See all Dart 4.5 Bore Spacing Aluminum Chevy Small Blocks 50mm 350 9.025 4.18 products
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Dart 4.5 Bore Spacing Aluminum Chevy Small Blocks 50mm 350 9.025 4.18
$9528.15
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By spreading the cylinder bore centerlines from the standard 4.400" to 4.500", large bore sizes can be achieved with adequate head gasket sealing space between the cylinders

Bosses are added at the ends of the decks to accommodate two extra head studs, increasing clamping loads and improving gasket sealing. (The extra studs are also provided for in Dart's new 4.500" bore space cylinder heads). These new blocks areIdeal for big inch competition engines. The cam location is raised .391" and oil pan rails are spread .400" per side on both the iron and aluminum blocks, providing lots of room for stroker crankshafts while eliminating the need for fragile small base circle camshafts. Big block cam bearing journals are standard, and 350 or 400 main bearings are available

It is recommended that you contact a Dart technical representative before placing an order for this item. Detailed information about your planned engine build will help to ensure that you choose the right configuration for your motor and that any special parts and considerations are taken into account

Features:

- Premium alloy: Dart aluminum blocks are cast from 355-T61 aerospace alloy for superior strength and durability

- 8.850", 9.025", 9.075", 9.325" and 9.500" deck heights allow for greater versatility

- 4.500" bore spacing comes with 4.180" bore size standard, larger bores available on request, please call

- Ductile iron sleeves and extra thick walls prevent cracking and produce excellent ring seal

- Raised camshaft .391" (4.912" camshaft to crankshaft centerlines) provides more clearance for stroker cranks and eliminates need for fragile small base circle cams. Option for .434 raised cam also available

- Relocated oil pan rails are spread .400" per side (.800" wider than stock) to increase crank/rod clearance and reduce windage losses

- Oil pan bolt holes are relocated in line with main caps to eliminate interference with rotating assembly

- Main bearing bores are available for 350 (2.45") and 400 (2.65") bearings allow engine builders to maximize crankshaft strength and minimize friction

- 4 bolt billet steel main caps have splayed outer bolts minimize bearing bore distortion

- Big block camshaft bearings allow use of cams with larger base circle diameter to improve strength and resist twisting with cam driven pumps

- Dual starter mounts allow starter to be mounted on either side of block for chassis and oil pan clearance

- Front and rear external oil inlets, crossover and restrictor provisions to simplify plumbing with external pump

- Scalloped outer water jacket walls improve coolant flow around the cylinder barrels to equalize temperatures

- Coated cam bearings, freeze plugs and dowels are included

Block Prep Options

Dart blocks are optionally available fully finish prepped. If you choose to order your block this way you can specify a final lifter spec and a final hone spec. Your block will be finish machined to your specs, final prepped and washed, pipe plugs and freeze plugs will be installed, then it will be bagged and boxed. Your block will arrive finished and ready to use!
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Who is Dart?

Dart machinery started in a humble environment. Dart was founded in Oak Park, Michigan, in 1981 in a two-car garage. Dart has developed into an established pioneer in re-market cylinder heads, intake control systems and motor blocks throughout the years after the company started a business using a desk and telephone.

Dart's Commitment to High Quality?

Dart is committed to assembling the best engine components available. All development, machining, and assembly are accomplished at Dart facilities to keep the highest quality measures. CNC, a computerized dynamometer, and the proprietary Maskin are updated to the state of the art technology advancement in the Dart engine production program. Engine program and daily interaction with leading engine builders and winning racers put Dart on the leading edge of technology

The original company products were aluminum Hemi cylinder heads that controlled the top fuel and funny car levels. These purpose-built heads granted the power that ultimately broke drag racing’s 300 mph barrier and designed the first four-second Funny Car elapsed time. In recent years, Dart spread-port Big Chief heads have set the measure in classes ranging from Pro Street to Pro Mod. The launch of the inexpensive Iron Eagle and the PRO 1 cylinder heads for large and small Chevy V8s, backed by aluminum- and cast-iron engine parts, is also continuing this tradition of innovation. Dart considering expanded its product line to include small-block Ford and Honda parts.

Dart at Vivid Racing

Dart was started with a desk, a telephone, and a dream. Dart today is the acknowledged pioneer in race-winning components development. Contact our sales team at (480) 966-3040.

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