Exclusive Content
Original Shows, Motorsports and Live Events
Try it free for 14 days
Due to the EU’s Global Data Protection Regulation, our website is currently unavailable to visitors from most European countries. We apologize for this inconvenience and encourage you to visit www.motortrend.com for the latest on new cars, car reviews and news, concept cars and auto show coverage, awards and much more.MOTORTREND.COM
Subscribe to the Free

How To Build A 525ci Big-Block - Big-Inch Punch

How to Build 1,700-Plus Horsepower with a Blown 525ci Big-Block

View Full Gallery

The last time you saw our Dart-based 454ci big-block, we generated 965 hp and 877 lb-ft (“Off-The-Shelf Steam” Apr. ’11 issue). For induction duties we used a pair of Brodix CNC oval-port BB-3 332 Xtras and a Brodix HV 2000 manifold, while a Vortech YSi supercharger added the artificial atmosphere. Fueling the copious amount of air was a Carb Shop–modified Holley 750 carburetor.


For round two of our build, Vortech Engineering offered to let us try out its latest line of superchargers, namely the all-new V-28 123. This wild piece of hardware is good for impeller speeds up to 70,000 rpm (rumors say significantly more), it features a 123mm billet impeller, and the peak power level is still yet to be determined. Knowing it would take a fairly stout bottom end, we decided to transform our 454ci into a 525ci stroker, using a complete Lunati bottom end consisting of a Pro Blower series crankshaft with their 4340 fully machined I-beam rods, and a set of JE pistons. For induction duties, we once again turned to Brodix and after a lengthy conversation, stepped up to the larger BB-3 380 Xtra cylinder heads. At the heart of the beast is a COMP Cams–built solid roller that we had spec’d out by Steve Morris Engines in Muskegon, Michigan. At The Carb Shop’s advice, we also stepped up to its 950-cfm carburetor with the dual needle and seat assembly.

The amount of power this gem was going to produce was seriously anyone’s guess. In our minds, we were shooting for anything over 1,500 hp and even scoured the ’Net looking for similar combinations. The truth is, at the time there were very few people with access to the V-28 123. If you recall, back in the July issue, we featured Chris Kephart and his ’62 Outlaw-classed Impala. Kephart has been at the forefront of testing the V-28 123 and is the first person to eclipse the 200-mph zone. Following suit, Chris Alston Jr. recently installed one into his ’64 Chevy II and shocked the doorslammer scene by becoming the first Vortech-powered car to dive into the 6s, running 6.71 at 213 mph right off the trailer!


It’s pretty evident to us that Vortech is onto something here, and we wanted to produce our own real-world evaluation, continuing with the off-the-shelf premise: no one-off components, no proprietary cylinder head porting, and—to challenge ourselves a little more—we wanted to generate a lot of boost through a single 4150 carburetor. It may have sounded like we were asking for trouble, but in all reality, it turned out to be one of the easiest big-horsepower combinations we’ve ever put together. Ridiculous? Even a bit arrogant? But it really was that easy. That’s not to say we didn’t run into our own issues, but these were things that were easily overcome; all of which we’ll go into greater details in the following pages.

Now, if there was one idealistic theme we wanted to stick with, it was to use the same manufacturers from the previous build with the addition of T&D shaft-mount rockers for valvetrain stability and Component Drive Systems’ geardrive to eliminate any belt issues. You have to hand it to our aftermarket; they offer top-notch components to support everything from a mild street package to dedicated track-only applications.


At the end of the day, we surpassed our goals and have to wonder, is this not enough power? Doubtful. Is this more power than most will know what to do with? That’s probably a bit more true. There’s nothing wrong with either answer, but chances are, our 525ci isn’t much different than what’s powering your street/strip project. However, it’s pretty amazing how easily a supercharger can conjure up a Jekyll and Hyde shift in demeanor on demand. Even better, everything shown here is currently available and only a phone call away.

Dyno Details

Size 525 ci
Intake Brodix HV 2000
Headers 21/8 Hedman long-tube headers with 18-inchextensions
Advance 34 degrees, pulled 1/2-degree per pound of boost
Fuel VP Q16
Carb The Carb Shop 950
Jets 82/86
Max. Torque 1,286 at 6,900
Max. Power 1,734 at 7,300
Avg. Torque 1,170
Avg. Power 1,329

Brodix BP BB-3 Xtra 380 Specs

Intake Port 380 cc
Chamber Volume 119 cc
Intake/Exhaust Valves 2.350/1.880
Exhaust Pattern standard
Valve Centerline standard

Dyno Details

4,500 959 821
4,600 986 863
4,700 1,013 906
4,800 1,039 950
4,900 1,055 984
5,000 1,075 1,023
5,100 1,089 1,058
5,200 1,105 1,094
5,300 1,112 1,122
5,400 1,119 1,151
5,500 1,133 1,186
5,600 1,136 1,211
5,700 1,155 1,253
5,800 1,168 1,290
5,900 1,181 1,327
6,000 1,198 1,368
6,100 1,216 1,412
6,200 1,229 1,450
6,300 1,243 1,491
6,400 1,257 1,532
6,500 1,268 1,570
6,600 1,278 1,606
6,700 1,281 1,634
6,800 1,284 1,662
6,900 1,286 1,690
7,000 1,282 1,709
7,100 1,277 1,726
7,200 1,258 1,724
7,300 1,248 1,734

Flow Data

Intake Exhaust
0.200 159 134
0.300 237 182
0.400 309 219
0.500 360 254
0.600 401 280
0.700 430 301
0.800 443 306
0.900 442 311
*cfm at 28-inch H20

Cam specs

Manufacturer COMP Cams
PN 11-000-9
Type Solid roller
Valve Lift 0.700/0.700 inch, intake/exhaust
Duration at 0.050 280/290 degrees, intake/exhaust
Lash 0.022/0.024, intake/exhaust
Lobe Separation Angle 112 degrees

Under pressure

RPM PSI (before cooler) PSI (after cooler)
4,500 11.12 8.76
4,600 11.72 9.13
4,700 12.29 9.55
4,800 13.01 10.02
4,900 13.5 10.41
5,000 14.2 10.83
5,100 15.05 11.26
5,200 15.75 11.73
5,300 16.44 12.15
5,400 17.39 12.62
5,500 18.07 13.25
5,600 18.98 13.85
5,700 19.79 14.5
5,800 20.67 15.06
5,900 21.63 15.65
6,000 22.61 16.39
6,100 23.58 16.92
6,200 24.53 17.62
6,300 25.53 18.27
6,400 26.6 19.09
6,500 27.66 19.79
6,600 28.85 20.5
6,700 29.74 21.34
6,800 30.99 22.08
6,900 32.01 22.89
7,000 33.35 23.69
7,100 34.41 24.35
7,200 35.49 25.09
7,300 36.33 25.3

Shaft-Mount Rockers

A shaft-mount rocker system’s job is to provide valvetrain stability in the upper-rpm range; however the added benefits can also result in a gain in horsepower by minimizing movement. While that may seem fairly obvious, we also learned that T&D Machine Products offers a variety of options to custom-fit any combination. Once we spelled out our goals, T&D recommended that we add the following options: First, the spring oil holes (PN 0720), measuring 0.040 inch and placed on the bottom side of the rocker. During the lift cycle, it’s constantly oiling the springs, helping to extend the spring life. The second option was the needle bearing tips (PN 0731); these feature 23 needle bearings in the roller tips and are recommended for high-lift applications and for endurance. Lastly, the steel rocker option (PN 0727); these are built out of billet chromoly, offering minimal fatigue with incredible strength in a lightweight construction. If you’re looking for a set for your mill, it’s definitely a good idea to call T&D directly.


525 Buildsheet

Displacement 525
Bore x Stroke 4.500x4.125
Compression 10:1
Rod center-to-center 6.385 inches
Piston Deck Height 1.332 inches
Chamber Volume 119 cc
Rod Bearing Clearance 0.0028 inch
Crank endplay 0.010
Piston Ring endgap Gapless top, 0.028 second
Main Bearing Cap Torque 110 ft-lb (moly-lube)
Rod Bolt Torque 70 ft-lb (moly-lube)
Head Bolt Torque 80 ft-lb (moly-lube)

Parts List




Aeromotive, Inc. 11107 Billet Hex Drive fuel pump
ARP 235-4302 Head studs
235-5603 Main studs
400-7614 Valve cover studs
400-1212 Header bolts
435-1902 Oil pan studs
230-7004 Oil pump stud
334-1401 Timing cover
430-3201 Water pump
430-3504 Starter bolts
435-2101 Intake bolts
400-2401 Carb studs
430-7401 T-stat housing bolts
430-1701 Distributor stud
135-2501 Damper bolt
135-7901 Oil pump drive
200-2902 Flexplate bolts
230-7303 Torque converter bolts
Brodix 2038116 BP BB-3 Xtra 380
HV 2000 manifold
COMP Cams 11-000-9 camshaft
948-16 springs
739-16 retainers
611-16 locks
518-16 seals
8996-16 Endure-X solid-roller lifters
8531-1 (8) 9.350-inch, pushrods
8512-1 (8) 8.550-inch, pushrods
6200 beltdrive
Component Drive Systems Call geardrive system
Dart 31273344 Big M Sportsman Block
Federal Mogul C141M main bearings
C87200CHA rod bearings
Fel-Pro 10751 (2) head gaskets
1275 intake gaskets
1412 exhaust gaskets
1884 R oil pan gasket
17936 valve cover gaskets
Holley 80496 950 hp
Moroso 20403 oil pan
22163 high-volume billet oil pump
25970 dipstick kit
38361 Oil pan stud kit
MSD 85551 Pro-Billet distributor
Lunati B2Custom 4.125-inch stroke blower series crankshaft
6385FM 4340 I-beam rod set
T&D Machine Products 3128 shaft-mount rockers
The Carb Shop Call blow-through modifications
Total Seal, Inc. CT9190-255 TNT piston rings
Vortech Engineering Call V-28 123 supercharger

Pressure Loss?

If we had one issue, it was not having a large enough air-to-water cooler. Since our geardrive was spinning the Vortech V-28 123 at its maximum recommended rpm, we were expecting to see boost levels at around 35 psi. Only, this wasn’t the case, and we were seeing 25 psi at best. To locate the pressure drop, we placed boost sensors before and after the air-to-water cooler and found an 11-psi difference. Interestingly, we were averaging 30-40 hp per 1 psi of boost, which tells us there’s a good chance we can still gain anywhere from 330 to 440 hp with an appropriately sized cooler. We’re pretty pleased with the results for the time being, but you can bet we’ll get our hands on the bigger cooler and see if our theory stands true. CHP


Mena, AR 71953
Comp Cams
Memphis, TN 38118
T&D Machine Products
Carson City, NV
The Carb Shop
Ontario, CA
Vortech Engineering
Oxnard, CA 93033
A.R.E. Performance & Machine
Simi Valley, CA 93065
Total Seal Inc
Phoenix, AZ 85027
Dart Heads
Troy, MI 48084
Component Drive Systems
(888) 388-0249
Steve Morris Engines
(231) 747-7520



Connect With Us

Get Latest News and Articles. Newsletter Sign Up

sponsored links