The 'Number=SB, Letter=BB' coding extends to intakes, too. Usually,
the big ID [not the 6-digit ¼" tall all-number ID] letter or number
will be found near the front, often down in between the front fuel/air
runner and the front water passage which contains the thermostat.
The cast-in ID consists of a letter or number, usually found in the depression
just behind the thermostat's front right water passage and the #8 cylinder's
runner. It is a 6 to 8 digit number, usually
on one of the intake runners, often behind the carb, and usually near a
raised CFD and star (dot with radiating lines). Not to be confused
with the 8-digit firing order, which is always 18436572.
These intakes seal directly to the block. They are not raised, using
a seperate valley cover (not to be confused with valley tray). Typical thermostat
housing front and center. This uses the distinctive gasket with one large
hole (for the t'stat), two opposed bolt holes on either side, and the bypass
hose hole in the front.
1965 was the only year for the square bore (i.e. non-Q-Jet) intake
manifold for the 400/425 big blocks. In theory this would fit any
square bore carb.
A solution to run a square bore Holley on this manifold was to use
an adapter plate which
can be found for about 25-30 bucks in most speed shops. It does exactly
the job you're looking for, but get a few extra gaskets just in case
this more-complex-than-stock setup generates vacuum leaks.
Note: that the t'stat on the 1966 L-69 3x2 Tri-power manifold is
further forward than on other Olds V-8s, due to the need to clear the front
carb, and thus uses a unique molded bypass hose for this application.
It also uses a pair of roughly square covers, one on either side of
the center carb, bolted to the top of the exhaust crossover
passageway. Each cap should have four bolt holes, but only
be held on with two bolts. These are the exhaust crossover
blockoffs on the 1966 manifold.
Pre-smog intakes are said to flow about the same. Easy to spot - no EGR
valve or place to attach one means it is a pre-smogger intake!
Note that Toronado units
had very low rise intakes. This might be an advantage if hood clearance
is more important than all-out power generation.
Generally speaking, in the pre-71 era, 2-barrel engines were 'low compression'
[9.0:1] and the 4V engines were high compression [about 10.2:1].
Toronado's from 1966 to 1970 had the very low intakes. I know of
no substitute which allows for a stock hood height.
The 1968-9 "J" 4V intakes used a carb whose choke coil was
'divorced' or mounted in a cavity in the intake, rather than the round black
choke coil mounted on the carb as later applications used. A divorced choke
is a recess in the intake on the passenger side of the intake. This choke has
a sort of squarely bent metal covering. This remote
choke coil is VERY expensive, about $75, so unless you need it for originality
or can work your choke some other way [later model, hand, electric...]
you might want to avoid USING that manifold. It still makes a nice way
to identify a 1968 to 1969 Olds engine. As long as its choke coil
still works, no problem.
[ Thanks to Chris Witt, Joe Padavano, Chris Fair, Bill Culp, Mark Prince
for this information ]
Intake manifolds are cast iron unless otherwise noted.
Code Number Year(s) Application/Notes
B 384439 '65 400 All 4V. Square-bore carb mount. Iron.
E 390390 '66-'67 400/455 Including 4V W-30. Early 400, other BB's
except Toro up to 68 or 69 or so. Iron.
F 393238 '66 400 L-69 3 x 2. Easy to spot by the 3 carb holes.
A pair of roughly square covers, one on either side
of the center carb, bolted to the top of the exhaust
crossover passageway. Each cap should have four bolt
holes but only be held on with two bolts. These are
the exhaust crossover blockoffs. Iron.
G 397357 '67 425
J 398662 '68-'69 400/455 Except Toro, incl. W-30 and 68 H/O. Iron.
K 398664 '68-'69? 455 Toro.
? 405233 '69 455 H/O. Very rare, obviously. Only 1 application. Iron.
? 406115 '70 455 W-30. "Oldsmobile W-455" in raised letters.
Aluminum. "Olds W-455" on some.
L 404521 '70-'72 455 4V AT and MT. 442, SX, 88, 98's. Except W-30. Iron.
R 407567 '70-'72 455 4V MT except W-30. No EGR. Iron.
A 407570 '71-'72 455 W-30. "Olds W-455" cast in raised letters. No EGR. Aluminum.
U 410448 '72 455 4V MT except W-30, alternate to R for '72. Iron.
H 388625 2V. Iron. EGR.
X 412493 '73-'76 455 Toro. Iron. EGR. "OLDSMOBILE" cast in.
? 412753 '74 455 4bbl L-74, L-75. EGR. Iron.
Y 411990 ?? ??. EGR.
Y 413111 '73-'76 455 All models, GMC motorhome. Iron.
? 381920 '65 330 1V. Iron.
1 407571 '70 350 W-31. Aluminum.
8 '65 330 2V. Iron.
13 410670 2V. Iron.
16 411880 '74-'77 350 all 4V. 88's. Iron. EGR. Raised letters
"OLDSMOBILE" (5/8") on runner
1606818 '75-'79 350 2V port injected EFI. Aluminum. EGR.
17 22503087 4V. Iron. EGR.
for #1 and #4 cylinders. '77 has no letters. Iron. EGR.
A1 2V. Aluminum. EGR.
A2 NONE '81 260. Aluminum. EGR.
A4 4V. Aluminum. EGR.
A5 4V. Aluminum. EGR.
22500203 Diesel. Iron. No EGR. Machined 3 1/3" opening
at the front for the injector pump.
EA18743 '69 Experimental W-30. 4V. Aluminum. Divorced choke.
3ER-38086 Experimental 350 CFI (central fuel injection). 2V.
Aluminum. EGR. 3 bolt holes at base for injection unit.
2 bolt hole towers toward rear of manifold.
[ Thanks to Chris Witt, Ed Ekstrom, Joe Padavano, Rich Scott,
Kevin Hoopingarner, Graham Stewart, Mark Prince, Jim Chermack,
Kevin O'Brien, Greg Pruett for this information ]