Weingartner 407ci Small-Block Chevy - Teacher’s Pet
Building a 616hp small-block Chevy was elementary for this schoolteacher
From the September, 2012 issue of Popular Hot Rodding
By Daryl White
Photography by Robert McGaffin
The easiest part of this whole...
The easiest part of this whole build was the carburetor. Holley’s 80803 Ultra HP 750 was so well balanced out of the box that Eric Weingartner didn’t change a thing on it. It had a perfect fuel curve.
For whatever reason, we always like to root for the underdog. When the little guy gets one over on “the man,” we go nuts. Maybe it’s because we always see a little of ourselves in that underdog. He’s out there by himself against all odds, neck and neck with the money-is-no-object big boys, and we love it! That’s why when Eric Weingartner showed up with his small-block Chevy for the 2011 AMSOIL Engine Masters Challenge, everyone, including the other competitors, was rooting for him to do well.
You see, Weingartner isn’t a full-time engine builder with an unlimited budget. He’s a schoolteacher from Oklahoma. He works hard for not a lot of pay. He plays by the rules and is as honest as the day is long. He’s the guy the rest of us envy for having the intestinal fortitude to get out there and put his skills to the test against “the biggies.”
Using a ported Dart intake...
Using a ported Dart intake manifold with a Dominator-style carb flange, an HVH Super Sucker carb spacer blended the transition into the runners. The Ultra HP carb comes with slotted mounting boltholes so it can be bolted onto either a standard 4150 intake or a Dominator intake like this one.
Weingartner has been a pretty hard-core engine guy for a while now and though this wasn’t his first trip to the EMC, it was a chance to show what he’s learned over the years. What he’s learned is that he knows how to make more than 600 of those wild Oklahoma horses run fast without a lot of compression or high octane. Weingartner also knows what parts can be a little more friendly to a workingman’s budget and which ones not to skimp on.
The foundation of this 407-cube build, the engine block, was something he absolutely didn’t want to skimp on. He called World Products and ordered one of their splayed-cap SBC 400 Motown blocks, which is different in one key respect: the old-school factory 400 blocks were built without siamesed cylinder walls. What that means is the cylinders have an open water passage next to one another. Good for light weight and low production cost, but bad for keeping the cylinders stable when making lots of torque. The World block uses siamesed cylinder bores for that extra strength. He had his favorite local machine shop, Dunsworth Machine, bore and torque-plate hone the block. Dunsworth’s specialty is circle track engines, so Weingartner was comfortable with the way they machine blocks for endurance and reliability. When asked what tricks they did on the bores, Weingartner was honest about it: “I said do whatever it takes to get it right. I honestly don’t even know what they do. They build a ton of engines and whatever they do works. I check the taper on the bores, and it’s always perfect.”
With the raised runners on...
With the raised runners on the heads, a bit of epoxy was necessary on the floors of the intake runners to get them to line up right.
Part of that endurance philosophy was seen again when Weingartner picked out a forged steel crank from Scat. The superlight crank still maintained the heavy-duty 400 main journal sizes and standard 2.100-inch rod journals. Keeping that standard rod journal with a 3.75-inch stroke meant that some minor block clearancing would be necessary so the rod bolts didn’t try to cut their way through the oil pan rails. Another part of making the engine live in a grueling environment was the decision to internally balance the crankshaft. Stock Chevy 400 cranks were cast iron and required their own externally balanced flywheels and harmonic dampers. Changing to a forged steel crank adds some density to the shaft but the counterweights still weren’t heavy enough to balance it out on their own, so Dunsworth had to add a few small sticks of extremely dense tungsten to each end of the crank.
Also from the Scat lineup, Weingartner picked up a set of I-beam connecting rods. He felt that at the power level he was at, there was no need for the super high-dollar rods. Those sportsman versions would do quite well, thank you.
Standard 11/32-inch stem Ferrea...
Standard 11/32-inch stem Ferrea valves were used but were extra long to accommodate those raised ports. Pro Stock head porter Darin Morgan gave Weingartner a few tips to get the combustion chamber shape just right.
On the small end of the Scat rods, a set of flat-top CP pistons hung, looking fairly ordinary. But they had some minor trickery that Weingartner had picked up over the years. Formula 1–inspired boxed forgings were used to get the best strength-to-weight ratio. Also, a narrow, short skirt cuts down on friction as the aluminum slugs move up and down the cylinders at an average speed of 50 mph. Dragging heavy rings along cast iron at those speeds creates a ton of heat and friction, so Weingartner fitted the pistons for a thin steel top ring, an equally thin napier-hooked second ring, and a low-tension oil ring. To help those thin rings seal under load, Weingartner sent the pistons to Rebco for lateral gas porting. As he is a teacher, it was second nature for him to do some quick math and figure out that with the 6.125-inch rods and 3.75-inch stroke, he would need to have a 1-inch-tall compression height. That meant there wasn’t a whole lot of meat left in the pistons. CP cut the valve reliefs the absolute maximum for those forgings to handle the monster intake valves and tight lobe separation. Any more, they said, and they would clean break.
Wide runners often end up...
Wide runners often end up cutting into the head boltholes between paired intake runners. The simple solution as seen here is to install a thin brass tube to seal it back up. It has no effect on flow numbers but depending on how it is installed, may require narrow head studs on those holes.
For an added bit of safety on the bottom end, Teflon-coated Mahle/Clevite rod and main bearings were used. “I don’t know that they bring you anymore power, but the last time we fired it up, we didn’t have the distributor down all the way engaged with the oil pump shaft. So, we didn’t have any oil pressure for around 30 seconds, but the coating stayed on there and it didn’t do anything. I think that coating provides some insurance.”
“I used a Jegs standard-volume oil pump, but I ported it. I think that’s why this had such good oil pressure. I like that pump because it has such good pressure at idle.” He says that he ran the clearances at .0022 inch on the mains and .0020 on the rods, which accounted for a large portion of the high oil pressure. Often, people run the clearances really loose, searching for that last horsepower, but in the end it can cost them a crankshaft.
The bottom of the intake runner...
The bottom of the intake runner sits almost an inch above the deck. As good as most 18-degree heads, these runners designed by Weingartner were CNC ported at Reher-Morrison and can be reproduced easily thanks to the modern miracle of computers.
Atop the block’s deck sat Weingartner’s pride and joy—his own design of CNC-ported heads. For several years, he had been porting heads in his garage. With the same desire for learning he inspires in his students, he built his own flow bench to test his port designs. He’d gone through countless small-block heads and determined that he had a port shape in mind that would make the incredible torque and high horsepower required of an EMC engine. A call to Brodix ended up with a pair of bare 23-degree 10X raised-runner castings on their way to his home. If he could only sneak them past his wife. He jokes about it, but is dead serious when he says that he absolutely could not do any of this without her support. “I would like to thank my wife, Carrie, and my son, Bishop. She could have kicked my ass out of this many years ago and my son put some luck on the engine. Without them, I don’t have nothin’.”
With the bare castings now in his hands, Weingartner slowly whittled away at the aluminum, removing only the minimum amount of material that would let the right volume of air through. To science out a port can take weeks, especially when your day job is trying to put science into kids and you only have some nights and weekends to get it done. He got to a good point and decided it was time to get a professional critique. By professional, that meant driving to Reher-Morrison and having Pro Stock head porter Darin Morgan finger bang his ports. Nothing like going straight to the top. Darin gave him a couple pointers but overall it was a big thumbs-up as the little Brodix small-block heads flowed over 350 cfm on the Reher-Morrison flow bench! Right in the middle of big-block territory. Of course, it didn’t hurt that they had giant 2.150-inch intake valves.
Doug Herbert supplied titanium...
Doug Herbert supplied titanium retainers and valvesprings for the project. The rocker arms were an off-the-shelf part from Jesel, though the stands were custom. Their specs are now on file with Jesel should they ever need to make another set. When ordering the rockers, Jesel suggested he switch over to having the ball adjuster in the rocker arm and the cup in the top end of the pushrod, instead of having a traditional pushrod with balls on both ends. This helps in applications with lots of rocker ratio or lift.
Priced less than their H-beam...
Priced less than their H-beam brethren, Scat Pro Comp I-beam rods aren’t just a fancy stock replacement. They are 4340 forged steel and have ARP 7/16-inch bolts. Good enough that they are used regularly in 8,000-rpm engines across the country. Also forged, but from aluminum, the CP pistons use lateral gas ports to help the rings seal quickly and fully. Though the numbers vary, gas porting can easily add 5-20 hp for less than $100.
The exhaust ports on the Brodix...
The exhaust ports on the Brodix 10X heads can use either standard or Stahl pattern headers. Since the exhaust is in the standard location, header fitment in an actual car is no problem.
The headers on this school...
The headers on this school bus yellow engine were Schoenfield 1¾ to 1⅞-inch diameter stepped going into a merge collector. Old-school crankcase-to-header evac system reduces crankcase pressure and increases the power output.
Weingartner designed his ports with the goal to have relatively high average airflow velocity, without any tight pinch points that would choke it. He was able to do this by raising the runners and making them fairly wide, but not too tall. “They’re something like 1.37 inches wide by 1.880 tall.” Almost the exact opposite of a cathedral-port LS head. “I tried doing it tall and thin, like 1.228 wide and carrying it all the way through and like 2.200 high but it always liked it wider and shorter than taller and narrower. Kinda goes against that LS thing.” The only downfall to this design was the requirement to use offset lifters and rocker arms.
One of the things he really liked about the Brodix heads was that they had a big, deep bowl area under the valve. A theory that many head porters share is that the deep bowl lets the cylinder get a first big gulp of air as the valve is opening and velocity is building up in the runner. As the intake valve is just starting to open, there is a critical time when the exhaust valve is still slightly open (overlap is just starting) and the pressure remaining in the combustion chamber can be higher than in the intake runner. What that means is some of that exhaust can go up the intake tract (reversion). Not a good thing as it contaminates the nice, clean air in the intake manifold with nasty exhaust. After a few crankshaft degrees of this, the mass and sound pressure waves of the exhaust begin to pull the intake air back down into the chamber (scavenging). So what do we learn from this session? Class? Class? Anyone? Bueller? We want to hurt low-lift reverse intake flow, and we want higher lift flow to be good. One way to do this, which is what Weingartner did, is to use a 50-degree intake valve job angle. A large throat diameter, 91 percent of the intake valve in this case, also helps out.
On the intake side it becomes...
On the intake side it becomes apparent why Weingartner needed the offset version of Isky’s famous roller lifters. Clearing the extra-wide runners was no easy task. Also, looking at how the “standard” Fel-Pro intake gasket sits on the head, it’s clear how raised the runners are.
On the exhaust side, Weingartner ran a traditional 45-degree valve job. This tends to work well with short-duration cams as they open late in the cycle. Opening late is good for holding the pressure of combustion in as long as possible, but they still need to get the exhaust out as quickly as possible once they do crack open. In other words, high low-lift flow numbers are good for exhaust in this case. It seems anathema (trying to impress the teacher here with big words) to want to open the exhaust valve while the piston is still going down on the combustion stroke. It is important to remember though that if we wait until the piston starts coming up before opening the valve, the piston will have to push all that exhaust out. Pushing means pumping losses. The goal then is to balance how much you are going to gain in reducing pumping losses against how much you are going to lose by opening the exhaust valve while combustion is still pushing the piston down. A tight balancing act.
It is only the intake lifters...
It is only the intake lifters that are offset though; the exhausts are centered.
When deciding how to balance that tightrope, Weingartner called Chris Mays at COMP Cams for input on the bumpstick. “The cam specs were 243/247 [intake/exhaust] on a 104 lobe separation with the TK lobes for high rocker ratios. The lobe itself is tiny, ’cause it’s a 1.85 rocker to get that .650-inch lift [max per EMC rules]. But it’s pretty damn aggressive.” The tight lobe separation was picked to get the most benefit from that overlap scavenging and to be able to place the valve opening and closing points where they would work for the best average torque and horsepower. The downfall of running it tight is that it kills the manifold vacuum signal at low rpm and idle so it is tough to run like that with power brakes or any vacuum-operated accessories in a street car.
Though the engine was destined for his own car (look for an update on quarter-mile performance) this beast first had to go back to school. To the University of Northwestern Ohio (UNOH) that is, where the Engine Masters Challenge was held. A virtually unlimited supply of eager young students was on hand to hook Weingartner’s engine to one of UNOH’s DTS/SuperFlow engine dynos. A fresh tank of VP100 fuel was set up to feed the engine and they threw 12 V to his trusty PerTronix ignition system to bring the engine to life. Poor Weingartner looked as nervous as a young boy sent to the principal’s office, but everything changed when the dyno operator hit the GO button, and she fired up. Weingartner jumped out of his seat and screamed “Hell yeah!” Everyone laughed, but he didn’t care if it made 1 hp or 1,000. He met his goal. The schoolteacher from Oklahoma stood up there with the engine that he built and just smiled as big as the plains when he saw that dyno needle climb to a staggering 616 hp. He’d done it all right. Now he really had something to brag about come “show and tell.”
COMP Cams’ adjustable beltdrive...
COMP Cams’ adjustable beltdrive makes it easy to advance or retard the cam quickly without taking off the front of the engine. No special adapters are necessary to use the beltdrive and by the time you add up the cost of a top quality adjustable chain and a good timing cover, it’s not much different to get the COMP beltdrive. Not to mention never having to take the oil pan off to move or swap the cam …
The World Motown block comes...
The World Motown block comes in different configurations to fit just about any small-block combination up to 454 cubes. It is set up for a driver-side dipstick, which is the most common for oil pans, though it has a boss for a pan with a passenger-side dipstick. Priority main oiling ensures that the bottom end gets lubed before any oil heads up to the top end.
One nice feature on the Motown...
One nice feature on the Motown block is that the main cap comes already clearanced for a dipstick. Too often, when a dipstick is pulled out of an aftermarket block, the main cap rubs off the oil on the tip, making reading the oil level impossible.
|By The Numbers
407ci Small-Block Chevy
||407 actual cubic inches
||COMP Cams solid roller
||243/247 degrees at .050-inch tappet rise
||Jesel 1.85/1.7 ratio
||.043-inch Total Seal
||Scat I-beam 6.125 inches
||Brodix 10X raised runner
|Intake valve diameter:
|Exhaust valve diameter:
||Holley Ultra HP 750