leaky 360

[fuzz401]

if that port is bigger then the one he is using for the pvc valve now he should use it then

[Old Rugged Crosser]

Dan,

As I looked at your pics one thing stands out to me. Masalba spotted the same thing. One thing you can do to help yourself is to modernize your ignition system. I would go to a simple HEI system a new one wire setup that has a self-contained 55K coil in the dist. cap. Along with some 8.5 wires to get all that voltage to your sparkers. You also need to open up the gap on them to allow the spark to better ignite the fuel mixture.

You need higher voltage to the plugs to force the spark to jump the wider gap under higher compression which you should have running propane. Your higher octane propane is not really doing you much good unless you have the higher compression to go along with it. 11-12:1 lbs. would be ideal. All the higher octane propane is doing for you is to knock back the pre-ignition or ping. You are not getting the power or torque out of it that you could be getting with your compression jacked up.

In the mean time do yourself a BIG favor and update that spark with a HEI. Bulltear has one listed.

[dan58]

So, I poked around with it (again) tonight. It DOES have a PCV valve...teeny little sucker that's mostly down in the grommet on the intake. As it sits, the vac of the small like is all but nothing. To the passenger side of the mixer is a yellow cap. It has HELLS of vacuum. Worth a shot?

Tell me about vac advance....

ORC, I just cannot justify putting any more money into this motor. I will buy the motor for sale by Fifesjeep on here, or I'm going with the aluminum L33 Chevy. I can get my hands on one for under a grand, and it'll push 375 hp with a tune and headers.

[Old Rugged Crosser]

Dan, One thing about replacing the dist. system you can use it on the next motor. Also I forgot to suggest that with that propane octane that you can bump up your advance to take advantage of it. Keep going up until it just starts to knock or ping on load then back up maybe 1 degree. If you don't advance it you are not taking advantage of the higher octane in creating torque and hp.

You will be doing yourself a big favor if you update your ignition system. That will be the biggest improvement you can make now for the bucks spent.

[dan58]

Hehe. My next motor won't have have the need. It'll likely have coil packs.

My motor will barely run without a big bump in timing. That's the first thing we did after rewiring it this winter. In all honestly, I have about as much done to this motor as I can without a bore and stroke. If I did rebuild it this winter, it would be in the 12:1 range to really push it.

[fuzz401]

PVC valve looks like

[Old Rugged Crosser]

Dan, I take it by your conversation that you are unhappy with the power that your AMC 360 is giving you and that you are considering a switch to the Bow tie. Having been in and around racing most of my life I can understand what it is like to see Bowtie owners running on by. It is a natural tendency to think that they have the magic Bullet. But you too can have a AMC bullet. The magic is not in the name or label. Match their cubic inches and you to can have like performance. Horsepower is not cheep in any motor. They too have to put their dollars down to get their performance.

One thing that I think is important to your type of racing is that simplicity is far easier to trouble shoot than is the complexity of highly engineered high tec systems. Given all things being equal horsepower has to be coaxed out, or tuned in. First off, you need to figure out all the parameters of your type of racing needs and design the motor around them. You will need to do this with whatever brand you use. It used to be that the bowtie was the easiest motor to work with because of the ease of quality parts available, now days that is not the case. It seems to me that there is no shortage of good parts for your AMC. Remember that horsepower has to be tuned into any motor and coaxed out in the details.

Your last post said that you have built your 360 as far as you can go without additional bore and stroke. But that pesky picture of your motor reveals that you have overlooked a big item in coaxing horsepower out of your present motor—the ignition system which is the brains of your process of coaxing out that hp. There is more than likely much more that you can do cam wise and also compression. How about roller rockers? Then there are all those little things that add up like all that goes into blueprinting. Add more bore and stroke and without paying attention to all the little details will only give you a bigger cubic in. to cover up the same failures, never realizing all the potential that they add. There is no easy way to good performance with out paying attention to the details no matter what the brand. Details and tuning is the key to making the most of what you have to work with. If you feel you lack motor knowledge find yourself a good motor man, especially one who knows how to tune. Big +.

Last winter you went to a lot of work to improve your suspension yet limit your potential performance. Get rid of that ancient ignition system if you are really serious about doing the best you can with what you have. I have a feeling that there are other areas that you can fine tune.

One other thing to keep in mind and that is that personal performance can many times do more with less. In my personal experience in racing (stock cars) I have many times run circles around those with bigger motors and greater horse power.

[dan58]

Thanks, Larry. What I'm seeing is the Gen II/IV Chevys putting down 375 horses with ease, while weighing in at a good 150 pounds less than my AMC mill. They're also a dime a dozen, which makes it pretty frustrating. I'd be happy with mine if it could churn out 350. The racing I do is best classified as 100 drag races in the course of 3-4 hours. The rock crawling part is always there, but the Jeep performs flawlessly there. I just don't have the umph to get those quick burts of acceleration needed for those 100 drag races on dirt.

I can't imagine anyone running 350hp with a 360 without (no NOS) opening it up with a bore, stroke, or higher compression. I'd LOVE to be proven wrong though!

You are also correct that I dumped my entire wad into suspension this winter. It's working wonderful at this point and is just in need of the fine tuning. I just need a motor to make the truck work to its fullest potential.

[Old Rugged Crosser]

Dan: Hope this helps

TWO AMC MOTOR BUILD EXAMPLES


AMC 360 Engine Build - 370-Inch 480HP AMC


Parts List Combo One
Part PN Source Price
AMC Block N/A Pick Your Part $89.00
Performer RPM Heads 60119 Edelbrock $1,519.90
Air-Gap Manifold 7531 Edelbrock $272.95
Distributor 8523 MSD $353.88
Connecting Rods 2-ICR-6000-2000 Scat $379.00
Rings 5525 Hastings $160.43
Small Cam 17-UH4-UH9 Lunati $185.00
Intake Gasket 800G Mr. Gasket $11.95
Head Gaskets 8266PT-1 Fel-Pro $22.69
Engine Gaskets KS2002 Fel-Pro $63.99
Spark Plugs R5671A-9 NGK $20.00
600 DP Carb 0-4776C Holley $299.88
Shorty Headers 65912 Edelbrock $363.39
Plug Wires 31199 MSD $74.88
Rocker Arms 133021 Ford
$167.31
Oil Pan 30260 Milodon $315.95
Oil Kit 24050 Milodon $270.39
Pistons Custom Lunati $750.00
Valve Covers AMC Indy Cylinder Head $255.00
Rings 2M5524 Hastings $160.43
Engine Bearings AMC 360 Clevite $116.29
Pushrods PR750S Elgin $19.04
Water Pump AMC 360 Chrysler
$45.17
Balancer AMC 360 Chrysler $72.40
Oil Galley Lines N/A Earl's $35.20
Timing Chain AMC 360 Chrysler $48.99
All Labor Performed by JMS Racing Engines, jmsracing.com
Blueprint Block $450.00
Weld Rods $98.00
Assemble Short-Block $250.00
Offset-Grind Crank $250.00
Balance $175.00
Total $1,223.00
Big Total




Building an AMC Brute
500 lb-ft and 484 hp From the Ugly American
By Douglas R. Glad
Photography by Bill Tichner

Want sick power from a basically stock engine? Try a 401. Using factoryheads on the portly 4.170-inch bore, you can build torque where itcounts and still make good power on top with a reasonable cam, goodvacuum, and off-the-shelf parts. In the case of the buildup we'reoutlining here, the payoff was 484 hp at a streetable 5,600 rpm andnearly 500 lb-ft of torque at 4,600, with more than 450 lb-ft from 2,500to the horsepower peak.
With the help of JT Payton at Payton's Performance, Holley MarketingManager Bill Tichner did all of that. His goal for the 401 was to use asmany stock parts as possible and create as much power as possible whilestill maintaining at least 13 inches of vacuum for an aftermarket fuelinjection system to come later. The performance key to this engine is heavy port work on the iron heads, attention to the oiling system, and a couple of other tricks we will outline in this story. This engine’s destiny is to be stabbed into an AMX, and with a little shot of spray, lift the wheels at its favorite track.
-
The Block
The practical limit of the plebian AMC 401 is about 500 hp at 7,500 rpm.The main caps will begin to walk above that, so limit these engines tohealthy street mills if you want to keep the price down and use stockparts. Just because we're interested in this kind of thing, we foundthat with an available four-bolt main kit, you can go to 700 hp and9,500 rpm for the full-race Chihuahua. Whee. But this is a streetengine, so Tichner used a post-'70, tall-deck block bored 0.030-over for4.195 inches and used the stock two-bolt main caps with big-block Chevystuds from ARP.
We'd recommend using the stock bore if you can. Payton's says the highnickel content in these blocks makes them resistant to wear, and0.030-over is on the limit of the 401's block design. So if you don'thave to bore, hone it and move on.

The Rotating Assembly
Lots of goodness here. The stock rods and crank on all AMC 390 and 401engines are forged from the factory. To keep them working, Payton's shot-peened the stock 5.85-inch rods to relieve stress and used a pressed piston pin for street durability and low bucks. For full-tilt mills, Payton's uses a 6-inch Chevy rod and turns the rod-bearing journal down to 2.100 inches from the stock 2.248 for reduced cylinder-wall loads and 7,500-plus-rpm capability. Taking no chances, they use ARP rod bolts as well.
The 401 crank has a 3.68-inch stroke and is more than manly enough with just a polishing of the journals and chamfering of the oil holes to live. It's worth mentioning that the '72-and-later 401 crank had a Torque Flite 727 flange, so look for the casting number 812-0510 or you will have to modify the flange to get it to work with a modern automatic.
We asked a couple of builders about off-the-shelf pistons and got head scratching and thinking but no part numbers. This engine uses a custom Lunati aluminum-alloy forged flat-top for future use of race gas and nitrous. At around $640, it is the most glaring expense on this engine. The slugs have a 1.48-inch compression height with two 17-degree valve eyebrows spaced 1.590 inches apart with a total of 11.23 cc's of relief. With a 0.043-inch thick gasket, 0.020-inch deck clearance, and the 64ccheads they're good for 10.0:1 compression.

Cylinder Heads
There are Indy and Edelbrock heads available for the AMC, but Tichner wanted to use the stock dog-leg heads. The cork in their design is the intake runner and the exhaust-port-to-header match. Payton's put in about 11 hours of work to cut the stock valve seats and fit a set of2.08 intake and 1.625 exhaust valves and raise the intake runner. Payton’s machinists are careful to avoid the intake floor, because past experiments found that changes there actually hurt airflow. Extensive work in the combustion chamber was performed to unshroud the valves and open the chamber from 58 to 64 cc's. This was also helpful in reducing the compression on this engine to run on pump gas. The final flow numbers were 279/210 cfm at 0.700-inch lift at 28 inches of water. Those are big ports for a cast-iron street head.
Dyno Chart
RPM HP TQ
3,500 309 464
3,600 322 471
3,700 331 470
3,800 338 467
3,900 346 466
4,000 356 467
4,100 366 469
4,200 378 473
4,300 394 481
4,400 409 489
4,500 423 493
4,600 436 498
4,700 445 497
4,800 450 492
4,900 454 486
5,000 457 480
5,100 461 475
5,200 467 472
5,300 472 468
5,400 478 465
5,500 482 460
5,600 484 454
5,700 483 445
5,800 474 430
5,900 469 417
6,000 469 411
On the exhaust side, the rough casting was cleaned up and the headerswere port matched to the heads. Early Super Comp 17/8-inch full-lengthheaders for the '68-'74 Javelin/AMX and '74 Matador need to have theflange opened up a bit to match the exhaust port, but new headers ofthis design should already be modified to fit.

Carb And Ignition
This engine was built with the future installation of Holley's Commander950 MPFI kit in mind. It has a single-plane manifold and throttle-body included. For the dyno run, Tichner used a manifold that is similar in design from Herman Lewis Racing and a 950-cfm Holley HP Series mechanical-secondary carb. The cfm might seem a little much, but this engine is going into a light AMX that will likely see more WOT on the track with a plate of nitrous than street cruising. According to Payton’s dyno sheet, the A/F ratios were correct for this size carb on this combination.
MSD offers both a standalone ready-to-run distributor and the Pro-Billet that requires an MSD 6-, 7-, 8- or 10-series ignition to operate. Both come with a vacuum advance and replace the stock points stuff. Tichner chose the Pro-Billet and a set of Autolite AR52 racing plugs to spark itall.

Cam and Valvetrain
The cam was a sacrifice to get some vacuum at a loaded idle. It is a Lunati hydraulic flat-tappet grind with 230/235 degrees of duration at0.050, a valve lift of 0.0523/0.0540, and 108 degrees of lobe separation. The full-kill cam is also a Lunati grind, but it uses a solid lifter and has 249/259 degrees at 0.050 and 0.579/0.598 lift with the same lobe separation angle. It will sacrifice more idle quality and vacuum but would likely crest 500 hp on this combination. The rocker arms are aluminum rollers made for a Ford 260-351W but useable on the090 and 993 castings with Lunati springs with 105 pounds of seat pressure at 1.80-inch installed height.

The AMX
Ultimately, the engine is destined for Tichner's AMX. We'll let him tell its story.
I have a Torque Flite 727 that I got with the 401 out of the donor'73 International Travel-all, but I am not sure if I will build it or something else at this point. I still need to build the rear-end to handle the power as well. I know I want 3:55 gears and probably a 2,500stall since the torque comes on immediately from this motor. The car was originally a 390-cid car. I bought it with a 290 and then put ahigh-compression 360 in it during college. Now it has the 401. I am going with the multipoint EFI so the factory hood will be able to close. You can't get this kind of power out of an AMC and keep it under thestock hood with a carb."

Tips and Tricks
It's no secret that the AMC V-8 has a failing in its lubrication system. Oil from the pickup travels through a passage on the oil-pan rail into a pump with an aluminum housing that tends to wear, then to the filter, and finally to the main oil galley. It's nowhere near good enough for even a stocker, in our opinion. The solution is the Milodon single or dual pickup that bolts directly (and conveniently) to a Milodon deep-sump oil pan. It bypasses the stock restriction and nearly double soil flow to the filter and mains. Payton's adds a filter before the oil reaches the pump gear in conjunction with a direct-oil feed from the main galley in the lifter valley to the rear main bearings, because on a stock AMC, they're the last in line and tend to fail during high-rpm use.
Stock AMC oil-filter adapters are made of aluminum, and the pump-gear face rides directly on the housing and wears it down. Fortunately Speed Pro sells a replacement kit for the oil-pump gear assembly and pressure spring, and we've seen the 340/360 Mopar service replacement housing being used for 390/401 performance applications, so look to Jeeps fort his part.
Payton's Performance AMC Engine Build Specs

Part Mfr. PN
Block AMC Stock
Main studs ARP 135-5002
Main bearings Speed Pro 4950 M
Crank AMC Stock crank
Rods AMC Stock (5.85
Rod bearings Speed Pro 8-3385CP
Rod bolts ARP 114-6002
Pistons Lunati custom
Rings Speed Pro R-9349 35
Pin AMC Stock
Pan Milodon 30260
Oil line Milodon 24050
Oil pump Speed Pro 224-51285
Timing cover AMC Original
Cam Lunati 31799
Cam bearings Speed Pro 1401 M
Lifters Lunati 71963
Springs Lunati 73126
Rockers Lunati 84161
Valves int. Milodon 45027-8
Valves exh. Milodon 45047-8
Heads AMC 1973
Head gasket Fel Pro 8266PT1
Headers Hooker 7103-1
Intake Herman Lewis Racing call
Intake bolts ARP 414-2001
Carburetor Holley 0-80496-1
Distributor MSD 8519
Spark plugs Autolite AR52 Racing
Fuel pump Holley 12-802
Valve covers Payton's Performance call
Damper ATI 917943
Crank pulley Moroso 64100
Water pump Milodon 16270
Timing chain Milodon 15000
Oil line to rear main:
3/8 NPT to 8-AN, straight Earl's Performance 820108ERL
3/8 NPT to 8-AN, 45 deg. Earl's Performance 824508ERL
Perform-o-Flex hose Earl's Performance 403008ERL
Payton's Performance
www.paytonsperformance.com

[fifesjeep]

Dan,
just buy my 360 for $2000... you'll end up saving money.