Dart Vader
08-04-2008, 07:51 PM
Check out a full Q&A article on the SHP Block, Dart's latest and greatest performance engine block along with new short block assemblies and top end kits. This new block revolutionizes the standard for top quality and performance out of an engine block. Read the full Q&A below.
Special High Performance Q&A
Straight Talk from Dick Arons About Dart's New SHP Block and Engine Kits
Dick Arons is well known to racing fans as one of the founding fathers of Detroit's infamous "Rat Pack" – a group of diehard racers who cut a wide swath through drag racing's doorslammer classes in the '60s and '70s. Arons teamed up with Wally Booth to build some of the quickest Super Stock and Modified Production Chevys in Motown for a roster of winning racers that included NHRA World Champion Mike Fons, Paul Mercure, and a young Richard Maskin.
Booth and Arons jumped into Pro Stock with a killer Camaro in 1970, but it was their Pro Stock AMC Hornets that soon revolutionized the category. Racing in tandem with the Maskin & Kanners AMC team, the "Ramblers" dominated Pro Stock in 1976, winning four of the eight NHRA national events on the schedule.
With AMC facing hard financial times and ending its factory racing program, Booth and Arons retired from national competition to focus on their engine building business. Thirty years later, Arons reunited with Maskin when he joined Dart Machinery to head up the Special High Performance Group – an alliance that soon produced the new Dart SHP block and SHP engine kits. In the following Q&A, Arons talks about the design and development of these new products.
Q: The small-block V-8 has been around for 55 years. Why did Dart decide to produce a new Special High Performance block?
Arons: Although GM has produced millions of small-blocks, finding a good used block today is very difficult – and it's virtually impossible if you are looking for a big-bore 400ci block. Even if you can find a usable core, the economics of rebuilding and blueprinting a junkyard block don’t make sense. By the time a customer buys a used block and has it cleaned, pressure checked, decked, bored, and honed with a torque plate, the cost is higher than a brand-new SHP block that's already machined to precise tolerances. Just finish hone the cylinders in an SHP block and it's ready to assemble. In addition, the SHP block is stronger than a production block and has performance features that simply aren't available in a stock casting.
Q: What are the recommended applications for the SHP block?
Arons: The SHP block is an excellent choice for anyone who wants to build an affordable high-performance small-block V-8. When we designed the SHP block, we targeted hot rodders, bracket racers, restricted circle track classes, off-roaders, and high-performance boats. The SHP block will easily support 600 horsepower. The SHP block costs hundreds of dollars less than a Bow Tie block, so it's a terrific value.
Q: How did you reduce the cost of the SHP block without compromising its quality?
Arons: We started with a clean sheet of paper when we designed the SHP block tooling. Even though it looks like a conventional first-generation small-block on the outside, we rethought the entire manufacturing process. Dart has learned a great deal about how to produce cylinder heads and blocks efficiently, and all of that experience went into the SHP block. For example, the factory small-block oiling system has numerous intersecting passages with sharp angles that reduce flow. We simplified the system so there are fewer holes to drill and less restriction to the oil flow – so Dart's design costs less to manufacture and actually improves reliability.
Q: Where is the SHP block made?
Arons: The SHP block is made in the USA. While some of our competitors are going to low-cost imports from China and India, Dart is committed to maintaining high quality. Our blocks are cast in American foundries where we can constantly monitor the quality of the material and workmanship. If there is a problem, we fix it today, not three or four months later. Except for the actual pouring of the iron, every step of production is done in-house at Dart's manufacturing facilities in Michigan. We use the same Makino CNC machining centers to produce SHP blocks that we use to make our top-of-the-line Race Series blocks.
Q: What bore sizes and main bearing diameters are available in SHP blocks?
Arons: We offer one casting with a choice of 4.00" or 4.125" cylinder bores. Every SHP block has 2.45" (350-type) main bearings. By producing only two part numbers that cover 95 percent of the high-performance small-block market, we are able to keep the price affordable. The cylinder walls in SHP blocks are siamesed, and the minimum wall thickness is .230" at a 4.165" bore diameter. We've learned in Pro Stock that a big cylinder bore really improves breathing by unshrouding the valves.
Q: What are some of the improvements in the SHP block over a production casting?
Arons: The SHP block has a true priority main oiling system. In a production small-block the main oil gallery is above the camshaft, but we relocated it to the side of the camshaft tunnel. In the SHP block, pressurized oil is sent directly from the oil gallery to the main bearings instead of being routed around the cam bearings like a production block.
The SHP block has scalloped outer water jacket walls so there is excellent coolant flow around the cylinder barrels. The bottom end has clearance for a 3 3/4" stroke crankshaft with steel rods so you don't have to grind the oil pan rail and the bottom of the cylinder bores. The deck surface is 5/8" thick and the head bolt holes are blind-tapped into reinforced bosses. This stiffens the deck surface, increases the clamping load on the head gasket, and eliminates coolant seepage around the head bolts – you don't need sealer on the bolt threads, just lubricant.
The SHP block's three middle main bearing caps have four bolts, and the outer bolts are splayed to anchor the caps securely to the strongest part of the block. The outer bolts are 3/8" so the bolt heads will clear an inexpensive stamped steel oil pan. The SHP main caps are ductile iron, which is the same high-quality material we use on our Little M sportsman blocks. So with all of these improvements, the SHP block is superior to any production block.
Q: Does the SHP block accept stock parts?
Arons: We made a real effort to make the SHP block as user-friendly as possible. There's nothing more frustrating than installing a new engine and finding out that you can't attach a bracket or the clutch linkage. The SHP block has front and side engine mounts, two mounting bosses for clutch pivot balls (standard and Corvette locations), a mechanical fuel pump mount, starter mounting holes for small and large flywheels, and a full-size spin-on oil filter. There are pads at the back of the block that can be drilled and tapped for detonation sensors.
We designed the SHP block to use inexpensive, readily available parts. For example, the block is machined for OEM hydraulic roller lifters. The OEM-type lifters are much less expensive than aftermarket conversion hydraulic roller lifters, and they work great with a high-performance camshaft profile. The front of the SHP block is machined for a stock OE camshaft thrust plate, and it accepts either a stamped steel or plastic timing chain cover. The passenger-side oil pan rail has a dipstick mounting boss, and you can use any 1981-85 oil pan.
We decided to use a rear main bearing cap designed for a two-piece crankshaft seal for several reasons. Hot rodders and racers have always preferred the early-style cranks because they don't require a counterweighted flywheel like a crank that's made for a one-piece seal. The flywheel bolt circle is larger on an early-style crank as well. All of the aftermarket crankshaft manufacturers offer cranks designed for two-piece rear seals in a variety of stroke lengths. You can get a crankshaft for an SHP block almost anywhere, and use an off-the-shelf flywheel and balancer.
Q: What are the SHP short-block kits and assemblies?
Arons: We think the SHP engine assemblies are a great alternative to crate motors because they keep speed shops and engine builders in the business. Dart supplies the basic components – the block, crankshaft, pistons, rods, and rings. We buy the parts in quantity so the price is very reasonable, and all of the components are designed to work together so there aren't any surprises. A shop can finish the engine with a Dart top-end kit that includes the cylinder heads, intake manifold, valve covers, and even the spark plugs. The engine builder or customer supplies the camshaft and valvetrain that's best suited to the application.
These engine kits make big horsepower. Our prototype 400-cubic-inch SHP engine with 10.5:1 compression, a hydraulic roller cam, Dart 200cc cylinder heads, and a Dart single-plane intake manifold made 525 horsepower at 6000 rpm and 525 lb.-ft. torque at 4000 rpm. That's more power from a simple first-generation small-block than you get from an LS7 crate motor that costs $13,000 – and that's without a computer and wiring harness to run it!
We also tested a 372-cubic-inch SHP motor with 9.5:1 compression ratio and 180cc heads with a Dart dual-plane intake manifold – a very streetable package. It made 470 horsepower at 5800 rpm and 470 lb.-ft. torque at 4200 rpm. This is a great combination because it takes advantage of the improved breathing you get with a 4.125" cylinder bore combined with a relatively inexpensive 350 crankshaft.
Q: So to sum up, why should an enthusiast consider a Dart SHP block?
Arons: Although there is a lot of media coverage about LS engines and Hondas, in reality it's still a small-block world. If you go to any bracket race, oval track event, or cruise night, the vast majority of cars are powered by first-generation small-block V-8s. The SHP block gives anyone working on a budget a brand-new, high-value block with features that aren't available in any production engine. When you look at the real cost of rebuilding a junkyard block or buying a crate motor, there is no question that you get better quality and more bang for the buck with a Special High Performance block or SHP engine assembly from Dart.
Special High Performance Q&A
Straight Talk from Dick Arons About Dart's New SHP Block and Engine Kits
Dick Arons is well known to racing fans as one of the founding fathers of Detroit's infamous "Rat Pack" – a group of diehard racers who cut a wide swath through drag racing's doorslammer classes in the '60s and '70s. Arons teamed up with Wally Booth to build some of the quickest Super Stock and Modified Production Chevys in Motown for a roster of winning racers that included NHRA World Champion Mike Fons, Paul Mercure, and a young Richard Maskin.
Booth and Arons jumped into Pro Stock with a killer Camaro in 1970, but it was their Pro Stock AMC Hornets that soon revolutionized the category. Racing in tandem with the Maskin & Kanners AMC team, the "Ramblers" dominated Pro Stock in 1976, winning four of the eight NHRA national events on the schedule.
With AMC facing hard financial times and ending its factory racing program, Booth and Arons retired from national competition to focus on their engine building business. Thirty years later, Arons reunited with Maskin when he joined Dart Machinery to head up the Special High Performance Group – an alliance that soon produced the new Dart SHP block and SHP engine kits. In the following Q&A, Arons talks about the design and development of these new products.
Q: The small-block V-8 has been around for 55 years. Why did Dart decide to produce a new Special High Performance block?
Arons: Although GM has produced millions of small-blocks, finding a good used block today is very difficult – and it's virtually impossible if you are looking for a big-bore 400ci block. Even if you can find a usable core, the economics of rebuilding and blueprinting a junkyard block don’t make sense. By the time a customer buys a used block and has it cleaned, pressure checked, decked, bored, and honed with a torque plate, the cost is higher than a brand-new SHP block that's already machined to precise tolerances. Just finish hone the cylinders in an SHP block and it's ready to assemble. In addition, the SHP block is stronger than a production block and has performance features that simply aren't available in a stock casting.
Q: What are the recommended applications for the SHP block?
Arons: The SHP block is an excellent choice for anyone who wants to build an affordable high-performance small-block V-8. When we designed the SHP block, we targeted hot rodders, bracket racers, restricted circle track classes, off-roaders, and high-performance boats. The SHP block will easily support 600 horsepower. The SHP block costs hundreds of dollars less than a Bow Tie block, so it's a terrific value.
Q: How did you reduce the cost of the SHP block without compromising its quality?
Arons: We started with a clean sheet of paper when we designed the SHP block tooling. Even though it looks like a conventional first-generation small-block on the outside, we rethought the entire manufacturing process. Dart has learned a great deal about how to produce cylinder heads and blocks efficiently, and all of that experience went into the SHP block. For example, the factory small-block oiling system has numerous intersecting passages with sharp angles that reduce flow. We simplified the system so there are fewer holes to drill and less restriction to the oil flow – so Dart's design costs less to manufacture and actually improves reliability.
Q: Where is the SHP block made?
Arons: The SHP block is made in the USA. While some of our competitors are going to low-cost imports from China and India, Dart is committed to maintaining high quality. Our blocks are cast in American foundries where we can constantly monitor the quality of the material and workmanship. If there is a problem, we fix it today, not three or four months later. Except for the actual pouring of the iron, every step of production is done in-house at Dart's manufacturing facilities in Michigan. We use the same Makino CNC machining centers to produce SHP blocks that we use to make our top-of-the-line Race Series blocks.
Q: What bore sizes and main bearing diameters are available in SHP blocks?
Arons: We offer one casting with a choice of 4.00" or 4.125" cylinder bores. Every SHP block has 2.45" (350-type) main bearings. By producing only two part numbers that cover 95 percent of the high-performance small-block market, we are able to keep the price affordable. The cylinder walls in SHP blocks are siamesed, and the minimum wall thickness is .230" at a 4.165" bore diameter. We've learned in Pro Stock that a big cylinder bore really improves breathing by unshrouding the valves.
Q: What are some of the improvements in the SHP block over a production casting?
Arons: The SHP block has a true priority main oiling system. In a production small-block the main oil gallery is above the camshaft, but we relocated it to the side of the camshaft tunnel. In the SHP block, pressurized oil is sent directly from the oil gallery to the main bearings instead of being routed around the cam bearings like a production block.
The SHP block has scalloped outer water jacket walls so there is excellent coolant flow around the cylinder barrels. The bottom end has clearance for a 3 3/4" stroke crankshaft with steel rods so you don't have to grind the oil pan rail and the bottom of the cylinder bores. The deck surface is 5/8" thick and the head bolt holes are blind-tapped into reinforced bosses. This stiffens the deck surface, increases the clamping load on the head gasket, and eliminates coolant seepage around the head bolts – you don't need sealer on the bolt threads, just lubricant.
The SHP block's three middle main bearing caps have four bolts, and the outer bolts are splayed to anchor the caps securely to the strongest part of the block. The outer bolts are 3/8" so the bolt heads will clear an inexpensive stamped steel oil pan. The SHP main caps are ductile iron, which is the same high-quality material we use on our Little M sportsman blocks. So with all of these improvements, the SHP block is superior to any production block.
Q: Does the SHP block accept stock parts?
Arons: We made a real effort to make the SHP block as user-friendly as possible. There's nothing more frustrating than installing a new engine and finding out that you can't attach a bracket or the clutch linkage. The SHP block has front and side engine mounts, two mounting bosses for clutch pivot balls (standard and Corvette locations), a mechanical fuel pump mount, starter mounting holes for small and large flywheels, and a full-size spin-on oil filter. There are pads at the back of the block that can be drilled and tapped for detonation sensors.
We designed the SHP block to use inexpensive, readily available parts. For example, the block is machined for OEM hydraulic roller lifters. The OEM-type lifters are much less expensive than aftermarket conversion hydraulic roller lifters, and they work great with a high-performance camshaft profile. The front of the SHP block is machined for a stock OE camshaft thrust plate, and it accepts either a stamped steel or plastic timing chain cover. The passenger-side oil pan rail has a dipstick mounting boss, and you can use any 1981-85 oil pan.
We decided to use a rear main bearing cap designed for a two-piece crankshaft seal for several reasons. Hot rodders and racers have always preferred the early-style cranks because they don't require a counterweighted flywheel like a crank that's made for a one-piece seal. The flywheel bolt circle is larger on an early-style crank as well. All of the aftermarket crankshaft manufacturers offer cranks designed for two-piece rear seals in a variety of stroke lengths. You can get a crankshaft for an SHP block almost anywhere, and use an off-the-shelf flywheel and balancer.
Q: What are the SHP short-block kits and assemblies?
Arons: We think the SHP engine assemblies are a great alternative to crate motors because they keep speed shops and engine builders in the business. Dart supplies the basic components – the block, crankshaft, pistons, rods, and rings. We buy the parts in quantity so the price is very reasonable, and all of the components are designed to work together so there aren't any surprises. A shop can finish the engine with a Dart top-end kit that includes the cylinder heads, intake manifold, valve covers, and even the spark plugs. The engine builder or customer supplies the camshaft and valvetrain that's best suited to the application.
These engine kits make big horsepower. Our prototype 400-cubic-inch SHP engine with 10.5:1 compression, a hydraulic roller cam, Dart 200cc cylinder heads, and a Dart single-plane intake manifold made 525 horsepower at 6000 rpm and 525 lb.-ft. torque at 4000 rpm. That's more power from a simple first-generation small-block than you get from an LS7 crate motor that costs $13,000 – and that's without a computer and wiring harness to run it!
We also tested a 372-cubic-inch SHP motor with 9.5:1 compression ratio and 180cc heads with a Dart dual-plane intake manifold – a very streetable package. It made 470 horsepower at 5800 rpm and 470 lb.-ft. torque at 4200 rpm. This is a great combination because it takes advantage of the improved breathing you get with a 4.125" cylinder bore combined with a relatively inexpensive 350 crankshaft.
Q: So to sum up, why should an enthusiast consider a Dart SHP block?
Arons: Although there is a lot of media coverage about LS engines and Hondas, in reality it's still a small-block world. If you go to any bracket race, oval track event, or cruise night, the vast majority of cars are powered by first-generation small-block V-8s. The SHP block gives anyone working on a budget a brand-new, high-value block with features that aren't available in any production engine. When you look at the real cost of rebuilding a junkyard block or buying a crate motor, there is no question that you get better quality and more bang for the buck with a Special High Performance block or SHP engine assembly from Dart.