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305 Small-Block Build - Questions and Answers - What's Your Problem?

Have questions or concerns? Jeff Smith has answers.

Smog-Legal Monte
Al Harris; Pasadena, CA: I need your advice on an engine rebuild I'm having done soon. In 1993, I purchased a Chevy crate engine PN 10067353 to put in my '85 Monte Carlo SS. What would be your suggestion for a camshaft? I want to keep it smog-legal. What would be your horsepower and torque estimate for the current parts I have accumulated? I have an Edelbrock intake (PN 3701), exhaust (PN 68793), and World Products S/R Torquer heads (PN 042670-1). All I'm looking for is a slightly warmed-up daily driver that will pass the smog test.

Jeff Smith: Al and the rest of the long-suffering car crafters who live in high-population-density areas in California are burdened with proving emissions legality when attempting to build a '76-or-later street machine like his '85 Monte Carlo. Happily, there are several recommendations we can make to help complete the buildup. The crate engine Al referenced is the 350ci Goodwrench replacement engine that's rated at 195 hp but can make as much as 250 hp with a good intake and headers. This engine uses cast pistons squeezing 8.5:1 compression and is based on the older, two-piece rear main seal-style cylinder block. This engine makes a great starting point for a mild small-block Monte.

The stock cam that comes in the Goodwrench engine is very mild with 194/202 degrees at 0.050 with equally mild 0.383/0.401-inch lift numbers. Since you already have the Edelbrock intake and exhaust, you might consider running the Performer-Plus flat-tappet camshaft. The specs are quite a bit stronger at 204/214 degrees at 0.050 with 0.420/0.442-inch valve lift numbers with a lobe-separation angle of 110 degrees. That cam actually has a California Executive Order (E.O.), which makes it legal to use in emissions-controlled small-blocks up to 1985. That means Edelbrock has already done the testing to confirm that this camshaft will allow you to pass the typical California tailpipe emissions test.

Because Al's Goodwrench engine is a two-piece rear main seal engine, it's not equipped with the changes made to the later, one-piece rear main seal engines that would allow you to run factory-style hydraulic roller camshafts. You could still convert to a hydraulic roller camshaft, but it would be more expensive because you would have to purchase the retrofit aftermarket hydraulic roller lifters. These are much more expensive than standard production hydraulic roller lifters. Given that option, we spoke to Jim Hall at Tuned Port Induction Specialties (TPiS), a company that has loads of experience building '80s- and '90s-style performance engines. Hall recommended the company's ZZ8 camshaft that specs out with 212/212 degrees of duration with 0.483/0.483 inch of valve lift and a lobe-separation angle of 114 degrees. He says this will idle at 19 inches of manifold vacuum. TPiS built an LT4 engine with that ZZ8 cam, CNC-ported LT4 heads, and headers that made 430 hp. Your S/R Torquer heads are not quite as strong, so you could expect around 400 hp, which would make your Monte SS a great little cruiser.

You might even want to consider a mild upgrade to the heads while you're at it. The World Products S/R Torquer heads are perhaps the best-flowing, iron, direct-replacement castings on the market, but even these heads can use some help. The hot ticket is to improve the exhaust flow of the heads with a little pocket porting. All production-based small-block Chevy heads tend to be weakest on the exhaust side of the flow curve. A mild amount of bowl work directly underneath the intake and exhaust seats always results in the most amount of flow improvement for the least amount of labor invested. If you're thinking of doing the work yourself, check out past stories on home porting heads to get the technique. Or you can call our pals at Slover Porting in nearby Sun Valley, California, and they can do the work for you at a very reasonable price.

If your Monte needs a catalytic converter, California has also made life a little more difficult for those car crafters driving '80s and '90s OBD-I emissions-controlled vehicles. In 2009, California outlawed the use of less expensive, nonapproved aftermarket catalytic converters. Apparently, these cheaper catalytic converters minimize the amount of precious metals such as palladium, platinum, and rhodium. I did some digging and discovered that MagnaFlow's parent company, Car Sound, makes an exempted replacement catalytic converter that is available in either direct replacement or universal applications. For the Monte, a California-legal, direct-fit four-bolt catalytic converter for the high-output Monte Carlo is MagnaFlow's PN 36440, and we found it on Summit Racing's website for the excellent price of $247.61. These cats are a little more expensive because they must contain a higher precious metal content since part of the California law requirement is that the manufacturer offer a five-year, 50,000-mile warranty.

In case you missed it, we also did a complete suspension upgrade on a Monte just like yours called "Upgrade a GM Coil Spring Car" (Feb. '10) in which we bolted on a bunch of Edelbrock suspension goodies to this G-body to turn it into a corner scorcher. The G-body is also an outstanding candidate for an LS engine swap. A 6.0L iron truck engine or perhaps even the popular E-Rod LS3 6.2L engine that makes 430 hp would be an outstanding swap. You could even retain the performance-oriented 200-4R overdrive automatic.

More Info

Edelbrock; Torrance, CA; 310/781-2222; Edelbrock.com

MagnaFlow Performance Exhaust; Rancho Santa Margarita, CA; 800/ 990-0905; Magnaflow.com

Slover's Porting Service; Sun Valley, CA; 818/768-0155

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