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Mag Build • 363 Warhorse ShortBlock PT.2

3K views 0 replies 1 participant last post by  coasthigh 
#1 ·
The Screaming Eagle, Part 2
WE TOP OFF OUR SHORTBLOCK WITH GOODNESS
FROM EDELBROCK, COMP, SCE AND ARP

Two months ago, you read about our Coast High Performance Pro Street 363-cube shortblock being put together by the good folks over at CHP. This month, we head back over to their assembly room and follow along as they assemble the top half of the engine using some really nice parts from Edelbrock, Comp, SCE and ARP. Our goal with this motor isn't about building a class-killer or a high dollar custom bullet that will make great dyno sheets, and then eat itself at the track. Rather, this motor is being put together with parts commonly available on the shelves of your local speed shop, and will make solid, reliable power with good street manners.

HEADING UP THE LIST

Arguably, the most crucial part in the top end is the cylinder head. For our project, we turned to one of the largest names in aluminum cylinder heads, who also happens to be in our backyard - Edelbrock. When we told them what we were doing, they suggested one of their newest designs for the small-block Ford; the RPM Extreme. Cast and machined entirely in Southern California, the RPM Extreme is known informally as the "RPM XT" or simply the "XT," and features a unique design. By using a combination of as-cast design, and CNC-porting, the XT heads offer the maximum blend of performance and affordability. They feature CNC-porting to crucial areas such as the entry of the intake ports, the exit of the exhaust ports, and the intake and exhaust bowls. The XT's combustion chambers are fully CNC'd and measure out to 59cc. The CNC-profiled intake ports feature a volume of 185cc and the flow sheet shows 292 cfm of flow at .600-inch lift. The exhaust ports, which are CNC profiled similarly to the intake ports, measure out at 75cc and flow 209 cfm at .600- inch of valve lift.

The RPM Extreme comes assembled with stainless steel valves that measure out to 2.02-inch intake and 1.57-inch exhaust - with 8mm stems, which have a traditional 18-degree angle. Conical valve springs are utilized for valve-train stability and will handle up to a .600-inch lift camshaft profile. The heads also come with 7/16-inch rocker studs, and hardened steel guide plates. The heads have been designed with a 5/8-inch deck thickness and 1/2-inch head bolt bosses. Normally, that would require the use of a head stud bushing with the stock 7/16-inch head bolt holes, but since our Dart block has 1/2-inch head stud holes, it all works together without the use of any bushings.

MANNING THE GATES

A great flowing head is nothing if the supporting gear isn't there to properly open and close the valves, and for those components we looked no further than the supplier of our camshaft - Comp Cams. Their Ultra-Gold Series of studmount rocker arms are designed specifically for high performance street and race engines. Precision machined out of aluminum, the Ultra-Gold arms feature modern design features that reduce their weight and increase their ratio accuracy. Even with their lighter weight, their strength has been maintained and they are able to withstand extremely aggressive spring pressure and valve lift, and the rockers have a lifetime warranty from Comp. For lifters, we went with Comp's OE-style High Energy hydraulic roller lifters. Designed to be a direct replacement for the stock lifters, the lifters work well with either a stock cam or, as in our case, one of Comp's hi-po hydraulic roller camshafts. We also sourced a set of Comp's Hi Tech pushrods to sit atop the lifters and actuate the rockers. They are a one-piece design made from .080-inch wall seamless chromoly tubing for maximum strength and durability. The design uses precision-formed and reinforced 5/16-inch ball ends, which are then heat-treated. To finish them off, the pushrods are black-oxide finished and laser etched with part numbers and lengths.

CONTAINING THE POWER

When it comes to head gaskets and street cars, copper gaskets really don't pop up on the radar. However, after talking to Ryan Hunter at SCE Gaskets about the project, they convinced us that their Titan ICS gasket would hold anything we could throw at it as far as cylinder pressure, and that the gasket's unique built-in coolant seals not only wouldn't require any additional sealants, but would work for our application. The sealing of the water passages is achieved by patented bead seals which are bonded directly onto the gasket surface itself, forming a waterproof seal between the both the head and gasket, and the block and gasket. With our coolant concerns assuaged, we took a more in-depth look at what makes the Titan ICS so strong. The Internal Combustion Seal (ICS) actually takes the place of the O-ringing of the head and block, and consists of a stainless steel O-ring that is inserted into the body of the gasket. It seals by he same theory as a normal O-ring, but without the need to machine the head and block to accept the wire. Additionally, should cylinder pressures get high enough to cause a head to lift; the upper and lower seal flanges act as a secondary barrier that expands as the head lifts. However, we don't expect that to ever be an issue with this motor, but it's nice to know that the gasket will handle whatever we throw at it down the line.

The next part of the sealing puzzle is clamping the head onto the block, and to help us with that, we turned to our friends at Automotive Racing Products. When it comes to engine fasteners, ARP is the industry leader in fastener technology. While there is a debate between head bolts and studs in a street car, since we were assembling the motor on an engine stand, and don't plan on ever taking the heads off while the motor is in the engine bay, it made the choice to go with studs and easy one. Starting with an 8740 alloy, each ARP head stud is precisely heat treated. They are then put through a centerless grinding process to make them as concentric as possible before cutting the threads. By cutting the threads after heat treating, the fatigue strength is increased ten-fold over fasteners with threads cut prior to heat treating. We also opted for the undercut studs. This is a procedure, done only to the shorter of the head studs which equalizes the "stretch" of both the long and short fasteners, providing a more consistent clamp load across the deck surface.

FEEDING THE BEAST

To top off our combo, we again looked in the Edelbrock catalogue to see what would match what the guys who know what they are talking about say our powerband will be, and sure enough, the Edelbrock Performer RPM II fit the bill perfectly with an advertised powerband of 1500-6500 rpm. Edelbrock says that it's ideally suited for a street/strip car, which is good, since the car will be driving to and from the track, but we also know they are capable performers at the track, as we've seen them under the hood of several Renegade cars. Granted, those particular pieces have been worked over with a die grinder as much as the rules will allow, but still, it speaks to the design. The inlet on the Performer RPM II is sized to exactly mate up to a 70mm throttle body, and since we aren't currently planning on porting the manifold at all, we opted for an Edelbrock 70mm throttle body with matching EGR spacer. Since we don't need to wring every last ounce of power from this motor to achieve our ET goals, we think that the 70mm opening when combined with a blower will be more than capable. With the engine now good to go, it's just a matter putting the new Tremec TKO 600 under the car and then we're ready to drop in our new bullet, Stay tuned…

SOURCES

Coast High Performance
866-249-9143
www.coasthigh.com

ARP

Comp Cams
1-800-999-0853

Edelbrock
310-781-2222

SCE Gaskets
661-728-9200
 
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