We pick up part two of our Chevy small block history in the early muscle car era. By the early 1960s the horsepower wars that would lead to the muscle car era were brewing and Chevy was not going to be left behind. What some call the second generation, but really is just the second era of the first generation of the Chevy small block engine would feature a 4.00 in bore and see numerous applications, options, and sizes.
The first of the production 4.00 in bore small blocks was the 327. The 327 utilized a 3.25in stroke and in base form was good for 210hp. This engine went in everything from taxis and trucks, to cars, and vans. In the right platform and with the right configuration the engine could make a whopping 375hp.
In 1967 probably the most well known of the small block Chevy’s would make it’s debut in the Camaro. Camaro owners who checked the L-48 option would get the high performance 350 making 295hp. The same engine would be available the next year in the Nova. By 1969 the 350 in high performance trim would get 4bbl Quadrajet carburetor, cast pistons, 4 bolt main, high flow heads, and an aggressive hydraulic cam. This upped the power to 300hp and torque to 380ft/lbs. When the emmisions regulations hit in the early and mid 1970s the L-48 350 would be used in the Corvette and many other cars with some what neutered performance due to a lower compression ratio (10.5:1) and emissions equipment.
The king of the muscle car era small blocks was the LT-1. (not to be confused with the LT-1 of the early 90s.) The LT-1 was available on the Corvette, Corvette ZR-1, and Camaro Z28 starting in 1970. The LT-1 made it’s mark buy using solid lifters, a Holley 780cfm four barrel, 11:1 compression ratio, high po camshaft, and an aluminum intake designed for the engine. The factory sold the engine as 360hp, although it was rated at 370hp, and the NHRA rated it as a 425hp engine. Under rating of an engine by the factory was pretty common through out the muscle car era and GM underrated with the best of them. This made LT-1 powered muscle cars very desirable because the insurance was not as bad as the big blocks but they still had potential to rule the streets.
By 1973 the muscle car era would come to a screeching halt with emissions regulations, an oil crisis, and a general recession. In 1973 a performance version of the 350 called the L82 was introduced. It would see a lower compression ratio of 9:1, a dual plane intake manifold, and four barrel quadra jet carb. As a result horsepower was down to 250hp. Part of this was the lowered compression and part was the new way the SAE measured horsepower with emissions and exhaust equipment in place. Either way it is hard to argue that the hay day of horsepower was over and it would take some twenty five years before automakers were turning out big horsepower again.
The 350 would live on as the staple of Chevy’s 4 inch bore V8 line up for another few decades in one form or another. Power continued to decline over the years from the factory but many aftermarket companies, engine builders, and racers still sought the 4 inch bore 350 because of it’s potential. With the restrictions for emissions removed the 350 was still a very capable, very durable, powerhouse.
Check back in a few days when we will finish out the first generation of the small block Chevy.