Hardcore 509 Specs
Displacement: 509 ci
Bore x stroke: 4.500x4.000 inches
Compression: 9.5:1
Weight: 640 pounds
Cylinder heads: Iron Merlin 345 cc (PN 030630A-2), 119 cc
Valves: Manley 2.300/1.880-inch intake/exhaust
Head gaskets: Fel-Pro (PN 1017-1)
Balancer: Pro Race (PN 24264)
Carburetor: Hardcore 870 Hi Flow (PN 217-25133)
Intake manifold: Merlin single-plane (PN 063030)
Ignition: Hardcore HEI (PN 216-85306)
Wires: Taylor/Merlin 8mm
Cam: Crane hydraulic, 236/246 degrees duration at 0.050-inch lift, 0.553/0.571-inch lift
Valvesprings: 1.550-inch diameter dual
Rocker arms: 1.7:1 Crane/Hardcore roller rockers
Pushrods: Manley 4340 one-piece
Lifters: Speed Pro hydraulic
Timing chain: Manley Street Roller (PN 73168)
Valve covers: Merlin chrome (PN 070741)
Oil pan: Milodon (PN 30710)
Oil pump: Federal-Mogul
Block: Merlin II 9.800
Crankshaft: Scat/Eagle 4130 4.000
Connecting rods: Manley
I-beam 6.385
Pistons: JE forged 12cc dome
Rings: JE moly 1/16, 1/16, 3/16 standard tension
Bearings: Clevite H-series
Balance: Internal
Cost: $7,495.00
Warranty: Two-year limited
Rabid Rat
The 509 inches of a Rat motor are hard to ignore. The big-block slipped between the framerails of SuperNova without any fanfare, thanks in part to the fact that Novas could be purchased in '69 and '70 with factory-installed 396-inch big-block power, so repro parts are available for the swap. The only major changes needed were the frame mounts and motor mounts, which we procured from Chevy 2 Only, and headers. One should also consider a cowl hood when running a big-block in a Nova, as the hood-to-carburetor clearance is minimal with a tall single-plane intake. The factory used a low-profile dual-plane in stock applications. As such, we were unable to run an air-cleaner assembly. Our 509 featured iron heads and an iron water pump, bringing the fat Rat up to a portly 640 pounds--a hair more than 200 pounds over the mighty Mouse.
 An off-the-line stumble was...  An off-the-line stumble was cured by setting the float levels higher on both the primary and secondary sides of the carburetor. Our e.t.'s showed a 0.15-second improvement as a result. |  By removing the hood, the...  By removing the hood, the big Rat was allotted the air that it so needed to breathe. Here, Matt is placing an air cleaner on the carb to not only protect the engine from the elements, but to also prevent wind buffeting over the carburetor and to direct air into the carb. This action alone dropped our e.t.'s from the mid-12s to the high-11-second range. One should never underestimate a Rat's lung capacity. |  We got the correct frame mounts...  We got the correct frame mounts for a big-block Nova from Chevy 2 Only. We used the '69-'70 style, which are the same as a '69 Camaro's, and set the engine lower than the small-block. |