[FONT="][/FONT]
65912 [FONT="][/FONT]
Edelbrock[FONT="][/FONT]
$363.39[FONT="][/FONT]
Plug Wires[FONT="][/FONT]
31199[FONT="][/FONT]
MSD[FONT="][/FONT]
$74.88[FONT="][/FONT]
Rocker Arms[FONT="][/FONT]
133021[FONT="][/FONT]
Ford[FONT="][/FONT]
$167.31[FONT="][/FONT]
Oil Pan[FONT="][/FONT]
30260[FONT="][/FONT]
Milodon[FONT="][/FONT]
$315.95[FONT="][/FONT]
Oil Kit[FONT="][/FONT]
24050[FONT="][/FONT]
Milodon[FONT="][/FONT]
$270.39[FONT="][/FONT]
Pistons[FONT="][/FONT]
Custom[FONT="][/FONT]
Lunati[FONT="][/FONT]
$750.00[FONT="][/FONT]
Valve Covers[FONT="][/FONT]
AMC[FONT="][/FONT]
Indy Cylinder Head[FONT="][/FONT]
$255.00[FONT="][/FONT]
Rings[FONT="][/FONT]
2M5524[FONT="][/FONT]
Hastings[FONT="][/FONT]
$160.43[FONT="][/FONT]
Engine Bearings[FONT="][/FONT]
AMC 360[FONT="][/FONT]
Clevite[FONT="][/FONT]
$116.29[FONT="][/FONT]
Pushrods[FONT="][/FONT]
PR750S[FONT="][/FONT]
Elgin[FONT="][/FONT]
$19.04[FONT="][/FONT]
Water Pump[FONT="][/FONT]
AMC 360[FONT="][/FONT]
Chrysler[FONT="][/FONT]
$45.17[FONT="][/FONT]
Balancer[FONT="][/FONT]
AMC 360[FONT="][/FONT]
Chrysler[FONT="][/FONT]
$72.40[FONT="][/FONT]
Oil Galley Lines[FONT="][/FONT]
N/A[FONT="][/FONT]
Earl's[FONT="][/FONT]
$35.20[FONT="][/FONT]
Timing Chain[FONT="][/FONT]
AMC 360[FONT="][/FONT]
Chrysler[FONT="][/FONT]
$48.99[FONT="][/FONT]
All Labor Performed by JMS Racing Engines, jmsracing.com[FONT="][/FONT]
Blueprint Block[FONT="][/FONT]
$450.00[FONT="][/FONT]
Weld Rods[FONT="][/FONT]
$98.00[FONT="][/FONT]
Assemble Short-Block[FONT="][/FONT]
$250.00[FONT="][/FONT]
Offset-Grind Crank[FONT="][/FONT]
$250.00[FONT="][/FONT]
Balance[FONT="][/FONT]
$175.00[FONT="][/FONT]
Total[FONT="][/FONT]
$1,223.00[FONT="][/FONT]
Big Total[FONT="][/FONT]
$7,296.11[FONT="][/FONT]
[FONT="][/FONT]
Optional Stuff[FONT="][/FONT]
Torker Manifold[FONT="][/FONT]
2930[FONT="][/FONT]
Edelbrock[FONT="][/FONT]
$255.95[FONT="][/FONT]
Big Cam[FONT="][/FONT]
17-UH22-UH23[FONT="][/FONT]
Lunati[FONT="][/FONT]
$185.00[FONT="][/FONT]
750 Carb Street HP[FONT="][/FONT]
0-82751[FONT="][/FONT]
Holley[FONT="][/FONT]
$499.95[FONT="][/FONT]
Long Tube Headers[FONT="][/FONT]
7901-1HKR[FONT="][/FONT]
Hooker[FONT="][/FONT]
$374.95[FONT="][/FONT]
SOURCES[FONT="][/FONT]
Autotronic Controls Corp. (MSD)[FONT="][/FONT]
Lunati (A Division of Holley)[FONT="][/FONT]
El Paso, TX[FONT="][/FONT]
Memphis, TN[FONT="][/FONT]
915/ 857-5200[FONT="][/FONT]
901/365-0950[FONT="][/FONT]
msdignition.com[FONT="][/FONT]
lunaticamshafts.com[FONT="][/FONT]
[FONT="][/FONT]
[FONT="][/FONT]
Comp Cams[FONT="][/FONT]
Milodon[FONT="][/FONT]
Memphis, TN[FONT="][/FONT]
Simi Valley, CA[FONT="][/FONT]
800/999-0853[FONT="][/FONT]
805/577-5950[FONT="][/FONT]
compcams.com[FONT="][/FONT]
milodon.com[FONT="][/FONT]
[FONT="][/FONT]
[FONT="][/FONT]
Galvin's Rambler Parts[FONT="][/FONT]
Power Master Motorsports[FONT="][/FONT]
Lodi, CA[FONT="][/FONT]
Knoxville, TN[FONT="][/FONT]
209/365-6315[FONT="][/FONT]
865/688-5953[FONT="][/FONT]
ramblerparts.com[FONT="][/FONT]
powermastermotorsports.com[FONT="][/FONT]
[FONT="][/FONT]
[FONT="][/FONT]
Holley Performance Products[FONT="][/FONT]
Scat Enterprises[FONT="][/FONT]
Bowling Green, KY[FONT="][/FONT]
Redondo Beach, CA[FONT="][/FONT]
800/HOLLEY-1[FONT="][/FONT]
310/370-5501[FONT="][/FONT]
holley.com[FONT="][/FONT]
scatcrankshafts.com[FONT="][/FONT]
[FONT="][/FONT]
[FONT="][/FONT]
Indy Cylinder Head[FONT="][/FONT]
Payton's Performance[FONT="][/FONT]
Indianapolis, IN[FONT="][/FONT]
Horse Branch, KY[FONT="][/FONT]
317/862-3724[FONT="][/FONT]
(270) 274-9877[FONT="][/FONT]
indyheads.com[FONT="][/FONT]
paytonsperformance.com[FONT="][/FONT]
[FONT="][/FONT]
[FONT="][/FONT]
JMS Racing Engines[FONT="][/FONT]
[FONT="][/FONT]
Monrovia, CA[FONT="][/FONT]
[FONT="][/FONT]
626/357-2718[FONT="][/FONT]
[FONT="][/FONT]
jmsracing.com[FONT="][/FONT]
[FONT="][/FONT]
