Making power is easy. It’s only a matter of understanding what you want and how far you’re willing to take it.
If you recall, back in the Mar. ’12 issue (“The Bigger Mouse”), we ordered a complete Dart 434ci SHP short-block stuffed with all forged internals, had 10.3:1 compression, and a COMP hydraulic roller camshaft. Up top, we completed the package with a set of Dart CNC 227 cylinder heads and fed the fire with a Holley Ultra HP 750 carburetor.
When Westech Performance Group’s SuperFlow 902 put our mill to the test, the end result was 542 hp/552 lb-ft on pump gas. Again, our intentions were to build a real-world street mill that could idle, be driven anywhere, and have big-block–like torque, with a healthy rumble.
Holley’s aluminum Ultra HP...
Holley’s aluminum Ultra HP carbs are a choice lineup. These mixers weigh in at just 8.5 pounds and come with a host of features, including billet aluminum metering blocks and baseplates, and completely redesigned fuel bowls. Plus, we dig the Hard Core Gray hardcoat anodized finish.
Since then, we’ve decided to maintain the core of the combination and only port-matched the intake manifold (“Max Flow,” Jun. ’12, pg. 20). For the second round, we wanted to see what this gem would produce with a mild hit of nitrous; our system of choice was a Nitrous Oxide System Cheater kit, which is good for an additional 100-250 hp.
Also, at the recommendation of Westech’s Steve Brulé, we swapped out the original Holley Ultra 750 HP for a 950 version. While the 750 worked well, Brulé felt the 434 would benefit from the larger carburetor. All said and done, between the port matching and the 950 hp, our baseline numbers improved 13 hp and 6 lb-ft to 555 hp/558 lb-ft.
The naturally aspirated numbers are impressive, but wait until you take a look at the nitrous results. Where do we go from here? Time will tell, but we think you’ll like what we have planned. Until then, read on to see how to transform a mild street combination into a track terror on command.
|Bore x Stroke
||4.155 x 4.000 inches
|Piston deck height
|Rod bearing clearance
|Main bearing cap torque
||1-5 / 7/16 bolts / 65 ft-lb (moly-lube)
| 2, 3, 4 / 3/8 bolts / 35 ft-lb (moly-lube)
|Rod bolt torque
||70 ft-lb (moly-lube)
|Head bolt torque
||80 ft-lb (moly-lube)
Another feature we like is...
Another feature we like is the built-in fuel bowl drain plug. This makes messy jet changes a thing of the past.
To expel the spent fumes,...
To expel the spent fumes, we used a set of 13/4-inch long-tube headers with 18-inch extensions.
Eddie Motorsports supplied...
Eddie Motorsports supplied these trick-looking valve covers. Priced at just $110 with your choice of color (laser engraving starts at $30), they can laser etch any design, as long as you submit the artwork.
We placed the injector plate...
We placed the injector plate underneath the spacer; the red port is for the fuel side and is where the fuel jet is inserted. Once the appropriate jet for the horsepower rating is in place, the braided line is then connected.
Each kit includes a nitrous...
Each kit includes a nitrous and fuel solenoid good up to an additional 250hp hit.
NOS offers a black anodized...
NOS offers a black anodized billet solenoid bracket that’s laser engraved and makes mounting the solenoids a breeze.
1. Dart SHP block with a 4.155-inch bore // 2. Dart single-plane manifold/Nitrous Oxide Systems Competition Cheater Plate System (PN 02010NOS) // 3. 13/4-inch headers with 18-inch extensions and mufflers // 4. Dart CNC 227 cylinder heads // 5. Holley Ultra HP 950-cfm carburetor (PN 0-80805HB) // 6. Eddie Motorsports custom-engraved valve covers