Section 02 - Block Basics

Block Basics – Section 2 Section 02 - Block Basics 2.0 Small Block 330 & 350 Block Key Differences. The key differences between the 330 and 350 are the 350’s larger bore and the Generation 1 Cast Iron Small Block V-8 Facts 330’s forged crank. General. In 1964 Olds replaced their small block 215 V8 with 1964 – 1966 Valve Lifter Angle. All 1964–1966 blocks used a a cast iron block of completely new design. The 330 V-8 different valve lifter angle of attack on the cam (45). Thus shared none of its engine block architecture with that of the 1964–1966 330 blocks CANNOT USE 1967 AND LATER 215 V-8 and the 225 V-6 sourced from Buick. The engine CAMS. All 1964–1966 cams WILL NOT WORK in 1967 and was no longer aluminum, but cast iron, as weight became later blocks. Later blocks used a 39 lifter angle. Blocks with less of a factor with the engine going into both the larger a “1” or “1A” cast up near the oil filler tube used the 45 lifter mid-sized F-85s, Cutlasses and the full-size Jetstars angle and should be avoided, if possible. introduced in that year. The engine was designed as a replacement for the 215, but was cast iron and enlarged in Early 330 Rocker Arms. The first run of 330 blocks was anticipation of the growth in size of the mid-size cars, where equipped with rocker arms similar to the previous 394 block it was to be primarily used and as the workhorse for the that traces its heritage back to 1949. These rockers had a entry-level full sized vehicles. Horsepower and torque for the shaft that ran the entire length of the head to which the 330 allowed for the engine to be installed in the full-sized rockers were attached, similar to the Aluminum 215 and Jetstars as the base engine and in 4-barrel form as the Buick engines. This is a very stable setup, but it weighs upscale powerplant. In 1968 the engine was enlarged to 350 more and was more expensive to manufacture than the cubic inches and used in 2-barrel and 4-barrel form. stamped steel rockers that are common on a 1965-1989 Olds. 1964 engines up to the engine serial number 034275 This engine was offered from 1964 through 1975, when it have these heads and should be avoided where possible. was replaced by the Generation 2 small block. This engine was offered in five flavors with displacements from 260 to Bore/Stroke. The small block does have the advantage of an 403 cubic inches. (See below). excellent bore/stroke ratio and nice, easy to oil, main bearing sizes. As such it will rev to 6500 without spinning Not So Thin Wall Casting. The 330/350 small block was bearings if proper oiling is used. It makes more than enough designed to be a “thin wall’ cast design, but because casting torque for "A", "X" and "G" body performance. cores did not have the technology we do today, Olds built a little extra in the walls of the early blocks. Thus, blocks from Bearing Diameter. The small block uses bearing sizes 1964 to 1977 can easily be bored to 0.060”. All 330s can similar to small block Chevys and thus has less bearing come out to the equivalent to a 0.060” over 350 which, for surface to oil, important as the engine rpms rise. The the 330 is 0.1815” over. We have seen 330/350s taken out connecting rod journal size is 2.125”; the main journal size is to be able to take a 425 piston (4.125”), but the block should 2.5000”. be sonic tested first. Frankly, the largest all this boring is Crankshaft. The 330 used a forged crankshaft and all others going to do is take your small block to 360 cubic inches, a did not. The forged crank will take more abuse, however the big gain in a 330, but only 10 cu. in. in a 350. If you are cast nodular iron crank in the early 350 seems to hold up looking for more cubes – go to the big block. In our opinion, well in performance work. Significant in the forged versus except for the 330, over boring should only be used to clean cast crank is that the 330 uses a different flywheel bolt up the bores. pattern than the 350. Thus, 330 flywheels and flexplates are only available in junkyards or from suppliers like Mondello and ATI. If you are scrounging a 330 block for the crank, take the flexplate too. (See the enclosed chart for the appropriate parts numbers). Pistons. Pistons in all 260 through 403 engines (except the diesel) are cast, and use the same construction. As such, they have the same pin position/size, with only the piston bore as different. This allows overbored 330s to accept stock or aftermarket 350 pistons. However, the 330-350 blocks cannot be overbored to accept Generation 2 403 pistons, since the 403 block is siamesed. 350 diesel pistons are of a different construction and pin size. Shared Components with the Big Block. The small block engine shared many of the components of the 400/425 big block that would be introduced a year later. This included The famous “Ram Rod 350” – the 1968 W-31 package. the camshaft, rocker arms and springs, the cam bearings, The air scoops fit under the bumper. It was also offered in 1969. the distributor, the starter, oil pan and front cover and water (This system was used on the 400 W-30 and W-32 as well). - 11 - Block Basics – Section 2 pump. The cylinder heads will bolt on, but they contain much supply and so as to use existing tooling. (Olds was the larger ports and valves, and in most cases, these largest selling GM brand at the time). It was superseded components hurt low-end performance (see W-31 engine by the 307 in 1982. Its small 3.495" bore, but standard option, below). With machining, the cranks could be small block 3.385" stroke kept it over square, but interchanged as they are the same length, (the 330/350 severely restricted the intake valve size and resulted in utilizes 2.12" rod journals versus 2.50"; and 2.50" mains poor combustion chamber swirl12. Contrary to versus 3.00"), but there is little reason to do so as it is far expectations, it was a very inefficient engine at a time more appropriate to select the block for the engine size when fuel efficiency was paramount. The 260 did not desired. A 403 with the 3.975" 455 crank would be 480 cu. come with a 4 bbl manifold. 307 heads and intakes can in. with a 0.030" overbore, however. Interesting. be fitted, but the bores will have to be notched on the intake side. Generation 2 Cast Iron Small Block V-8 Facts . The 307: The 307 was the last Olds V8. It was actually General. This engine though so similar to the previous quite a good engine, and with the right parts can make original 330-350 in size and block design, is considered a excellent HP. It is a true 5.0 Liter engine, with a bore of Generation 3 engine because of its "windowed" main 3.800" and the 3.385" stroke. Its "windowed" main bearing webs. This change is found in all the 260, 307 and journals are its weak point. If you are looking for big 403 designs and the 350s constructed after 1976. All small horsepower from a small block, utilize a 330-350. 330 blocks after 1976, including the diesel, used ½" head bolts and 350 heads can be fitted, but the cylinder bores will 7 rather than /16". likely need to be notched for intake valve clearance, especially if the W-31 style 2.00" (or larger) valves are Thin Wall Casting. This block is truly thin wall cast, and installed. weighs as much as 25 lbs less than 1964-1976 engines. None of these blocks should be overbored more than . The 330: The 330 was the first "thin wall" cast Olds 0.030". block. It came in two flavors: an early 45 lifter angle block and a 39 lifter angle block which was common to Windowed Mains. From 1977 onward all small blocks, all later Olds engines. The 45 lifter angle block requires including the 403 were produced with “windows” in the main special camshafts and is not recommended, though if bearing journal area, which obviously affects strength and you are restoring a 1964-1966 Cutlass, cams are longevity under hard use. (Diesel blocks are an exception). available for this engine. (The original 1964 442 did For 403 owners, there are rumors of solid main journal utilize this block). 403's, cast using the pre-1977 technique. Supposedly 2500 solid main 403's were produced in 1977 - used in the large . The 330 followed the Aluminum 215's "under square" Buick and Olds wagons. A solid main journal 403 can be practice, with a bore larger than stroke at 3.9385" x determined by looking at the block casting number. 403 3.385". The 330 and 350 share many common pieces, except for the crank, which is forged in the 330. This Block Casting Numbers: 557265-4A, 553990-4A, and requires a different flywheel/flexplate. The 1964-1966 554990-4A are supposed to have no “windows”. With only 2500 produced, these are a rare but beneficial find.

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