THE BEST WHAT WHY
AFTERMARKET CAMSHAFT JM-20-22 with automatic trans More lift with less duration
(266/274deg advertised duration, delivers superior driveability
0.496/0.512 inch lift, 112deg lobe and more performance over the
centers); JM-22-25-10 with manual now-obsolete factory W-series
trans (274/280deg advertised grinds
duration, 0.512/0.523 inch lift,
110deg lobe centers)
AFTERMARKET HEADERS Hooker Headers Hooker is redesigning its 1 3/4
inch and smaller collector
flange openings to equal the
big block Olds' port exit size
(larger flanges are already the
right size)
AFTERMARKET INTAKE MANIFOLD Edelbrock Performer 455 Olds Good through 6000 rpm; no
Performer RPM is available
for the big-block Olds
BLOCK '67-'71 425/455 (ident. F,F1,F2,F3 Thicker cylinder walls permit
or F4) 0.100-0.110 inch overbore (up
to .0125 with sonic check)
other blocks can only go 0.060
CARBURETOR Reworked stock Q-jet, Edelbrock Q-jet is hard to beat for
850cfm or Holley 0-4781 850cfm street economy, but Holley
double-pumper (manual trans), or delivers more top-end power
0-3418 855cfm vacuum secondary
(auto trans)
CONNECTING ROD Any big-block Olds rod All big-block rods are forged
and can do the job if
properly prepped and fitted
with ARP bolts
CRANKSHAFT '68 Toronado 455 forged steel Virtually unbreakable, but
rare; high nodular iron cranks
(look for large "N" on #1
counterweight) are a good
second choice
CYLINDER HEAD '65-'69 400/425/455 (ident.A,B orC) A,B or C heads treated only to
a 3-angle valve job will
outflow later street/strip
ported G,J or K heads; however
hardened exhaust valve seat
inserts for unleaded gas
compatibility must be added
FACTORY CAMSHAFT W31 with automatic trans (308deg Best street cams in their day
advertised duration, 0.472 inch but now obsolete
lift); W30 with manual trans (328deg
advertised duration, 0.472" lift)
FACTORY EXHAUST MANIFOLD '68-'76 442/W30, '69-'71 455 Has full divider between
station wagon (ident. W,X,Y or Z center exhaust ports, is
near head pipe connection) smoothly swept back to rear
FACTORY INTAKE MANIFOLD Any non-EGR iron or aluminum EGR intakes are more
4-barrel intake restrictive. All pre-EGR
intakes flow about the same.
The '70 aluminum W30 intake is
a duplicate of the '70 iron
IGNITION SYSTEM Resurved HEI triggered by MSD-6 As reliable as you can get
OIL PAN Toronado Holds 5 quarts (6 with filter)
1 more quart than other
stock pans & Fits most chassis
PISTON TRW L2323F or Speed-Pro 2278P Can machine dish to yield a
variety of compression ratios