Oldsmobile 455 Big Block Engine Build - Car Craft Magazine

On the street, torque is king. One of the best and simplest ways to make gobs of frame-twisting torque is with cubic inches. Among the torque kings in the GM world are the Buick, Pontiac, and Olds 455ci twisters, but it's often the Olds that wins out. While the good Dr. Olds factory variants have been the staples of Rocket performance building for decades, Edelbrock's aluminum head contribution has made building one of these big-blocks enticing and weight conscious. So when it came time to freshen up the tired 455 in our budget '64 F-85 Olds project, we learned a few assembly tricks for our fat-block we thought we'd pass along that will ensure our Olds lives a long and prosperous life-and makes some acceptable power, too.

With our Rocket 461-inch motor assembled, it will be an easy evening's work to swap in our lighter and more powerful Edelbrock aluminum-headed 461ci thruster using a set of coated 1 3/4-inch Dick Miller Racing headers.

The plan was a much more street-conservative approach versus our usual max-out horsepower effort-more of an everyman's big-block. We wanted a daily-driver engine with pump-gas-friendly compression and a Comp flat-tappet hydraulic cam to enhance the Olds' already legendary torque. We really enjoy cruising the F-85 with its patina paint, so future plans include either a tight converter combined with a California Performance Transmissions 200-4R overdrive automatic, or maybe we'll retain the TH400 and just slip a 2.56:1 rear gear behind it. Either way, our recipe called for a motor that would make stupid low-speed torque while still pushing our F-85 to mid-12 quarter-mile times. All this was also with an eye toward not destroying what was left of our meager car budget.

Since we had never assembled an Olds motor before, we relied heavily on advice and assistance from Don Barrington at Barrington Engines and Dick Miller Racing (DMR), whose Mississippi-based shop offers tons of options for the Rocket engine builder. Barrington and Miller helped us avoid the common assembly mistakes on our 461ci street engine, and much of the success of this engine is due to their significant contributions.

After cleaning the block, Barrington bored the block 0.030 over and torque-plate-finish-honed each cylinder to fit the 4.155-inch-bore-size hypereutectic pistons.

Search and Destroy
While it would have been cheaper to rebuild the existing 455 in the '64 F-85, we knew the build would take some time, and we wanted to continue to drive the car. We found a used 455 short-block on Craigslist that got us started. The crank was wasted, but for $200, we bought the short-block and an extra crank that we discovered had a trashed thrust surface. Engine and Performance Warehouse in Anaheim, California, repaired our ailing crank and gave it a perfect 0.010-under treatment. We then took the block, crank, rods, and pistons to Barrington Engines where Don Sr. and Don Jr. cleaned, bored, and torque-plate-honed the aging jet-boat motor. West Valley did the balancing act.

One trick Barrington and Miller suggested was replacing the stock Conestoga wagon-era rope rear main seal with a neoprene lip seal from a 460 Ford. Next, the guys encouraged us to add cam bearing restrictors that direct more oil to the mains. Our next surprise came with the rear main bearing clearance measuring a wide 0.0041 inch. Barrington says this was factory intentional to flood the rope seal with oil to prevent it from overheating. Barrington suggested we retain the clearance because it would require expensive line boring to repair, so we followed his advice. We've also outlined a couple of other Olds-specific assembly techniques that can save you some grief when assembling a street Rocket.

Edelbrock Aluminum Heads
Our own flow testing and DMR's experience showed us that the off-the-shelf Edelbrock aluminum Performer RPM heads flow about the same as a set of factory iron C heads. This limited flow is partly due to the requirement that the ports (especially the exhaust) remain in their stock locations. We wanted to improve on the intake flow slightly without spending big bucks for CNC porting, so we tried the classic 30-degree back-cut trick on the Edelbrock valves, which netted a minor flow improvement. The Edelbrock heads measure 77 cc and combined with the 15cc dished KB pistons create a 10.2:1 static compression.

Flow Chart
Edelbrock Performer RPM Olds Aluminum Head
2.07/1.68-inch valves (PN 60519 complete)
77cc chamber
188cc port

VALVE LIFT INTAKE EXHAUST EXHAUST TO INTAKE RESULT
OPEN WITH PIPE INTAKE 30-DEGREE BC (CFM) (CFM) (CFM) PERCENT (CFM)
0.050 34 25 73 -- -- 0.100 70 53 76 70 -- 0.200 137 95 69 144 + 7 0.300 195 132 67 206 +11 0.400 234 168 72 246 +12 0.500 240 185 77 237 - 3 0.600 245 194 79 239 - 6

A simple 30-degree back-cut on the Edelbrock intake valves was worth as much as 12 cfm at 0.400-inch valve lift. The production 455 head we tested at 0.400-inch valve lift flowed only 190 cfm. Our modified Edelbrock's amazing 56-cfm flow improvement at 0.400-inch valve lift is a 29 percent gain over the stock heads.

Cam Specs

COMP XE-268-H-10 DURATION DURATION LIFT LOBE
DEGREES DEGREES (INCHES) SEPARATION (ADVERTISED) (AT 0.050)
Intake 268 224 0.485 110 Exhaust 280 230 0.490

Test Day

Edelbrock agreed to help us with the dyno testing, and Edelbrock dyno veteran Curt Hooker bolted our 461ci Rocket to the company's SuperFlow dyno. Before firing the engine, we pressure-lubed it with a homemade tool that really was nothing more than a 6-inch-long Allen bolt. The bolt head is used to spin the hex drive oil pump driveshaft. After properly timing the Performance Distributor D.U.I. HEI distributor, Hooker carefully broke in the Comp flat-tappet camshaft for roughly 20 minutes using Royal Purple's 10W-30 break-in oil.

Test Day
Edelbrock agreed to help us with the dyno testing, and Edelbrock dyno veteran Curt Hooker bolted our 461ci Rocket to the company's SuperFlow dyno. Before firing the engine, we pressure-lubed it with a homemade tool that really was nothing more than a 6-inch-long Allen bolt. The bolt head is used to spin the hex drive oil pump driveshaft. After properly timing the Performance Distributor D.U.I. HEI distributor, Hooker carefully broke in the Comp flat-tappet camshaft for roughly 20 minutes using Royal Purple's 10W-30 break-in oil.

Big-block Olds engines are famous for making torque, and this combination was no exception. Even at a mere 2,500 rpm, the Olds cranked out nearly 490 lb-ft, then went on to grunt out a solid 511 lb-ft at 3,700 rpm, and still managed to make a solid 445 hp at 5,000 rpm. The torque was expected, and we hedged our bet a little by trying the Edelbrock Torker single-plane intake to see if we could give the horsepower a bump. If you look closely at the torque numbers, you can see a slight dip in the curve between 3,800 and 4,500 rpm that may be due to a combination of the single-plane intake and the large 2.00-inch dyno headers. We would expect some if not all of that dip to disappear in the car with the use of our Dick Miller 13/4-inch headers and a muffled Flowmaster exhaust. We'd like to thank Edelbrock and specifically Curt Hooker for his time, expertise, and the benefit of his expansive experience that made our dyno flog much easier. Real-world dyno numbers are always better than best guesstimates. Overall, the effort was a great success, and now all we have to do is drop it into our '64 F-85 and enjoy all that torque.

Dyno Results

RPM TQ HP 2,500 488 232 2,700 482 247 2,900 470 259 3,100 468 276 3,300 484 304 3,500 499 332 3,700 511 360 3,900 493 366 4,100 473 369 4,300 475 389 4,500 498 426 4,700 492 440 4,900 473 442 5,100 456 443 5,300 423 427 5,500 408 428 Peak 511 at 3,700 445 at 5,000 Average 474.5 358.7

Parts List

DESCRIPTION PN SOURCE PRICE Edelbrock RPM heads 60519 Summit Racing $1,651.00** Edelbrock Torker intake 2730 Summit Racing 285.95 Edelbrock valve covers 4485 Summit Racing 45.95* Holley 750 vac. sec. carb 0-80508S Summit Racing 299.95 Holley mechanical fuel pump 12-836 Summit Racing 69.95 Keith Black hyper piston KB277-030 Summit Racing 309.95 Sealed Power ring set E-243X-30 Rock Auto 44.79 Federal-Mogul main bearings 108M-10 Summit Racing 103.39 Federal-Mogul rod bearings 83345P Rock Auto 70.99 Sealed Power cam bearings 1234M Rock Auto 33.79 Fel-Pro full gasket set FS8171 PT-4 Rock Auto 70.79 Neoprene rear main seal 40032 DMR 16.95 Milodon oil pan, 7-quart 30305 Dick Miller 255.00* Milodon windage tray 32225 Summit Racing 56.95* Milodon oil pump pickup 18411 Summit Racing 42.95* Milodon oil pump shaft 22575 Summit Racing 21.95 Milodon brass plug kit 34045 Summit Racing 14.95 Melling oil pump M-22FHV Summit Racing 59.95 Comp hydraulic cam, lifters CL-42-223-4 Summit Racing 209.95 Comp timing set 2113 Summit Racing 41.95 Comp pushrods, 0.100 long 7664-16 Summit Racing 116.95 Comp 1.6:1 roller rockers 19044-16 Summit Racing 299.95 Professional Products balancer 80022 Summit Racing 84.95 ARP rod bolts 185-6001 Summit Racing 58.95 ARP head bolts 180-3600 Summit Racing 75.95 ARP balancer bolt 180-2501 Summit Racing 19.95 DMR oil restrictor kit DMR-5104 Dick Miller 33.00 DMR oil pump shim DMR-5110 Dick Miller 19.00 DMR cam thrust button kit DMR-5745 Dick Miller 54.00* DMR front oil gallery plugs DMR-7020-7021 Dick Miller 31.13 DMR fuel pump eccentric N/A Dick Miller 23.00 DMR lifter valley tray DMR5850 Dick Miller 54.00* DMR two-piece timing cover N/A Dick Miller 119.00* DMR water pump N/A Dick Miller 139.00 DMR headers DMR6821 Dick Miller 682.94 Performance Distributors HEI 42720 Performance Distributors 305.00 Dupli-Color Gold paint DE1604 Summit Racing 6.95 Bosch standard spark plugs FR8DS Rock Auto 28.24 Fram oil filter PH25 Rock Auto 4.49 Quaker State oil, 6 quarts 10w30 Local auto parts 19.50 Subtotal $5,883.05 Barrington machine work Clean and mag block N/A Barrington 100.00 Bore and torque-plate-hone N/A Barrington 290.00 Resize rods, install bolts N/A Barrington 100.00 Machine side clearance N/A Barrington 50.00 Balancing N/A West Valley 200.00 Grand total $6,623.05 Mark 7 Radiator Call Mark 7 650.00

*These components could be deleted from the buildup to save money. Subtracting these parts from the overall cost would reduce the price by $627.85.
**This price includes Edelbrock's $50 rebate. Plus, you get a couple of Edelbrock T-shirts, too!