Small-Block Showdown – Battle Of The TCI Engineering Project Engines

Inter-office rivalries are a part of life. Especially when that office happens to be the hot-rod parts manufacturer Total Cost Involved Engineering. So it comes as no surprise that when two of the company’s demo cars/test mules – which happen to be nearly-identical twins – were due for engine rebuilds, and someone found out how similar the two small-block Chevrolet engine builds were going to be – even though one was a first-gen SBC and the other a fourth-gen LS – a rivalry was born.

Party number-one to the shenanigans is Evan Dalley, the Sales Manager for TCI Engineering. The other half is Andy Mule, a retired machinist who has been flying the TCI Engineering banner for longer than anyone cares to admit. Both enthusiasts have  Chevrolet Nova sedans – Dalley’s a ’63 and Mule’s a ’66 – with identical suspensions and drivelines, save for the engines, making for a very unique showdown.

Dalley’s choice of powerplant is a traditional small-block Chevrolet, while Mule has opted for an LS3 powerplant. As you’ll see, the displacements between the two only differ by three cubic inches. Both engines have cylinder heads from Air Flow Research, and the same 12.0:1 compression ratios, along with 950 cfm carburetors. However, one notable difference is the fuel, the LS will be run on pump 91-octane, while the SBC will be gulping down E85.

So while the main purpose of this “competition” is bragging rights amongst friends, it’s also a very unique opportunity to compare the original small-block Chevrolet V8 against the Bowtie’s modern iteration of the small-block.

Evan’s Small-Block Chevrolet

Designed from the beginning by Caldwell Racing Engines to be a stout engine, the core of the build is one of the most reliable engine blocks around – a Dart Iron Eagle. The extremely capable block was punched out to a finished bore size of 4.155 inches by HPS Machine, and a Scat 4.00-inch stroke crankshaft was dropped into the Clevite main bearings for a classic 433 cubic inches of displacement.

Forged 6.00-inch Eagle H-beam connecting rods were chosen for the combination, with Mahle PowerPak pistons hanging off the end of them. To seal the pistons in the bore, Caldwell opted for the Mahle PowerPak ring package for the combination. A Milodon oil pan seals up the bottom end, while a Melling oil pump keeps the lifeblood of the engine flowing to all the critical areas.

For the bottom end of Evan’s SBC, the team used a Dart Iron Eagle block, a forged Scat crankshaft, forged Eagle H-beam rods, and Mahle PowerPak pistons. A simple, reliable combination that will hold up to everything asked of it.

Topping off the short-block are a set of cylinder heads truly worthy of the adjective “badass.” The aluminum Air Flow Research 245cc Eliminator spread-port race heads are impressive out-of-the-box, flowing 345 cfm through the intake ports and 250 cfm through the exhaust, but these particular heads have had the ports further worked-over by Caldwell, to an undisclosed size and flow-rate. With the 70cc CNC’d combustion chambers, the engine’s compression is right at the 12.0:1 mark.

Both the 2.125-inch intake valve and 1.600-inch exhaust valve use a single bead lock groove on the 8mm stem, to go with the 10-degree bead lock keepers and 10-degree titanium retainers. PAC Racing 1.550-inch OD dual valve springs feature 250 pounds of seat pressure, and are advertised as good up to .800-inch of lift, and 8,200 RPM.

The 4.155-inch Mahle PowerPak pistons feature a 4cc dome to bump the compression up to 12.0:1, along with a 1.0mm top and second ring, with a 2.0mm oil ring.

A Caldwell custom specified camshaft, measuring in at “two-fifty-something” degrees of duration on both the intake and exhaust, with .670-inch of lift and a 108-degree lobe separation angle controls the valve timing. Comp Cams solid roller lifters ride the cam lobes, and move the 5/16-inch Manley pushrods. Those actuate the 1.6: Crower shaft mounted rocker system.

Sitting atop the cylinder heads is an Edelbrock Super Victor intake manifold with a Quick Fuel Technologies 950 cfm Q-series E85-specific carburetor feeding the beast. Caldwell Performance and TCI Engineering collaborated on the headers, and a classic MSD 6AL ignition box keeps the candles lit under the most severe conditions.

The Air Flow Research 245cc spread port Eliminator heads use Crower stainless shaft rockers, an Edelbrock Victor intake, topped off with a Quick Fuel Technologies E85 Q-series carb. The combination made for a smooth power curve which made power up to 6,800 rpm on the dyno.

Andy’s Generation IV LS3

In the other corner, and at the other end of the small-block Chevrolet spectrum is Andy Mule’s LS3 build. Andy and the team at HPS Machine decided to use a factory LS3 aluminum engine block as the basis for the Gen IV small-black build. With only a mild overbore of .015 inch, the combination features a 4.075-inch bore, with a Scat 4.125-inch stroke crankshaft sitting in ACL main bearings, for 430 cubic inches of displacement.

A set of forged-steel 6.125-inch Scat H-beam connecting rods attach the 4.075-inch custom Racetec pistons to the forged crankshaft. Again, a Milodon oil pan was used on the LS, and a high-volume, high-pressure Melling 10296 oil pump was used on the LS build to keep a sufficient amount of oil moving through the system.

The LS3 short-block started with a mild overbore of the factory aluminum block, Scat forged 4.125-inch cranshaft, forged 6.125-inch Scat H-beam rods, and ACL bearings throughout.

On top of the short-block sit AFR’s pinnacle LS cylinder heads – the LS3 Mongoose 12-degree cylinder head. Cast from A356 aluminum, they feature completely CNC-ported intake and exhaust valves straight from AFR. The intake port measures a whopping 260cc of volume, and flows 384 cfm. The exhaust port measures in at 95cc and flows an impressive 255 cfm.

The CNC’d combustion chambers of the Mongoose heads measures in at 69cc, which makes for an identical 12.0:1 compression ratio. Featuring a slightly larger intake valve than the gen-one SBC at 2.165 inches in diameter, the exhaust valve is the same 1.600 inches. Both intake and exhaust valves have an 8mm stems.

The PAC Racing dual valvesprings are designed for use with hydraulic roller applications, and feature 155 pounds of seat pressure. Like the SBC’s valves, these use a single bead lock groove, but unlike the SBC, the Mongoose 12-degree valves use 7-degreee titanium spring retainers and locks.

AFR’s 260cc Mongoose 12-degree LS3 heads are seriously badass heads, and were paired with Crower’s equally-badass stainless shaft rockers. Out of the box, the heads flow 384 cfm through the intake port and 255 through the exhaust port.

The camshaft chosen for the LS3 is from Isky Racing Cams, and is actually a bit smaller than the SBC’s, featuring 243 degrees of intake duration, and 254 degrees on the exhaust side, with .625-inch lift at the valve and a 110-degree lobe separation angle. Lunati hydraulic lifters ride on the cam lobes, and the 5/16-inch Manley pushrods actuate the Crower 1.7:1 ratio shaft rocker system.

Feeding the heads is a Quick Fuel 950 cfm Black Diamond Q-series carburetor tuned for 91-octane pump gas sitting atop an Edelbrock Victor Jr. LS3 manifold. 1-7/8-inch Doug’s Headers get the spent exhaust gasses out of the engine, while an MSD 6AL ignition keeps the spark going, the same as was used with the small-block Chevy.

Using an Black Diamond Q-series 950 cfm carb from Quick Fuel Technologies tuned for 91 octane, on top of an Edelbrock Victor Jr. carb intake manifold, the combination breathes quite will in the upper RPM range.

The Results

Right off the bat, we need to be upfront in that Evan’s small-block Chevrolet got far more time on the dyno than Andy’s LS3. It was the first of the two engine’s dynoed and here was a lot of tuning and tweaking performed during it’s time on the dyno. That included switching to a thinner oil, which ended up being worth 15 horsepower.

At the end of it all, the AFR-headed 427-cube small-block Chevy put down an impressive 640 horsepower at 6,700 rpm, and 578 lb-ft of torque at 5,000 rpm, with 450-plus lb-ft from 3,500 rpm with a smooth power curve that pulls all the way to 6,800 rpm.

Andy’s LS3, on the other hand, only got the benefit of 5 dyno runs, two of which were only to 5,000 rpm. There was a midrange carb-jetting issue, and a collapsed hydraulic lifter that were plaguing Andy and team during their power runs.

With that said, the team noted the engine’s weak midrange, but felt that the top end wasn’t impacted. With a peak horsepower of 670 at 6,400 rpm, and peak torque of 600 lb-ft at 5,300 rpm, the LS3 can claim the title of TCI Engine Shootout victor!

However, that’s not the last you’ll see of this LS3, as immediately after coming off the dyno, the LS3 was sent back to the assembly room at HPS Machine to be upgraded to a solid roller configuration. Once that’s completed, you’ll likely see a comparison between the hydraulic and solid roller results in an upcoming article.

As you can see, while the Gen-I SBC has much smoother power and torque curves, that is due in part to the extended amount of dyno time the SBC got, and the fact that the the LS had a collapsed lifter and some midrange fueling issues. Five runs simply weren't enough to do anything but determine max power, where the LS3 shined.

Article Sources

About the author

Greg Acosta

Greg has spent over a decade in automotive publishing as Senior Editor of Race Pages magazine. In his free time, he is a firearms instructor and volunteer in the police armory.
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