From Popular Hot Rodding September 1994 Joe Mondello outlines the parts and proceedures required to get 493 inches and big torque from an Olds 455
In life, it is said there are only two sure things: death and taxes. And, if you're an Oldsmobile fan there are three: death, taxes and Joe Mondello.
Joe has been building high-performance Oldsmobiles for over 30 years now, and began his porting career at the age of 15, porting and relieving flathead Ford engines for Jack Kennedy Automotive.
During the '60s and '70s, Joe accepted a lot of Oldsmobile R&D work, which earned him the nickname "Dr. Olds," as well as a reputation for being "the man to see" when it comes to building an Oldsmobile engine. Indeed, even if you build a big Olds by yourself, there's no doubt it's going use some parts that Joe had a hand in designing. One of the most recent Oldsmobile combinations Joe came up with was a stroker 493 based on the 455 engine. Originally designed for customers who wanted maximum torque out of their motorhomes, Joe realized the 493 would be a great street/strip engine, capable of producing prodigious horsepower and torque at low rpm. Best of all the 493 requires no exotic or custom-made parts. You can get almost everything you need at the junkyard, so it isn't as costly to build as some other large-displacement engines. Joe supplied us with a complete parts list and his recommendations for this engine, so even if you don't live near Joe's new shop in Paso Robles, California, you can still take advantage of his experience.
MONDELLO OLDS 493 PARTS LIST
BLOCK: 1968-1976 Olds 455 block, cleaned and Magnafluxed for cracks. Sonic check is not
necessary; any 455 block will accept an .060 overbore without problems. Notch block for rod/crank
clearance. Remove excessive casting flash, V-out oil return at front of block. Deck for .020 negative
deck. Align hone if necessary. Use Mondello #ST-940 stud and strap kit. (Must machine .500 from main
caps #2, 3 and 4).
CRANK: #6165 nodular iron crank, Magnafluxed for cracks. Offset grind to 4.500 stroke, weld fillets
to improve strength and to narrow rod joumals for Buick V8 rods. Reduce counterweight diameter to
clear bottom of piston. Crossdrill, chamfer, heat treat, shot-peen and micro polish.
DAMPER: #8080, degreed OEM damper.
FLEXPLATE: Use either #8075 stock replacement or #OL-1200 FP bitlet steel inertia flexplate.
RODS: #MR-71 0-B 455 Buick forged steel rod, Magnafluxed for cracks. Polish beams, shot-peen, fit
with ARP rod bolts and resize. Grind sides for clearance and add side notches (.500 wide, .010-.012
deep, both sides).
PISTONS: #2065 Speed Pro/TRW piston. This piston, unmachined, will yield 10.5:1 compression with an
81 cc head. Hone pin holes to accept one-inch Buick wrist pin.
RINGS: #3070 +.065; Speed Pro plasma-moly ductile ring, file fit. .014-.01 6-inch top gap,
.010-.01 2-inch second, .01 5-.050-inch oil ring.
OILING SYSTEM: #SS-815. Comes with a high-volume, high-pressure Mondello blueprinted oil pump with
bolt-on 3/4-inch pickup tube and dual bypass spring, seven-quart, gold-irridited pan (one-inch lower
than stock). Use with WT-190 short or CT-850 full-length windage tray with WS-870 mounting hardware.
Use the ST-940-SOS stud and strap kit with CT-850 mounting hardware.
OIL GALLEY RESTRICTORS: #R-100.
CAM. JM-3-4 hydraulic (.522 intake, .542 exhaust, 230/238¡ of duration @ .050,110¡ lobe centers,
or, JM-4-5 hydraulic, (.542 intake, .558 exhaust, 238/246¡ of duration @ .050, 110¡ lobe centers).
With either cam, use SK-240S valve springs on "B" or "C" casting heads. Use HL-230 lifter or Crane
Hi-lntensity #99384 for increased vacuum.
CAM THRUST BUMPER: #TB-740. Eliminates cam walk and increases timing chain life
BRONZE CAM WEAR SPACER: #CS-120. If there is a timing chain gear alignment problem using the cam
thrust bumper and cam wear spacer, use Mondello CS-40 crank gear spacer.
CAM DRIVE: #TR-259 Cloyes True Roller set with nine-position crank gear.
CYLINDER HEADS: "B" or "C" casting heads with street-strip porting. Fill heatriser passage, weld
center divider in siamese exhaust port. Use #5270 2.07-inch Mondello Posi-Flow intake valves; run
Mondello hardened exhaust seats #1453 (for unleaded gas) with #52951 .68-inch Mondello Posi-Flow
VALVETRAIN: #7200 Mondello shaft-mounted aluminum roller rockers. Note: these rockers will only fit
under stock valve covers using Mondello extra-thickvalve cover gaskets #VC-538 and no baffles. You
may also use #VC-458 chrome valve covers without baffles, or #68300 extra-tall Moroso valve cover
(this valve cover will not fit under stock A/C or power steering brackets).
INTAKE MANIFOLD: Use #2151 Edelbrock Performer for mild street applications; for street/strip, use
#2730 Edelbrock Torker or #6109 Onffenhauser Port-O-Sonic.
CARBURETOR: #QJ-800-2 800cfm Quadra Jet by the Carburetor Shop or #4780-#4781 Holley 800 or 850cfm
IGNITION: If already equipped with HEI, use #AD-455 distributor, or use Mondello/MSD #ED-460 dual
magnetic pickup distributor with cap and rotor. Plugs into MSD SA, 6A, 6AL or 7AL box. Both distributors come with vacuum advance.
TIMING: 32-36¡ total (depends on the application).
HEADER SUGGESTIONS: Mondello #3202,1-7/8-inch header with 3 1/2"inch collector. Fits
1968-75 A-body. Large flange, will fit ported heads
GASKET SET: #OS-540, does not include shim valley pan gasket.
INTAKE GASKET: #MS-96004 steel shim "bathtub" gasket assembly.
ROD: #4065 tri-metal
MAIN: #4080 tri-metal
Rod Bearing: .002-.0025
Main Bearing: .002-.0025
Piston-to-Wall: .004 .0045
Piston-to-Valve: There is no need to worry about this clearance unless using a cam over 270 at .050,
and over .575 lift.
ENGINE CHARACTERISTICS: Engine will have a slightly racey idle at approximately 1000 rpm. Will
produce approximately 500 horsepower and 525 ft-lb of torque on readily available pump gasoline.
5500 to 6000rpm redline.