Hands On

The Goodwrench crate motor is an affordable small-block that could rustle up 285 hp if all you did was bolt it in between the framerails with a set of headers and a four-barrel carb. We intend to do much better.

The Goodwrench crate motor is an affordable small-block that could rustle up 285 hp if all

Despite what the boo-birds on the Internet think, there are hundreds of small-block Chevy stories yet to be told. This is one of 'em. Car Craft staff meetings are great places for "what-if" musings. The question at one such meeting was whether we could make a survivable 500 hp from nothing more than a brand-new Goodwrench crate engine, a budget camshaft, and a single-plane intake--topped with a simple nitrous system. Right there on a yellow legal pad was born the Saturday Night Slayer.

For the benefit of the few car crafters who may not know about the Goodwrench engine, it's only the most affordable crate-replacement 350ci small-block Chevy ever offered by GM. This engine comes with four-bolt mains, a two-piece rear main seal cast crank, cast pistons, a very low static compression, iron heads, and a very-short-duration, flat-tappet camshaft. It is the essence of the original small-block Chevy, and the best part is it's ridiculously affordable. We got ours from Scoggin-Dickey Parts Center in Lubbock, Texas, for $1,500 plus shipping. You could probably rebuild a small-block for that price, but who would give you a three-year, 100,000-mile warranty and all-new parts? GM does if you leave the engine stock. Our plan killed those warranty fantasies as soon as the engine cleared its crate.

Did we mention this engine has no compression? While GM claims 8.5:1 (Scoggin says 8:1), we measured 7.9:1. That's the reality, and it allows this motor to run on moose piss for fuel, but it's hardly conducive to excellent performance or mileage. We've had some experience with these engines, and each one we've beat on has survived to live a long, prosperous life. This latest effort plans to tax that longevity reputation to the max with a hefty whiff of nitrous.

While most guys would just bolt this Goodwrench engine in the car just the hear it run, we tore ours apart. The first thing we did was yank the heads and bolt in thinner head gaskets. We used a set of Fel-Pro, rubber-coated, steel-shim gaskets that are only 0.015 inch thick, raising the compression to a slightly better 8.2:1.
While most guys would just bolt this Goodwrench engine in the car just the hear it run, we
Next on the replacement list was the camshaft. The stocker is just too mild for performance use, so we plugged in a Summit, flat-tappet, dual-pattern, hydraulic cam. In keeping with our mac-and-cheese budget, we reused the stock lifters, too, after coating the lobes and lifter faces with break-in lube.
Next on the replacement list was the camshaft. The stocker is just too mild for performanc
After checking the camshaft, we discovered it was 4 degrees late with a 113-degree intake centerline. This required drilling a 13⁄32-inch (0.406) hole in the backside of the stock cam gear just deep enough to seat the bushing. A 4-degree offset bushing placed the cam at the 109-degree centerline.
After checking the camshaft, we discovered it was 4 degrees late with a 113-degree intake

The plan is to make 500 hp with minimal cash. That sounds simple enough, but it's a bit more challenging on the execution side. The easiest way to increase the compression is with cylinder heads, but that slaps the budget around a bit, so for this first effort we decided to retain the anemic 1.94/1.50-inch valve heads. A camshaft, however, was certainly within our modest means when we found a Summit flat-tappet hydraulic with appealing specs priced at barely more than $50. We didn't even need to buy lifters because we could use those that came with the engine. We're still smarting from the flat lobes used during a recent engine build, so we opted for 5 quarts of Comp's new Break-In 10W-30 that ironically cost almost as much as the camshaft. That's the price of ensuring cam survival these days, as 5 quarts of regular oil and a can of EOS is virtually the same price.

We also included a few other necessary pieces to complete the engine, such as a harmonic balancer, a carburetor, an ignition, and a set of headers. These invisible pieces can drive up the price of a complete engine and are often overlooked. In a second installment, we intend to bolt this motor into our Orange Peel '66 Chevelle to evaluate how quick we can make this entry-level power burner run while also revisiting some basic performance- tuning recommendations that anyone can do. But first, let's get into the game by loading up our Saturday Night Slayer and hitting the button.

Cam Specs
Camshaft	Duration at 0.050	Valve Lift	lobe-separation angle
Stock cam, int.	195	0.390	114
Stock cam, exh.	202	0.410
Summit, int.	224	0.465
Summit exh.	234	0.485

Tuning Notes

NOS recently changed its tuning recommendations based on input from a recognized nitrous-tuning expert. Note also that there are different ignition timing specs depending on combustion efficiency. We took this to mean the combination of compression and quench. We used the low-efficiency number because of our engine's weak compression. We've listed only the two tune-ups we tried and changed the NGK spark plug recommendation to Autolite heat ranges for the plugs we used. Your actual plug part numbers will depend on the engine application.

Nitrous HP	Combustion Efficiency	Ignition Timing	Spark Plug	Fuel/Octane
150	Low	29	AR133	100+
150	Medium	27	AR133	100+
150	High	25	AR133	100+
200	Low	24	AR132	110+
200	Medium	22	AR132	110+
200	High	20	AR132	110+

To make the most of our test day, we skipped the entry-level baseline but found an earlier test of this engine using the stock cam, Q-jet intake, a 750-cfm Q-jet carburetor, and a set of 1-5/8-inch headers that produced 348 lb-ft of torque and a wheezy 254 hp. After we added the new cam and intake, we were ready for our normally aspirated baseline. We expected the bottom end of the curve to be weak, as we were adding 29 degrees of intake duration and a single-plane intake manifold. Despite those changes, the Goodwrencher delivered nearly 50 lb-ft over the original package at 2,500 rpm and twisted 355 lb-ft of torque at 4,100 with 332 for horsepower at 5,500. We chose a single-plane because it promised to work well with nitrous, but a good dual-plane such as a Holley or an Edelbrock Performer RPM would pump the torque as much as 20 lb-ft with no significant loss of peak horsepower. This would be the best choice if nitrous were not part of the equation.

The new cam’s added lift required checking the valvespring installed height to ensure the coil springs wouldn’t go into coil bind or that the retainer wouldn’t crush the valve seal under max lift. We had sufficient clearance, so we didn’t have to change springs or machine the head.
The new cam’s added lift required checking the valvespring installed height to ensure the
We used a set of Summit intake gaskets to bolt on the Weiand X-celerator single-plane intake. We chose the single-plane mainly because it would produce the highest peak horsepower. We also bolted on a used Holley 750 mechanical-secondary carb we rescued from the swap meet.
We used a set of Summit intake gaskets to bolt on the Weiand X-celerator single-plane inta
The NOS Cheater nitrous system includes everything you need (just add nitrous and stir) to make big power. Pay attention when installing the plate. The correct orientation is with the NOS logo pointing up. Install the plate upside down, and the engine will not be happy when you squeeze it.
The NOS Cheater nitrous system includes everything you need (just add nitrous and stir) to

We were pleasantly surprised with the torque and horsepower numbers from the normally aspirated combination, but our goal was 500 hp, so it was time for the squeeze. Nitrous Oxide Systems has recently changed its tuning recommendations for all its nitrous kits by leaning the overall air/fuel ratio. For example, older NOS Cheater kits recommended an 0.063 nitrous jet with an 0.071 fuel jet for its 150hp combination. But the new kit uses 0.063 jets for both fuel and nitrous while maintaining the same 5- to 6-psi fuel pressure recommendation. NOS also offered new insight into how much timing should be retarded. The new tune offers timing retard recommendations based on three levels of combustion efficiency (low, medium, and high), with the highest timing allowed for low-efficiency combos. Since our Goodwrench engine barely pushed 8:1, the recommendation for a 150hp shot was to pull the timing back to 27 degrees.