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Dart SHP Sport-Block Engine Build
We Combine A Dart SHP Short-Block And Top-End Kit To Produce 476 Hp Without Breaking The Bank.
We ordered one of the cheaper versions of the SHP short-block. It still came with the Sportsman block, but we opted for the cast-steel crankshaft rather than the forged one. We also selected I-beam rods instead of the pricier H-beam pieces, but the pistons are the same forged slugs as in all of the SHP short-blocks. One option we chose was the larger 4.125-inch bore (rather than the 4.030-inch standard). The larger bore increases the cubic inches from 347 to 363. For those keeping track, Dart builds all of its 302-based engines with 3.400-inch crankshafts.
According to Dart's website, the short-block retails for a mere $3,939 with the optional 4.125-inch bore. A fully optioned short-block comes to the party at $4,814 (363ci, forged crank, H-beam rods). The base 347ci short-block is available from Dart's website for just $3,475. Other components include coated Clevite bearings, coated cam bearings, and Hastings moly rings. Dart includes forged flat-top pistons, and when combined with a 62cc chamber and proper thickness head gasket, the compression ratio is 9.7:1. Our engine could be run on 91-octane fuel, making it compatible on pump gas in California and some states in the middle of the country. Dart offers in-house coatings on pistons and any other engine part for an additional cost.
The thing we like about the Dart product offerings is that the short-block is shipped in a box, ready for a top-end and oil pan. The top-end kit comes in similar fashion--one big box that includes all the parts and pieces.
Our goal with this engine build was to assemble an above average combination without breaking the bank. With that goal in mind, we selected a Ford Pro1 top-end kit, with larger 195cc aluminum cylinder heads and a single-plane Professional Products intake manifold. At our request, Dart ordered a hydraulic roller camshaft (from Comp Cams). The stick is mild and perfect for the street/strip crowd. The top-end kit comes with assembled cylinder heads, intake, cast-aluminum valve covers (ours had optional sheetmetal), intake gaskets, head gaskets, exhaust gaskets, NGK spark plugs, and head bolts. Valvetrain components are available from Dart, but they aren't included in the top-end package.
Earlier we mentioned Dart's experience in NHRA Pro Stock and how it lends a hand in the R&D of Dart's mainstream products. The Pro1 cylinder heads benefit from wet-flow technology. As we all know, the flowbench is the cylinder-head porter's best test tool, much like an engine dyno is the ultimate tool for developing a complete engine package.
Dart has taken flowbench testing to the next level with its custom wet-flow bench. The wet-flow technology was derived as a result of Maskin looking to gain an edge in Pro Stock. The basic concept is, why flow only air through a cylinder head's port when in the real world there is air and fuel moving through it? The answer is a flowbench that moves air and liquid to simulate fuel through the cylinder head ports to test the results in a real-world scenario. The Pro1 was developed with this technology at the fingertips of the R&D team.
The 195cc Pro1 heads are made of 355-T6 aluminum and have all the features that most enthusiasts are looking for in a head. The intake port flows 285 cfm at 0.600-inch lift using 28 inches of water. On the exhaust side, the port moves 185 cfm at both 0.600-inch and 0.700-inch lift measurements. The intake port increases flow to 288 cfm at 0.700-inch lift. The combustion chamber measures 62 cc, which is pretty standard in most aftermarket small-block Ford cylinder heads. The intake valves measure 2.02 inches, while the exhaust is released through 1.60-inch valves. The Dart team selected a Comp hydraulic roller camshaft (PN XE282HR-12) for this engine, and it enters our realm boasting 0.565/0.574-inch lift and duration readings of 232/240 at 0.050-inch, intake and exhaust, respectively. Lobe separation is 112 degrees, giving this engine a nice rumble at idle.