Slow,
I am running a .060" 400 based on a 1970 400 4-Bolt Main Block. It was align honed and both the block surfaces and caps were cut to maintain the correct crankshaft to deck centerline.
The oil passages were drilled out with special extra-long bits and everything was polished to a mirror finish. The oil pump was blended to match the new, larger oil pump feed hole in the block.
The front oil galleys were tapered, tapped and plugged with narrow 3/8" 'flush-fit' plugs with a pointed back profile pirated from a 429 Ford.
The stock 'N' crankshaft was cut .010" and micropolished. Stcok rods were polished and resized with new bolts. All rods were lightened to the weight of the lightest rod. Balancer is a Professional Products unit.
The pistons are Speed-Pro Coated Skirt Hypereutectics (L2262F) and the block was squared and decked. Pistons are .005" 'out-of-the-hole' at TDC. Speed Pro Moly Rings were used. The deck is drilled for the '421 style' colling modification.
The 6X-4 heads were also drilled for the '421' cooling modification and ported, polished and gasket matched. Guides are 'K-Line Bronze' inserts with S-I OEM Valves 2.11" intake and 1.66" exhaust.
New (OEM) dual springs were used with ARP Studs, Crane Poly Locks and Comp Cams 1.5 Roller Tip Rocker Arms.
Airflow was 220 cfm intake and 195 cfm exhaust @ .600" lift and 28 in/H20.
The camshaft is of my own design and lift was based on the airflow of the ported and polished 6X-4 heads. Lift is .461"/.461" with 220°/226° @ .050" on a 111.5° LSA. This is a flat-tappet hydraulic.
Intake is an Edelbrock Performer with exhaust crossovers welded shut and 1/4" pass holes drilled, similar to those found on the popular Edelbrock Heads.
Carburetion is a List #80783 Holley 650 Vacuum Secondary and a stock HEI was recurved to provide 16° initial, 20° mechanical by 2800 rpm and 10° of ported vacuum advance.
The engine will be fitted with Hedman #28150 1-3/4 primary Headers and a Flowmaster #17103 Crossflow 2.50" Mandrel Bent System with the #42585 Crossflow Muffler. This complete system is already in the car and running.
Flywheel is a new hays 30 pound steel unit contained in the stock Pontiac Aluminum Bell Housing. Clutch is an 11" Diaphraghm unit.
Gearbox is a 1968 M-22 'Dual Drain Plug' 1" Countershaft Case fitted with a new M-20 gearset with 2.52:1 first gear ratio. Tailshaft is the small 28 spline unit with a 'passenger's side speedo' tailhousing.
Shifter is a new Hurst Competition Plus and linkage is the giant 1/2" rods from an early Corvette.
The Differential is a 1979 8.50" 10 Bolt with disc brakes and 3.23:1 gearset. Brand new Superior stock replacement axles were used. The entire brake system is new and D.O.T 5 Silicon Fluid is used, as it has been since 1986 in all my cars.
Wheels awaiting installation are 15 X 8 X 4.5" Corvette Rallye's powder coated silver, mounted NASCAR style withou trim rings or center caps.
Since the build is in-progress, I cannot tell you what kind of performance the car will have. However, I can tell you that even with the stock 42,000 mile 350, it is a blast to drive.
I hope this information is helpful...Robert
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