350 Engine - Packaged Performance

1 Though our 350 was sporting forged slugs, the basic premise can be applied to any stock short-block. Care must be taken to ensure adequate valve clearance with wilder cam profiles.

1 Though our 350 was sporting forged slugs, the basic premise can be applied to any stock

Having the most popular performance engine ever built, Chevy small-block owners are lucky indeed. Despite the introduction of the LS engine family (see Modern Mouse elsewhere in this issue), the original Mouse motor continues service in everything from street/strip machines to one-ton work trucks.

One of the keys to the success of the little V-8 is its versatility. Essentially, it can be tuned for almost any application. Obviously a Camaro owner looking to run in the 11s will choose a different combination than a truck owner looking to haul his favorite bass boat. The great thing about the Chevy is that despite the differences in the application, the basic short-block remains the same. The benefit of this is that just about any buildup, from mild to wild, can start with the very same block, crank, rods, and pistons.

2 Initially, the small-block was assembled with a factory hydraulic flat-tappet cam.

2 Initially, the small-block was assembled with a factory hydraulic flat-tappet cam.

To illustrate this fact, we decided to take your average 350 and subject it to four different performance packages. The idea was to start with a bone-stock engine, then step things up with the proper combination of heads, cam, and intake. The exercise started with an engine producing less than 300 hp but finished up with over 500. Though it is possible to exceed this power output with an engine displacing just 350 cubic inches, 95 percent of street/strip small-block buildups fall between the proposed power outputs.

Before getting to the particular combinations, it is important to cover something we call shifting the torque curve. Time was when the yardstick for a performance engine was 1 horsepower per cubic inch. Applied to our 350, that would equate to an even 350 horsepower. We know from experience that it is possible to greatly exceed this specific output; in fact, race motors have been known to more than double it. Most street (and strip) motors fall well short of dedicated race motors, achieving somewhere near 1.5 horsepower per cubic inch. The power output of the motor is a function of its ability to process air—the more air in (actually through) the motor, the more power out. Things like high-flow intakes, cylinder heads, and wilder cam timing naturally play a part, but so too does engine speed. Nearly all of the modifications to a stock motor increase the engine speed (rpm) where the motor makes peak power.

3 The baseline runs were made with a set of factory iron 882 head castings. The 1.94/1.5 valve package was more than adequate, but the 76cc combustion chamber reduced the static compression ratio.

3 The baseline runs were made with a set of factory iron 882 head castings. The 1.94/1.5

The downside to this shift in the power curve is that the sizeable gains offered in middle and upper portions of the curve eventually come with a loss in low-speed torque. Alas, there is no free lunch when it comes to maximizing power production. With that in mind, check out the different combinations and see which one might be right for you.

Test 1: Baseline—Stock 350 Chevy

Baseline 350 Engine Specs

• Short-block 350 Chevy flat-top pistons
• Heads: stock 882 iron 1.94/1.5 valves
• Cam: Stock hyd. flat-tappet {factory 180hp}
• Rockers: Stock
• Intake: Factory iron Q-Jet
• Carb: Factory Q-Jet
• Exhaust: 1-5/8-inch headers

Test 2: Stock vs. Ported Heads, RV Cam, and RPM Air Gap

Test 3: Stock vs. Procomp Electronics Aluminum Heads, Comp Cam, and RPM Air Gap

Upgrade 2, 350 Engine Specs

• Short-block 350 Chevy flat-top pistons
• Heads: Procomp aluminum 190cc heads {as cast} 2.02/1.6 valves
• Cam: Comp XE268H {0.477/0.480 lift, 224/230 duration, 110 LSA
• Rockers: Comp Roller 1.5
• Intake: Edelbrock Performer RPM Air Gap
• Carb: Holley 650
• Exhaust: 1-5/8-inch headers

Test 4: Stock vs. Airflow Research 195 Eliminator Heads, Comp Hyd. Roller Cam, and AFR Titan Intake

Upgrade 3, 350 Engine Specs

• Short-block 350 Chevy flat-top pistons
• Heads: AFR 195 Eliminator heads {Comp version} 2.08/1.6 valves
• Cam: Comp XR300HR {0.562/0.580 lift, 248/254 duration, 110 LSA
• Rockers: Comp Roller 1.5
• Intake: AFR Titan Composite Single-Plane
• Carb: Holley 950 HP
• Exhaust: 1-3/4-inch headers