If you've been following our little engine shootout series, then you're already familiar with our self-imposed guidelines for the building of the three Battle of the Titans engines. As a refresher, the small-blocks must not exceed 365 ci, and they must run on pump gas, be equipped with a hydraulic flat-tappet cam, and use production iron cylinder heads. Those heads can't be messed with, and the whole deal has to be topped with a dual-plane intake. Oh, and then there's the budget--$2,500, including machine work, though the cost of the core parts (block, crank, and so on) doesn't have to be included on the balance sheet. The carb, ignition, and headers are considered ancillary items that will be supplied for the test so they are not included in the price. The carb is a Demon 750-cfm unit, which will be shared by all the engines, and the headers were agreed to be full-length 15/8-inch tubes, this time from Hooker.
The stories on the Mopar 360 and Ford 351W have already run in these pages in the preceding issues, leaving the Mouse motor as the final buildup before we get to our dyno shootout next month. Onlookers who can remain at least somewhat impartial will no doubt assume that the Chevy has the advantage, since the most stifling element of the rules is certainly the bit about unported factory castings.
Unless you've been under a rock for the past few years, you know of GM's Vortec heads, designed for use on light trucks and put into production with the '96 model year. The factory was looking for increased efficiency, but of course, where there's efficiency, there's usually more power. The aftermarket caught on pretty quickly and Edelbrock took care of the one major hurdle to mounting these heads on your typical carbureted small-block by building a series of intake manifolds specifically for the unique Vortec intake manifold mounting arrangement.
What many people don't realize is that Ford also has it's own version of the small-block high-velocity/fast-burn-style head, dubbed the GT-40P. It too was designed for light trucks, specifically, the V-8-powered Explorers from the '97 until the end of the 5.0 pushrod V-8. That leaves the Chrysler, but don't sell the Mopar short. With factory-engineered 18-degree valve angles and relatively big valves (2.02/1.60) combined with the longest stroke of the shootout (3.58 inches) and the longest connecting rod (6.123 inches), it isn't exactly handicapped.
But those are bench-racing topics ripe for excuses after dyno day is done and after the dust has settled to the dyno-cell floor. For that, you'll have to tune in again next month, though we'll mention that two of the three engines have already run, and the results were not as predicted. The Chevy can still clean house--or fail miserably. We figured out our combination and took the accumulated parts and pieces to JMS Racing Engines in Monrovia, California, the same facility that machined the Ford and the Mopar and dyno'd all three engines.
JMS has been around for nearly 30 years and has spent a good portion of that time building engines for various forms of competition, from the drags, to circle tracks, to the Salt Flats, and even the water. The experienced staff (many of whom are racers themselves) was invaluable in ensuring that our cobblings on paper could actually be turned into reality without creating expensive shrapnel. Check out the details of the buildup and stick with us next month when we put all three engines to the crucible test of the engine dyno.
Rather than starting with a bare block and scrounging all the other components, we went to the boneyard and scored a complete engine. We like to pull motors that look as if they've never really been messed with to improve the chances that the insides are virgin and intact. This 350 came from a '77 Malibu wagon and its appearance proved legit--the standard-bore block was so nice it could have been rebuilt with standard slugs, but we opted to go 0.030-inch over.
Obviously, when you're building on a budget, you need parts at the best possible prices. We discovered that Northern Auto Parts in Sioux City, Iowa, offers engine kits at extremely reasonable prices, and its Chevy 350 kit in particular seemed like the ultimate bargain at $155. That price gets you a set of cast Federal-Mogul pistons; Hastings rings; Federal-Mogul rod, main, and cam bearings; a stock Melling timing set; a Melling oil pump; a Victor-Reinz gasket set; a stock Federal-Mogul cam and lifter set; and a set of frost plugs. The cool part is that the customer can upgrade individual items to his own liking, with the price adjusted accordingly. We opted for better Speed-Pro hypereutectic flat-top pistons, Hasting performance moly rings, a Cloyes double-roller adjustable timing set, and a Crane cam kit, and the kit was still only $411--an absolute steal.
We disassembled the engine ourselves, cleaned off the heavy gunk, and delivered the bare block with the crank still in place to JMS. Since it was relatively clean and free of rust, Jeff Johnson and Will Didier were able to run it through the clean-up department with only a quick pass through the hot tank.
Block-guy Sal Alcarez inspected the cleaned block and performed the Magnafluxing process to ensure there were no cracks before mounting it in the boring bar. The bores were taken out 0.030 inch, leaving room for future freshening. We briefly considered going to 0.060 inch for a couple extra cubes, a shade more compression, and slightly increased unshrouding of the valves, but we decided the gains would be minimal at this power level.
Next, Sal ran the block through the hone. The Speed Pro pistons were measured prior to firing up the rig to determine exactly where the bore diameter should be when finished. According to the enclosed instructions, the anti-scuff coatings on the skirts of our Speed Pros must actually be taken into consideration when measuring the pistons, since the coating itself will make the pistons seem extra large for the intended bores. However, those measurements can be misleading, since the coating is not actually part of the piston; it's soft and will wear with time. JMS uses these coated pistons often and sets the hone accordingly.
While the block was being prepped, JMS's Howard Allen was inspecting our crank, and as we'd hoped, it only needed to be polished. After Howard had the journals looking as if they were chromed, he remeasured to verify the dimensions, and as predicted, it was still well within standard spec.
The techs at Federal-Mogul told us that the H100CP hypereutectic pistons we were using were intended as a performance application, which meant (among other things) that they shouldn't fall too deeply into the bores at TDC, like most "rebuilder" pistons do. Their estimate placed the piston 0.020-0.025 inch "in the hole" with a mild skim of the block decks. Since we planned to run 64cc Vortec heads and 0.015-inch steel-shim head gaskets, that would give us around 10.5:1 compression and sufficient piston-to-head clearance. Sal performed the minor decking, which took 0.007 inch from one deck and 0.009 inch from the other (to even them out). Later, we mocked up the short-block and found the pistons to be 0.024-inch down, giving us 0.039-inch piston-to-head clearance (Federal-Mogul says 0.035 is the minimum) and a calculated 10.4:1 compression.
Having the stock connecting rods reconditioned would have cost about $80, and we'd have wanted to upgrade the rod bolts, which would've added another $40-$50. Instead, we opted for a set of used GM powdered-metal rods from a late-LT1 engine. Chevrolet says they are stronger than the factory pink rods and have high-grade fasteners. Best of all, we could purchase them for the same dollars that would have gone toward reconditioning the stockers. Notice the lack of a balance pad on the big end--GM felt these rods were so uniform that the pad was unnecessary. Indeed, ours checked out to be within 3 grams of each other, but the JMS crew shaved them to a perfect match anyway.
With the crank cleaned and the rods weight-matched, the pistons, pins, and rings were weighed to verify that they also matched as promised on the Speed Pro box (they did) and then the crank was assembled with bob weights on the spin-balance rig. This is an expense that is usually considered optional, though since we were changing the rods as well as the pistons, we felt it was necessary. If you're building a performance engine, spend the extra cash for the balance job.
Once the rotating assembly was balanced, JMS hung the pistons on the rods and it was finally time to start putting it all together. Out of the three Titan engines, the Chevy was obviously the easiest to build on a budget, which left us with a few bucks for accessories. One of the extras we sprang for was a Milodon windage tray, which necessitated a special main-stud kit, also purchased from Milodon. After the crank was set in place, the studs were threaded in by hand, and then the caps were installed and torqued. As a bonus, the stud kit will also provide extra strength to our bottom end. The improved oil control offered by the windage tray should add a few more ponies too.
Once JMS buttoned up the bottom end, we moved to the all-important camshaft. Since we were limited to hydraulic flat-tappet cams by the rules of the competition, we selected one of Crane's Saturday Night Special grinds to make big torque and horsepower in the upper-rpm range. The shaft is ground for 244/252 degrees duration at 0.050-inch lift and 0.516/0.525-inch lift on a 106-degree lobe separation angle. We checked it with a degree wheel to verify its placement and briefly considered advancing it to further boost low-end torque (our Cloyes timing set allowed 4 degrees). Upon further inspection of the specs, however, we decided to merely install it straight up as Crane intended.
The plan called for Vortec heads, but there was a potential flaw with that approach. From the factory, the Vortecs can only handle a maximum of 0.470-inch lift without bottoming the valvespring retainers against the tops of the valveguide seals. In addition, the factory springs were not designed for high-lift or long-duration lobe profiles, which we fully intended to use. These issues can be dealt with by having a machine shop machine the valveguides and install better springs, but we found the simpler solution was to purchase upgraded heads from Scoggin-Dickey Parts Center in Lubbock, Texas. Scoggin-Dickey offers its own version of the Vortec with Z28 valvesprings and LT4 retainers, which are both lighter (to improve rpm capability) and shallower (to provide extra retainer-to-guide clearance). We had JMS verify the claims, and as promised, the heads were good for 0.525-inch lift.
As mentioned, we wanted to get the maximum compression out of the combination, so we used Fel-Pro's 1094 head gaskets, which are rubber-coated steel shims that have a compressed thickness of only 0.015 inch. A typical composite gasket would be about 0.042 inch. These gaskets coupled with the Vortec's 64cc combustion chambers and the 5cc valve reliefs of the Speed Pro pistons, plus the 0.024-inch depth of the pistons, should give us 10.4:1--just about as far as you'd want to go with iron heads on pump gas. This approach will also allow us to reduce compression later if necessary by simply using a thicker head gasket. Milodon head bolts provided the clamping.
We thought about investing in 1.6:1 roller-rocker arms (1.5:1 is stock for the small-block Chevy) but found that the increased valve lift wouldn't work with our Vortec heads and this particular cam. We could have gone with 1.5:1 rollers, but the Vortec heads require self-aligning rockers, which should also be a narrow-body design to clear the center-bolt valve covers. Crane offers the perfect solution in its Gold Race Extruded line (PN 10751 for 1.5:1, PN 10758 for 1.6:1), but they cost $310, which seemed extravagant for our meager budget. Instead, we went with a fresh set of stock GM stamped-steel self-aligning arms. The set of 16 new genuine GM rockers complete with new balls and nuts was only $50 from Scoggin-Dickey.
The cherry on top is the Edelbrock RPM Air-Gap intake manifold. Our rules stipulated a dual-plane design, and the RPM line consistently shows excellent results over a broad range of engine rpm. The Air-Gap makes that even better by separating the intake runners from the base to isolate them from the engine's heat. When we get to the dyno, we'll mount the same 750-cfm Road Demon carb that was used on the other engines, along with a set of Hooker long-tube headers and an MSD distributor.
|Chevy 350ci Price List |
|Unless otherwise noted, all prices are from JMS Racing Engines, Scoggin-Dickey, Northern Auto, and Summit Racing as of June 20, 2003, and are subject to change. Taxes, shipping, and installation charges are not included. |
|Manufacturer ||Description ||PN ||Price |
|Crane Cams ||High-perf hardened pushrods ||95633-16 ||$150.39 |
|Edelbrock ||Performer RPM Air-Gap Vortec manifold ||7516 ||219.95 |
|Fel-Pro ||Steel shim head gaskets ||1094 ||39.90 |
|JMS Racing Engines ||Used GM powdered-metal connecting rods ||NA ||80.00 |
|Northern Auto Parts ||Engine kit (pistons, rings, rod, mains and cam bearings, cam kit, gasket set, freeze plugs, timing set, and oil pump) ||Call ||410.95 |
|Modified Vortec heads ||SD8060A ||632.00 |
|GM Vortec intake gaskets ||12529094 ||18.85 |
|GM guided stamped rockers ||1249540 ||49.95 |
|Oil pan ||30700 ||75.95 |
|Windage tray ||32100 ||21.95 |
|Windage tray stud kit ||81150 ||41.95 |
|Swap Meet ||Chrome valve covers ||N/A ||25.00 |
|Parts Total $1,766.84 |
|JMS Racing Engines |
|Hot tank || ||$35.00 |
|Bore and hone || ||120.00 |
|Block deck || ||60.00 |
|Spin balance || ||150.00 |
|Install pistons on rods || ||32.00 |
|Polish crankshaft || ||25.00 |
|Labor Total $422.00 |
|Final Total $2,188.84 |
Summit Racing Equipment
P.O. Box 909
26555 Northwestern Hwy.
530 Fentress Blvd.
2250 Agate Ct.
Scoggin-Dickey Parts Center
Northern Auto Parts (NAP)
JMS Racing Engines
2700 California St.
26555 Northwestern Hwy.