When we last pulled our street 360 combo off of the dyno, our astoundingly stock 360 (lifted from a wrecking yard '79 Cordoba) pulled down an impressive 390 horsepower at 5400 rpm, and torqued-up to the tune of 404 lbs/ft. at 4600 rpm. The combo was bread-and-butter plain, fitted with a Comp Cams 280 degree Magnum hydraulic cam, 10:1 TRW Hypereutectic pistons, an Edelbrock Torker II manifold, and Hooker 151/48-inch street headers. Inside the stock .030-over '79 block were stock rods, stock cast iron crank secured with stock bolts, and a stock windage tray. On top was the original '79 Cordoba smog heads (which we showed in detail how to effectively port) dressed with the stock rockers on the stock shafts, with stock pushrods. Up top, a stock Chrysler Thermoquad mixed the air and fuel, while a stock distributor fired the mixture through a regular stock-type Chrysler electronic ignition.
In the last installment of...
In the last installment of our "Double Take 360" we made over 390 horsepower and 404.8 lb/ft of torque. We were gunning for more this time, and decided to open the bottom end for some minor durability mods.
Plain as it all was, with our highly effective modified smog heads working with a well matched cam and induction, this mill delivered more power than many commonly sold, more exotic engine combos. How about ZZ4 or LT 4 Chevy 350 crates with Aluminum heads and roller cams, boasting 355 and 360 horsepower respectively? The Ford GT-40 A351 bracket race motor and its 385 horsepower with 16 degrees more intake duration and 26 degrees more exhaust, not to mention the aluminum leads? Have we broken any illusions here?
Yeah, we figured our street 360 was making pretty good power already, but our intention from the beginning was to take the same basic combo up a few notches, while retaining a streetable set up. We decided to keep the rest of our combination as it was, and step up in the area of the cam and valvetrain. The only question was what approach to take in making the change. The most obvious route would be to simply go to a bigger hydraulic cam. Our 280-degree Comp grind was a full 10 degrees shorter than the cam found in the Mopar Performance 380 horsepower crate engine. Going up to the Comp 292 Magnum hydraulic cam would no doubt add to our already strong horsepower numbers, but for true street use the trade-off in drivability and idle quality would be noticeable. The fact is that the 280-degree Comp Magnum is just about the ideal hot-street/strip hydraulic cam if you really want to live with it on a daily basis. We just weren't prepared to give that up for a few more top end ponies.
Just the bare essentials were...
Just the bare essentials were going to be added for peace of mind in the form of a Milodon main stud kit to replace the original junkyard bolts. Our stock windage tray relies on the factory main cap bolts for mounting, so we made the swap to a Milodon tray designed to work with their #81186 stud kit.
Solid Performance
We figured if we were going to swap out our current cam in the quest for more power, we'd have to go with something trick to see meaningful gains in power without a large trade-off in drivability. What we wanted was the high rpm stability of solid lifters, a relatively short "seat," or overall duration, but lobes that open the valves at a truly radical rate. We found what we were looking for in the lobe specs pages of the Competition Cams catalog. The Comp Tight Lash solid profiles are no-compromise, full-race endurance engine lobes designed for maximum valve acceleration off the seat. The most aggressive of these are listed as .875-inch minimum lifter diameter profiles. Speaking to Comp's chief cam designer, we were told these lobes were pushing it to the limit with a .875-inch diameter lifter (everything had better line up perfectly), but are an ideal match with a Mopar .904-inch tappet.