We've finally reached a point with our Diplomat police car where we can use a couple hundred more horsepower. Instead of diving into the inner sanctum of the 318 now residing between its framerails, we opted to stick a slightly used 360 we had laying around into the interceptor. The 360 is from another project car of ours and features a 10:1 compression ratio, an otherwise stock bottom end, a fairly aggressive hydraulic flat-tappet cam, and a pair of mid-'70s 360 smog castings outfitted with 2.02 intake valves. Equipped with an Edelbrock Performer RPM Air Gap intake manifold and a 750-cfm Demon carburetor, this little gem knocked out 418 horses and 443 lb-ft of torque on a conservative (stingy would be a better word, actually) dyno. The engine is stout enough to power our '68 Barracuda project car into the high 11s at 114 mph. So it's definitely up to the task at hand. But we made a couple of changes to the 360 to make it more compatible with the girth of the '89 M-Body. The cam would have to go, as it didn't pull enough vacuum at idle to run the power accessories, and believe us when we say a 3,800-pound vehicle needs a lot of braking power to haul down from extra-legal speeds. in its place went a mild Crane hydraulic to boost low-rpm torque production. Also, all of the accessories including the intake with Q-Jet carb would be swapped over to the new engine, as well as the restrictive exhaust system. Baring any complications with lean-burn compatibility, the Q-jet would remain. The Dippy would then be chassis dyno tested with the old system and then retested with the new high-flow system to demonstrate the benefits of a good high-performance exhaust system.

Lean-Burn Sucks
No mincing of words necessary. With the hi-po 360 installed between the fenderwells, the lean-burn system wouldn't run right to save its life. Timing changes just didn't seem to make any difference in the way it ran. In fact, the car felt outright flat in the power department. The decision was made to address the ignition first. so we called our buddies at Glendora Dodge for a Mopar Performance electronic-ignition system that comes complete with an orange ECU, a vacuum-advance electronic distributor, and a wiring harness to tie it all together. Next on the chopping block was the carburetor. We were never quite at ease with the feed-back Quadrajet perched on the Diplomat's intake manifold, and it ran poorly enough to give us an excuse to try the 800-cfm Competition Thermoquad that's been taking up space in our garage. Plus, the TQ just looks right.

The Department of Corrections
In our May installment of Stealth Bomber, we ommitted listing the vendors involved, so here they are.

  • Just Suspension
  • Fairfield, NJ
  • (973) 808-0066

  • Koni Shock Absorbers
  • Hebron, KY
  • (859) 586-4100

  • Sleeper Suspension Development
  • La Verne, CA
  • (909) 392-8886

Engine Specs
Displacement: 365 ci
Compression Ratio: 10:1
Pistons: Federal-Mogul TK hypereutectic pistons

Cam specs: 216/228-degrees duration at .050-inch valve lift, .484/.512-inch lift with Crane 1.6:1 ratio rocker arms (.454/.480 with 1.5:1 rocker ratio), 112 -degree LSA

Cylinder heads: Aerohead reconditioned "578" castings with 2.02/1.60 valves

Induction: Factory cast-iron spread bore with 800-cfm Carter Thermoquad carburetor

Exhaust: Factory exhaust manifolds, 3 catalytic converters, single 2-inch exhaust

SOURCE
Glendora Dodge
9-09/-451-0022
B&M Racing & Performance Products
9142 Independence Ave.
Chatsworth
CA  91311
818-882-6422
Holley Performance
Bowling Green
KY
2-70/-781-9741
www.holley.com
Crane Cams
530 Fentress Blvd.
Daytona Beach
FL  32114
3-86/-252-1151
N/A
www.cranecams.com
Milodon
2250 Agate Ct.
Simi Valley
CA  93065
805-577-5950
www.milodon.net