Chevrolet - GM ROCKET BLOCKS WITH WET OR DRY SUMP
     This cast iron block is precision machined and does not require additional “blueprinting” to correct production tolerances. All block dimensions are machined to +/- .001”. The Dry Sump and one of the Wet Sump versions have been discontinued by GM and are no longer available from them.
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 GM ROCKET BLOCK DESCRIPTION
22551657 GM Rocket Block/9.025” Deck Height/2.45” Main Bearings/Dry Sump This block has been discontinued.
 22551659 GM Rocket Block/9.325” Deck Height/2.65” Main Bearings/Dry Sump This block has been discontinued.
 22551788 GM Rocket Block/9.025” Deck Height/2.45” Main Bearings/Wet Sump
 22551790 GM Rocket Block/9.325” Deck Height/2.65” Main Bearings/Wet Sump This block has been discontinued.
      GM Performance Parts has introduced a new small block V8 designed specifically for maximum-effort competition applications. The new Rocket Block is based on the proven GM corporate (Chevrolet) small block V8. Designed in conjunction with top racing teams, this heavy duty cast iron block provides outstanding performance at reduced cost.
     GM Performance Parts launched the Rocket Block project to meet the needs of stock car racers, sprint car teams, drag racers, and road racers. This "clean sheet of paper" design solves the shortcomings of production based blocks used in competition
     The GM Rocket Block has a maximum recommended displacement of 455 cubic inches (tall deck version).

     Major components (cylinder heads, crankshaft, ext.) are interchangeable with the Chevrolet small-block V8.
     The Rocket Block’s camshaft is raised .391” for additional crankshaft clearance. The main oil gallery is to the right of the cam.      The Rocket Block’s pan rails are spread .800” to clear a long stroke crankshaft.
GM Rocket Block
     The rear of the block has provisions for oil inlet and lifter valley scavenge lines.      The steel rear main bearing cap uses a two-piece rear seal.

 ROCKET BLOCK’S ADVANCED ENGINEERING FEATURES:
Relocated Camshaft: Compared to a production Chevrolet small-block, the Rocket Block’s camshaft is raised .391” (4.912” camshaft-to-crankshaft centerlines). This relocated camshaft will clear a 4.125” stroke crankshaft without interference, eliminating the need for a small base circle cam when using a long-stroke crankshaft. Camshaft drives are available from aftermarket sources (for example, Cloyes 9-3100 set sprockets and 9-131 roller chain, Jesel belt drive, etc.).
Big-Block Camshaft Bearings: The Rocket Block uses GM big-block V8 cam bearings. These larger cam journals allow the camshaft base circle diameter to be enlarged, thereby enhancing camshaft strength and reliability. Flat tappet and roller cores are available from aftermarket camshaft companies.
Relocated Oil Pan Rails: The Rocket Block’s oil pan rails are spread .800” (.400” per side) compared to a production GM small-block V8. These pan rails will clear up to a 4.125” stroke crankshaft in tall deck blocks with minor modifications.
Revised Oiling System: The Rocket Block has a “priority main” lubrication system that directs oil to the main bearings before the cam bearings. The main oil gallery is located next to the camshaft tunnel; oil can be pumped into this gallery through a boss above the timing chain cover or through the bellhousing flange behind the No. 7 cylinder. In wet sump versions, the rear main bearing cap is machined for a standard oil pump.
Optional Deck Heights: The Rocket Block is available with two deck heights: 9.025” (standard small block V8) and 9.325” (.300” taller than production). Both versions have .625” thick decks.
Siamesed Cylinder Walls: The Rocket Block's extra thick siamesed cylinder barrels provide a minimum .275” wall thickness with a 4.125” bore. The cylinders can be safely bored to 4.190” diameter. The outer jacket walls are scalloped to enhance coolant flow around the siamesed cylinders. The Rocket Block retains the Chevrolet small block V8’s 4.400” cylinder bore centerlines.
Reinforced Deck: The Rocket Block has a minimum .625” deck thickness, regardless of the deck height specified. The head bolt holes are blindtapped, and the head bolt bossed are freestanding to minimize cylinder bore distortion. The Rocket Block has a standard GM small block head bolt pattern.
Maximum Displacement: Maximum recommended displacement for tall deck Rocket Blocks is 455 cubic inches (4.190” bore x 4.125” stroke). Maximum recommended displacement for standard deck Rocket Blocks is 414 cubic inches (4.190” x 3.750” stroke).
Steel Four-Bolt Main Bearing Caps: The three center main bearing caps have splayed outer bolts. The two bolt front and rear bearing caps are retained with studs. Blocks with standard deck heights use 2.45” (350-type) main bearings; tall deck blocks use 2.65” (400-type) mains.
Dual Starter Mounts: Both sides of the Rocket Block are drilled and tapped for starter bolts. Mounting the starter on the left (driver’s) side of the block provides additional clearance for an extended oil pan. The block-mounted oil filter is eliminated; a remote filter is recommended.
Precision Machining: The Rocket Block is precision machined to blueprint specifications and does not require additional “blueprinting” to correct production tolerances. All block dimensions are machined to +/- .001”.
Engine Mounts: The Rocket Block retains all production bosses for side and front engine mounts.
Fuel Pump: The Rocket Block has provisions for a block-mounted mechanical fuel pump. When using a mechanical fuel pump, a .200” longer fuel pump pushrod is required.
Rear Main Bearing Seal: The Rocket Block uses a pre-1986 two piece small block rear main bearing seal. Tall deck blocks with 400-type main bearings require a special rear main seal (Fel-Pro #2909).
Special Parts: Many Chevrolet small-block V8 components are interchangeable with the Rocket Block, including cylinder heads, oil pump, valvetrain, etc. Distributors are also interchangeable; however, the distributor drive gear must be raised to compensate for the Rocket Block’s raised camshaft. Tall deck blocks require intake manifold spacers or an intake manifold with thicker flanges to accommodate the increased block height. Pushrod length will depend on the particular cylinder heads and valvetrain used. Other special Rocket Block components include a large journal camshaft, camshaft drive, oil pan, and fuel pump pushrod as noted previously.
Technical Notes: Depending on components used, bottom of bores and oil pan rails may require notching and additional machine work for connecting rod and counterweight clearance. Mounting the starter on the left (driver’s) side of the block provides additional clearance for an extended oil pan. If the block-mounted oil filter is eliminated, a remote filter is required.

 SPECIFICATIONS:
Part Number Deck Height Oiling System Main Bearings Bore Diameter
22551657 9.025”(std.) Dry sump 2.45”(350-type) 4.000”-4.190” Disc.
22551659 9.325”(tall) Dry sump 2.65”(400-type) 4.125”-4.190” Disc.
22551788 9.025”(std.) Wet sump 2.45"(350-type) 4.000”-4.190”
22551790 9.325”(tall) Wet sump 2.65”(400-type) 4.125”-4.190” Disc.