Olds 403 / 1977-79 Trans Am
Pontiac V8 Olds 403 / 1977-79 Trans Am
The Olds in the Trans Am — Olds 403 / 1977-79 Trans Am for Pontiac V8s
Open the hood on a 1977-79 Trans Am and you may not find a Pontiac at all. Late in the second-generation run GM filled a lot of those cars with an Oldsmobile 403, and almost nothing on it interchanges with a Pontiac V8. Rear main seals, distributor gears, head gaskets, heads and intakes are all Olds parts, and ordering Pontiac pieces for a 403 is the fastest way to end up with a return.
This page is the Olds 403 shelf. Butler stocks Edelbrock Performer RPM heads and intake, a Butler/Comp billet roller cam, lifters, Scorpion roller rockers, BOP distributor gears and Viton rear main seals, MSD ignition, gaskets, Butler CNC valve covers and a bolt-on top end package.
Browse Olds 403 / 1977-79 Trans Am Products
Items 1-19 of 19
Description: Olds 403 Polymer Dis. Gear -0.491 (Use with Factory GM HEI / Points & Mallory / Mallory Must Be Drilled for Larger Dia Pin)
Item #: BOP-ODG27
Condition:
New
Price: $199.95
Description: Olds 403 Polymer Dist. Gear - .500, for MSD, Pertronix, Holley, FAST Dist Only
Item #: BOP-ODG28
Condition:
New
Price: $199.95
Description: All New Butler Power Package for the 403 Olds. Bolt on Power
Item #: BPI-TEP-403
Condition:
New
Ships in 2-3 weeks
Price: $5,095.00
Sale: $4,995.00
Save: 2%
Save: $100.00
Description: Olds 403 Aluminum Valve Covers, 3.5", Add Custom Logo, Anodized Black or Clear (Set)
Item #: BPI-VC-403
Condition:
New
Price: $209.95
Description: Olds 403 Custom Billet Cam from Butler Performance with choice of lobe separation, smoother idle, a broader power curve, and more vacuum
Item #: CCA-OLDS-80xx
Condition:
New
Price: $529.95
Description: COMP Cams®Evolution Hydraulic Roller Lifters are the first lifters EVER created using the newly patented Hydraulic Cartridge Technology (HCT)! This revolutionary design offers the most reliable...More Details »
Item #: CCA-85701-16
Condition:
New
Price: $726.95
Description: Olds 403 Intake Gasket (Set) for use with Edelbrock heads 61025 and 61035
Item #: EDL-7238
Condition:
New
Price: $37.95
Description: Flowkooler high flow pump 1775 has a CNC machined billet impeller designed with an increased vane count and a reduced plate-to-impeller clearance. It achieves greater flow rates, higher head...More Details »
Item #: BRW-1775
Condition:
New
Price: $169.95
Description: Flowkooler high flow pump 1776 has a CNC machined billet impeller designed with an increased vane count and a reduced plate-to-impeller clearance. It achieves greater flow rates, higher head...More Details »
Item #: BRW-1776
Condition:
New
Not Available
Price: $172.95
Description: Olds 403 Ready To Run Street Pro Billet Dist w/ Built In Rev Limiter / Works With Or Without MSD Ignition Box (Magnetic Pickup / HEI Style Cap / NO Ignition Box Required / Use w/ coil # 8202 or Similar)
Item #: MSD-8529
Condition:
New
Price: $727.95
Description: Oldsmobile V8 403 1977-79
4.400 Bore
Silicone Beaded
Set/2
.040" Thickness
Item #: BGA-713G
Condition:
New
Price: $93.08
Description: *Hy-lift Johnson/Made In The USA* (Set/16)
.842" diameter; 97g weight; 2.05" OA height
Fits 78-79 Trans Am w/Olds 403
Item #: HLJ-951-16
Condition:
New
Price: $249.95
Description: Oldsmobile 403 Viton 2-piece rear main seal. NOT for Pontiac engines — Pontiac uses BOP-RMS01/RMS18 (3.00" main) or BOP-RMS02/RMS19 (3.25" main).
Item #: BOP-RMS03
Condition:
New
Price: $53.95
Description: The Edelbrock #61025 Performer RPM Cylinder Heads for 1965-76 Oldsmobile 400, 425 and 455 CID V8 engines is a perfect performance upgrade for big-block Olds-powered street machines and muscle cars. Set of 2
Item #: EDL-61025-2
Condition:
New
Price: $2,807.90
Free Shipping!
Description: For 350-403 c.i. Olds engines with a hydraulic roller cam, these heads are made of 356-T6 aluminum and feature 68cc chambers
Item #: EDL-61035-2
Condition:
New
Price: $2,493.90
Free Shipping!
Description: Butler modified these heads for direct bolt on to the OLD 403 c.i. engines found in the -1978-1980 Pontiac Trans Am
Item #: EDL-61035-403-2
Condition:
New
Price: $2,595.00
Free Shipping!
Description: Performer RPM Olds SB 403 Intake Manifold, 330-403 Engines, (Non-EGR)
Item #: EDL-7111
Condition:
New
Price: $492.95
Description: Pontiac Drop Base Shaker Assembly w/ 3" Cone Shaped Washable Element- For Use w/ Edel Perf RPM, Edel Victor Jr, and Northwind NW-4150 Intakes & QJET/Holley Carb 1973-79 TA 326-455
NOW WORKS ON OLDS...More Details »
Item #: PTF-EP-401
Condition:
New
Price: $259.95
Description: Oldsmobile Scorpion 1.6 Ratio *ENDURANCE* Series Roller Rockers (Set/16)
Includes Poly-Locks
7/16 Stud
Item #: SCP-SCP3051-16
Condition:
New
Price: $503.22
Items 1-19 of 19
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More About Olds 403 / 1977-79 Trans Am
1. Why Your Trans Am Has an Oldsmobile Engine
Plenty of owners find out the hard way. The car is a Pontiac, the badges are Pontiac, and the engine is an Oldsmobile 403 small block. Before you order anything, get this straight.
| Nothing here is a Pontiac part | the 403 uses Oldsmobile bore spacing, Oldsmobile heads and an Oldsmobile distributor and oil pump drive. Our 403 rear main seal is labeled Not Pontiac for exactly that reason. Cross-shopping a Pontiac 400 catalog will not work. |
| Small-block Olds, not big-block | the 403 lives in the Oldsmobile 330-403 family, which matters when you are reading Edelbrock part listings that also cover the 400, 425 and 455 big-block Olds engines. |
| It came out soft | Butler rates the factory 403 at only about 185 hp. That is the starting point, and it is also why almost everything on this page is about breathing. |
| The bore is 4.400" | our 403 head gaskets are cut for it, and they run .040" thick with a silicone bead. |
2. The Butler Edelbrock 403 Top End Power Package
If you want one part number instead of fifteen, this is the kit. It is a bolt-on top end for the 403 with the machine work already done, and Butler quotes it at upwards of 390 hp and 405 lbs tq when paired with a rotating assembly kit.
| What comes in it | Edelbrock small-block Olds heads, an Edelbrock Performer RPM intake port-matched in our shop, a Butler/Comp custom-grind hydraulic roller camshaft, Morel lifters, head gaskets, intake gaskets, exhaust gaskets, valve cover gaskets, a stainless intake bolt kit, an ARP head bolt kit and an adjustable pushrod length checker. |
| You choose the idle | the cam is offered on 114, 112 or 110 lobe separation. Wider separation idles smoother and makes more vacuum. Tighter separation gives the choppy idle and more midrange. |
| Options worth a look | CNC head porting to take flow up to 325-330 cfm, 5/16 pushrods, a BOP polymer distributor gear, 1.6 aluminum full trunnion rockers, a timing set, and the PTF drop base shaker unit to offset the taller intake height. |
3. Edelbrock Heads for the 403, and the Intake That Has to Go With Them
Head choice is the decision that trips people up, because Edelbrock catalogs these castings across the whole Oldsmobile range rather than by car.
| Performer RPM 61035, small-block Olds | 356-T6 aluminum, 68cc chambers, 200cc intake and 130cc exhaust port volumes, 2.072" intake and 1.680" exhaust valves in the factory 6 degree valve angle. They need a 3.9375" minimum bore, use a stud-and-guide-plate valvetrain with 3/8" pushrods, and have no heat crossover provision. |
| Performer RPM 61035-403 | the same casting, modified by Butler for direct bolt-on to the Olds 403 found in 1978-1980 Trans Ams. If you would rather not deal with the machine work yourself, order this version. |
| Performer RPM 61025, big-block Olds | a 77cc chamber head for 1965-76 Olds 400, 425 and 455 engines. It can optionally be milled for 1/2" head bolts to fit the 403. The smaller 68cc chamber on the 61035 raises compression, which is why Edelbrock points big-block owners at the 61025 instead. |
| The intake requirement | this is the gotcha. When you run the 61035 or 61025 head on a 403, the Edelbrock 7111 intake with port matching is required. Do not plan on keeping the factory manifold. |
| Performer RPM 7111 | a high-rise dual-plane manifold with a 180 degree firing order for 330-403 engines, non-EGR. It clears an HEI distributor and its carb pad takes a square-bore carburetor with no adapter. |
| Gaskets to match | we stock the Edelbrock gasket set for the Olds 403 with Edelbrock 61025 and 61035 heads, with a 1.95" x 1.56" port size. |
4. Camshaft, Lifters and Valvetrain
Butler stocks its own Comp grind for the 403 rather than making you wait on a custom order.
| Butler/Comp billet roller cam | a hydraulic roller on standard journals and standard firing order, 276/282 advertised, 224/230 at .050, and .503/.510 lift on 1.5 ratio rockers. Move to 1.65 ratio rockers and lift goes to .553/.561. |
| Degreeing it | Butler and Comp recommend installing the intake lobe centerline at 106 for the 110 separation grind, 108 for the 112, and 110 for the 114. Degree the cam, do not trust the dot. |
| Comp Evolution hydraulic roller lifters | .842" diameter, 2.130" seat height, .150" travel with preload between .050" and .100". Two warnings straight from the product data: they will not clear factory valley pans, and we recommend a .020 or .040 restricted pushrod with them. |
| Stock-style replacement lifters | for a 403 going back together as it was, the Hy-Lift Johnson hydraulic lifter set is .842" diameter, 97g, 2.05" overall height and is listed to fit 78-79 Trans Am cars with the Olds 403. |
| Roller rockers | Scorpion Endurance Series Olds rockers in 1.6 ratio, sold as a set of 16. |
5. Ignition, Drive Gears and Sealing
The parts nobody thinks about until one of them takes the engine out.
| BOP polymer distributor gear | carbon ultra-poly instead of bronze, so worn gears stop putting metal shavings in the oil. Two shaft sizes: .491" for stock-type distributors including factory GM HEI and points, and .500" for MSD, Pertronix, Holley and FAST distributors. Mallory units must be drilled for the larger diameter pin. |
| MSD Ready-to-Run distributor | a billet aluminum unit for the Olds 403 with a built-in rev limiter, an HEI-style cap and rotor, and a vacuum advance that can be locked out. Three wires and it runs, with no ignition box required, though it works with one. Use it with a coil such as MSD 8202. |
| Viton two-piece rear main seal | once asbestos left the factory rope seals, leaks became normal. The BOP Olds 403 seal is Viton and installs quickly. |
| Head gaskets | the 403 gasket set is cut for a 4.400" bore at .040" thickness with a graphite facing over a tang-perforated tin-plated steel core. Install them with a spray-on copper sealant and always re-torque. No short cuts. |
6. Valve Covers and the Drop Base Shaker
Two finishing pieces that have real fitment strings attached.
| Butler CNC aluminum valve covers | 3.5" tall, anodized black or clear, with a 1/4" thick gasket rail for a genuine sealing surface and stainless bolts included. You can choose a logo, and we can drill for breathers and oil fill or add custom engraving. They will not work with stock AC brackets, and a stud girdle requires the 3 1/2" tall covers. |
| PTF drop base shaker assembly | originally a Pontiac 400 and 455 piece, and it now works on the Olds 403. It is built for the Edelbrock Performer RPM, Victor Jr and Northwind NW-4150 intakes with a Q-jet or Holley carburetor, and it includes a 3" cone-shaped washable element. |
| Read the shaker exclusions | it will not work with a 301, a 350 Rocket, a 455 Olds or a 305/350 Chevrolet shaker, even if that is what left the factory in the car. Those shakers use different heights, offsets and base plates. You must cut the shaker for the air inlet, and it is not for high port heads. The early 1977 shaker was only 2" and may not work. |
The 403 is an easy engine to make good power with once you stop fighting it with the wrong catalog. If you are planning a build, tell us whether the car keeps its shaker, what intake you intend to run and whether you want the heads done here or shipped as castings, and we will get the combination lined up before parts start arriving.
Not sure what your Pontiac needs?
Email our tech team at tech@butlerperformance.com. Tell us your engine, heads, car, and power goal, and we will put the parts together as one combination that works.