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Lee Atkinson's 455
Here it is folks, the particulars on the 455
that powers Lee Atkinson's 1967 Firebird. The car and 455 mill have
been discussed on the Performance Years and The Classical Pontiac Bulletin
Boards. This is a streetable 455 engine in a light bodied (3540 lbs with
driver) Firebird that turns low 12s in the quarter mile. (Lee
made it into the 11's --see stats below.) Yes, this is a streetable
Firebird. Questions? Contact Lee at : 67bird@symet.net
Technical
Block--455, 2 bolt mains
- Bore and stroke--4.15" x 4.21"--bored
.060 over to accommodate
forged pistons with moly rings
- Heads--#16 heads--3 angle, lightly surfaced;
2.11" and 1.77" valves (home ported by Lee)
- Valve Springs--installed height to match camshaft
lift (dual springs)
- Rocker Arms--Comp Cams--Magnum Roller Rockers
(1.52) with 7/16" rocker studs and 7/16" poly lock nuts
- Retainers--OEM
- Keepers--OEM
- Valve Seals--umbrella type/ intake/; o-ring/
exhaust--Fel Pro
- Lifters--Comp Cams hydraulic
- Push Rods--OEM
- Crankshaft--reconditioned; .020/.020 under;
journals polished
- Rods--stock reconditioned
- Rod Bolts--Milodon
- Pistons--TRW forged +.060; dished to lower
compression--9.92:1 with 16 heads
- Rings--moly--Sealed Power (Federal Mogul)
- Main Bearings/Rod Bearings/Cam Bearings--Clevite
- Timing Gear and Chain--double roller
- Gaskets--Sealed Power 260-1025 kit
- Camshaft--Ultradyne--231/ 239 degrees intake/
exhaust duration @.050; 288/296 intake/ exhaust, advertised duration; .485"
lift intake/ .507" lift exhaust; 108 lobe separation angle
- Intake Manifold--Edelbrock Performer RPM (also
has run the Torker II)
- Carburetor--Holley 750 Double Pumper
- Fuel Pump--Mallory 140 electricuel--93 octane
with booster additive
- Emission controls--pre-emission vehicle
- Exhaust manifold--headers of unknown origin
1.75"/ 3" collector running 3" exhaust pipe through two
2-chamber Flowmasters; balance pipe
- Oil location and filter--OEM
- All reciprocating parts are balanced; all
tolerances meet OEM specifications
- Ignition--HEI triggered MSD 6-AL; Accel 300+wires
- Transmission--THM 350 with 3.42 gears positraction
(changed from last year's 3.36)
- Hughes 2500 torque converter
- Performance--12.02
with Perfomer RPM/ 12.10 with Torker II (intakes were not on an equal playing field because of
different combination of parts /equipment when runs were made) Spring 1998, 78 degrees, humidity at 89 %, barometric pressure at 30.01---Lee
breaks into the 11s with a time of 11.992 @ 112.75 mph. Update: Best time of 1998: 60' time 1.681 sec; 1/8th mile, 7.52
@ 91.5; 1/4 mile 11.90 @ 113.5 mph
Lee thanks Malrey, Don, and Dwight
at Pyle Bros. rear-end shop (281-421-5878) for the excellent service, help
and advice on rear-ends AND engine building. Also, Bill at Performance
Connection for great deals, service, and quick delivery of parts (1-800-275-7637);
and Mark at Deer Park Muffler who made 3" tail pipe bending look easy.
A very special thanks to fellow Pontiac enthusiast
Skip Fix for being a good source of info, allowing Lee borrow his Performer
RPM intake for performance testing, and flow testing his heads.
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