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Mopar 360 Engine - Battle Of The Titans

Mopar 360 Buildup

Photography by Marko Radielovic

Editor's NoteThe concept of our new Battle of the Titans series is simple: To show entry-level car crafters how to make good power with basic parts and a limited budget without sacrificing quality or reliability. Over the next three months, culminating in our Nov. '03 issue with a three-way Chevy, Ford, and Mopar dyno shootout, our staff will build three everyman's motors that will stand on their own as well as be good foundations for later enhancements. Our subjects are a Mopar 360, a Ford 351 Windsor, and a Chevy 350, and to keep it simple, we're limiting all three to a few basic rules: stock blocks and rotating assemblies, factory cast-iron cylinder heads, Crane hydraulic flat-tappet camshafts, dual-plane intake manifolds, pump-gas streetability, and most important-a $2,500 budget for everything except the carb, ignition, and headers, including basic machine work. In the first three installments, we'll detail the buildups of each engine in the series, highlighting the parts selections, pricing, and machine work and assembly required for each, but we're keeping the dyno results a secret (even from each other) until we round up all three in November for a three-way showdown that will pit staffer against staffer in a battle for brand-name bragging rights. Battle of the Titans kicks off this month with Mopar Man Marko Radielovic's 360 buildup; next month we follow-up with Ford Fanatic Henry De Los Santos's 351 Windsor, and in October, GM Guru Terry McGean rolls out his 350 Chevy. -Matt King

The Mopar 360 buildup came first in the Battle of the Titans series by default. It was the only core we already had in our possession (sometimes it pays to be a pack rat) so it had a head start. Mopar's LA-series small-block 360 is a solid performance design featuring a healthy 4-inch bore, a relatively long 3.58-inch stroke, long 6.123-inch rods, and a desirable 18-degree cylinder head valve angle-the last three being things you pay a lot extra to get in a Chevy. Its stock 0.904-inch lifter diameter also helps cam grinders incorporate prodigious amounts of lift relative to duration into the cam profile, while the shaft-mounted rocker-arm system offers extra valvetrain stability. That said, we only had $2,500 with which to carefully select moderate, but quality, parts, and low-priced parts are fewer and farther between for a Mopar than with a bellybutton Chevy. Fortunately our budget didn't need to include such peripherals as carburetor, headers and ignition-those items will be standardized across all three engines in the series. We were able to specify quality Hooker headers and a Road Demon Jr. carburetor to round out our budget buildup, while an MSD distributor was borrowed from another project.

The biggest obstacle to making big power in this case was cylinder-head selection. Under the rules, our options were limited to factory production cast-iron offerings. Our choices were to either build a cheap short-block with good heads, or a good short-block with marginal heads. We chose the latter because we wanted a good foundation to build upon at a later date. Mopar Performance's Magnum RT performance heads seemed a logical choice for our 360, but proved to be more pricey than we were willing or able to spend on the top-end without sacrificing the bottom-end's quality. Reconditioned 360 castings were ultimately chosen to regulate the engine's breathing, but more on that later (see Cylinder Heads sidebar).

Our rules and budget dictated using the stock crankshaft, stock connecting rods resized and bolstered with new Pioneer rod bolts, Federal-Mogul hypereutectic pistons and rings, and a stock replacement oil pump. Many other stock parts, including most of the stock fasteners, from the core engine were reused as they were in good condition and only required a thorough cleaning.

For all of the machine work and dyno testing for the Battle of the Titans series, we will be working with Johnson Machine Service of Monrovia, California, which has been building quality race engines for decades. JMS's impressive facility offers a knowledgeable and helpful staff, quality machine work, a DTS dynamometer, and very reasonable prices. So sit back and see how we made the 360 a contender. You'll have to wait till the November issue's final installment for dyno results, though, as we're keeping them a secret even from the rest of the staff until they've completed the Ford and Chevy entries in our Titans shootout.

Cylinder HeadsThe most significant factor in horsepower production for any engine is the cylinder head. Because cast-iron production cylinder heads were mandated, our choices were limited. We debated using late-model production Magnum heads as well as Mopar Performance's big-valve Magnum RT castings but found both to be cost-prohibitive thanks to the need to update to a specific valvetrain (the Magnum engines were the first Mopar V-8 engines to incorporate a stud-mounted rocker arm in place of the ubiquitous shaft system). Also worth taking into consideration is the intake manifold selection available for the Magnum cylinder heads. Since we were mandated to use a dual-plane intake, the only offering is a low-performance dual-plane offered by Mopar Performance best suited to towing duty. The best remaining alternative was a 360 casting rebuilt by Aerohead with 2.02/1.60 intake and exhaust valves. While not as good on the exhaust side as some later-model castings, mid-'70s 360 smog heads feature greater cross-sectional area through the pushrod restriction. Also guiding our choice is the fact that these heads are readily available by mail order from Aerohead Racing. Aerohead offers 360 castings with 2.02/1.60 stainless valves, a three-angle valve job, hydraulic valve springs, 7-degree locks, bronze guides, and chrome-moly retainers for only $499 a pair plus shipping. An additional 100 bucks gets you the 915/587 castings that purportedly have a slightly larger intake port volume. We opted for the 587s and specified hydraulic-cam valvesprings able to accommodate up to 0.580-inch lift for no extra charge.

Bump And Grind: Cam SelectionA hydraulic flat-tappet cam is the name of the game here, so revs will be kept below 6,500 rpm, fitting nicely with our stock cylinder heads. Crane Cams came through with an off-the-shelf hydraulic grind that on paper seems pretty lumpy. We opted for enough lift to assist with torque production and enough duration to crutch the limited flow of the stock cylinder heads.

Camshaft SpecsManufacturer: Crane CamsPN: 694571Grind number: H-312-2Advertised valve lift: Intake/exhaust 0.528/0.552 (1.5:1 rockers)Advertised duration: 312/322 degreesDuration at 0.050-inch lift: 242/252 intake/exhaustInstalled intake centerline: 103 degreesLobe separation angle: 108 degrees

360 Mopar Parts and Prices
Mfr. Description PN Price Source
Aerohead 360 heads call $599.00 Aerohead
Edelbrock Performer 7576 234.95 Summit
  RPM Air-Gap      
Federal Mogul Kit Pistons H116 CP 433.95 PAW
  Rings E-377K (39.00 upgrade)  
  Rod bearings 2130CP (9.00 upgrade)  
Federal Mogul Main bearings 4999   PAW
Mellings Oil pump M72 22.95 PAW
Cloyes Timing chain PAW-103 29.95 PAW
Crane Cams Hydraulic cam 694571 209.95 PAW
  Hydraulic lifters 99278 93.95 PAW
Pioneer Rod bolts   20.56 JMS
ROL Gasket set 31030 32.95 PAW
JMS Machine work   705.00  
Milodon Oil pan 30740 104.95 Summit
Total     $2,522.11  
Machine Work by JMS
Procedure Cost
Steelabrait and Magnaflux block $75
Bore and hone 120
Deck block 120
Install cam bearings 25
Grind and polish crank 60
Resize rods and press fit pistons 80
Balance assembly 125
Intake manifold milling 100
Total $705
SOURCES
Aerohead Racing Components
8621 Southeastern Ave.
Indianapolis
IN  46239
Hooker Headers (A Division of Holley)
N/A
8-00/-Hol-ley1
holley.com
Demon Carburetion
Dahlonega
Ge
7-06/-864-8544
barrygrant.com
Johnson Machine Service (JMS)
724 E. Huntington Dr.
Monrovia
CA  91016
Crane Cams
530 Fentress Blvd.
Daytona Beach
FL  32114
3-86/-252-1151
N/A
www.cranecams.com
Milodon Inc.
20716 Plummer St.
Chatsworth
CA  91311
818-407-1211
Edelbrock
Dept. 5.0
2700 California St.
Torrance
CA  90503
310-781-2222
www.edelbrock.com
Performance Automotive Warehouse
Chatsworth
Ca
ARGET="_new">www.pawinc.com
Federal Mogul
26555 Northwestern Hwy.
Southfield
MI  48034
248-354-7091
www.fmperformance.com
Summit Racing Equipment
P.O. Box 909
Akron
OH  44309
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