Big-Block Shootout: Pt 2

In our quest to provide the best-possible competition for our Big-Block Shootout, we wanted to create an attainable combination our readers could duplicate, yet share something cool, with those same readers, they may not have seen before. In assembling an engine with a professional, we have the benefit of learning from those who build precision competition powerplants every day. When we chose to work with Paul Pfaff Racing Engines of Huntington Beach, California, we had a golden opportunity to learn plenty.

Pfaff's shop has been modifying big-block Chevrolets as long as there has been big-block Chevrolets, mostly for the offshore boat racing crowd. Regular readers have seen us work with Pfaff to create everything from reliable 426hp small-blocks to 1,500hp supercharged 598ci monsters on 92 octane. The specialty of the house has got to be closer to what we're doing here: a stout 454 on pump gas. If it could be tailored to take full advantage of Pfaff's talents, there'd be more cubes, a supercharger, and EFI on board too, but that's a story for another time. Right now, we've got a stout 454 to build, and some seasoned pros to show us how.

The biggest difference between what happens in your garage and what happens inside the assembly room at Pfaff's has to be the tools and the experience. We can't give you a part number for experience, but we can sure show you some of the cool assembly tools professionals use to guarantee your satisfaction. Keep an eye open for them throughout this story, and remember, professionals get paid for a reason. Getting an engine like this assembled is not cheap, but check out the photos to see why. The precision and perfection measured in a top-notch shop is a worthwhile investment for those who need the best there is. We'd like to be able to build engines at this level ourselves, but we simply do not have the equipment the pros have. We felt showing you some high-tech tools and simple tips could both educate you on how it's done right and justify the money professionals charge. When you wonder how such big power numbers can come from relatively small displacements, the assembly is just as critical as the parts themselves.

Remember, this 454 is not built just to keep the Bow Tie pride safe in the presence of the 440 Mopar and 460 Ford, it's also a prize in our latest contest. We'll be giving this engine away (along with the 440 Mopar and 460 Ford) once the Shootout is complete. The only way to enter is to send in one of the entry forms located elsewhere in this magazine, so we'd suggest you do so. Three different winners will be enjoying these engines, so your odds are better than any lottery. Go ahead, send in the card!

Here's a trick Pfaff shared with us. This oil pump mount is broken, so it's trash, right? Wrong; it's now a tool. Pfaff discovered the oil pump changed the dimensions on the main bearing when torqued in place, so by installing this oil pump base and tightening the fastener to spec, the assembler is able to get a more accurate measurement.	Once our crank had been balanced (Pfaff balances all reciprocating assemblies in-house), Gordon got it installed. The block had also been fully-prepped, including a complete cleaning and double-checks of all machining and manufacturing tolerances. Screens have also been installed in the valley area to save the bottom end, should the engine ever encounter valvetrain issues at speed. This is cheap insurance.	Here's a tool we know you'd like. This device measures the finish on the bores, ensuring equality between cylinders and giving the assembler assurance the crosshatch is proper.
The machinist told us the finish should be between an 8 and a 10 on the scale; all of our cylinders came up on 9.	Time to get our rods dialed in. Like the mains, our rod bearings were measure for clearance with an inside micrometer. Once all were deemed perfect, the pistons were pressed on.	Gordon got the rings prepped while the pistons were getting pressed. The file-to-fit rings were dialed in one-by-one and assigned cylinder position. Measuring ring gap is best accomplished using a tool like this one, which keeps the ring level in the bore.
The final check on the rings happens in the dark. A small light (like this one) is used to check the rings conformity to the cylinder wall with the lights out. If any light finds its way between the ring and the bore, something is amiss and must be addressed. We left the lights on for this photo, but you get the idea.	Everything passed muster, so it's time to get the rings on the pistons. Gordon chooses to use a ring installation tool. We know rings can be installed without one, but why take a chance on distorting the ring? The tool is easy to use and inexpensive.	The pistons find a home with help from this installation sleeve. It's tapered, so the rings can easily find their way into the bore. These sleeves are bore-specific, so you've got to have the right size for the proper fit.
Once a piston is installed, the rod bolts get tightened. This most-critical torque is based on rod stretch, and Pfaff depends on a dedicated micrometer used for nothing but measuring this stretch. This measurement has superceded ft-lb figures in this shop.	Our cam is a Crower piece, and is a hydraulic roller design. It carries PN 01406, and the specs are serious. The intake side gets .636-inch lift with 309-degrees of duration, while the exhaust side will see .658-inch lift and 310 degrees of duration; all with 1.7:1 Crower roller rockers. Lobe separation is 110 degrees, and duration at .050 inch is 253-degrees intake and 260-degrees exhaust. It'll be able to idle just fine at about 850 rpm, which is plenty streetable by our standards.	The cam is connected to the crank by a durable and proven Cloyes double-roller timing chain.
A roller bearing is placed between the block and cam gear to prevent galling, and a lock plate keeps all of the hardware secure.	Degreeing the cam is done with the largest degree wheel we've ever seen, teamed with a precision micrometer on the piston top and lifter. Everything was within specs, and we could begin plotting for the heads.	The cylinder heads are proven World Products aluminum Grumpy Jenkins units. These heads have good intake port design, and only need a little porting help on the exhaust side. Pfaff's shop has seen over 350 sets of World Merlins come through, we're confident they know exactly what it'll take to make these heads flow.
We asked for minimal headwork, not wanting this to become a porting contest. Pfaff agreed, and beyond matching up the intake manifold, their proprietary valve treatment, and some cleanup on the exhaust side, not much was needed anyway.	Our valve job, like all those who pass through Pfaff's shop, was done on a Serdi machine. These tools are well-regarded for their accuracy and consistency, we like that.	We're relying on a proven Edelbrock Victor Jr. 454-R intake manifold to feed our fat rat. Our man Kirk carefully matched the ports with the World heads.
With our heads on board atop the block, we could start getting the valvetrain dialed in. After our Crower hydraulic roller lifters, Trick Flow pushrods, and Crower 1.7:1 roller rockers were mocked up, we learned another cool trick from the pros.	Using a simple marker, Gordon marks the valve tip, installs the rocker, runs the valve through a cycle, then removes the rocker again to check the ink pattern on top of the valve tip.	This gives a clear indication of how the roller tip of the rocker is travelling across the valve, and it should be centered for proper operation and wear. As you can see, ours are right on.
Hydraulic roller lifters are easily adjusted, just like flat-tappet hydraulics. A half-turn of preload should be plenty, and we'll check it again after some dyno time. Nothing to it.	Gordon Jennings attended to all of the details to complete our 454, like the valve covers, Moroso oil pan, and Demon carb. We then added an MSD distributor and plug wires to finish it up. A Summit air cleaner will top the carb.