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Exhaust Manifolds 1964 - 1990

 

Exhaust Manifolds 1964 - 1990

The 1969-72 exhaust manifolds feature a divider between the center exhaust ports. The 1967 and earlier models do not have this feature. Also, all manifolds except 1970 to 1972 will have a heat riser (shutoff) on the left-side exhaust manifold.

All Olds small-blocks with dual exhausts used the single-exhaust right-hand manifold, with one opening capped off. There are no true dual exhaust small block manifolds.

[ Thanks to Kevin Hoopingarner, Bob Barry for this information ]


Identification

The cast-in ID consists of a large [1"] letter or number, usually found at the front, over the front exhaust port. On earlier units, it can be found over the REAR exhaust port. There is also a 6-digit casting ID, usually somewhere near the center.

As per convention, if the big single-character ID is a number rather than a letter, that denotes a small block part. It was not uncommon, especially after 1970, for small block exhaust manifolds, such as 1 and 4 or 5, to be used on big block cars. Sometimes you can find dual exhaust manifolds on big cars, too.

Exhaust manifolds come in many styles, we'll cover the most popular. The main difference for the performance enthusiast is whether the center ports are divided in the manifold, as in the late W and Z units. LH= for left hand side, RH= for right hand side of engine.

D, E, G, H, J, K?- Toronado exhaust manifolds. Duals. They typically turn up and out at the outlet, far more so than those for any other car. Since that would run the exhaust into the frame or body of most cars, these are useful mainly for identifying a Toronado engine.

A number of sources have pointed out that there is no difference between W-30 and 442 exhaust manifolds. An article in JWO explained confirmed this.

NOTE: The W 389268 was not used on the 68 442 as stated in the Supercars book and other places. The 68 uses a unique manifold (Y-398706) with heat shield.

[ Thanks to Chris Witt, Ed Ekstrom, Dan Williams for this information ]


Year         ID/    Casting
Used         Code   Number    Application
'65 - '67      X    389269    LH; Cutlass, 442.
               W    389268    RH; Cutlass, 442.
'67 - '69      A    384785    LH; full size. 425.
               T    39870934  RH; full size. 425.
'68                           Cutlass: early 1968 models use same as 1967.
                              Cutlass: late 1968 models use same as 1969.
'68            T    398708    RH; big block
               X    389269    LH; Cutlass, 442, some VC and SX.
               Y    398706    RH; Cutlass, 442, some VC and SX.
               R              LH; full size.
'68 - '70      S    384895    RH; full size. With heat shield to protect
                              steering box.
'69 - '74      W    402295    LH; Cutlass, 442, W-30, H/O.
'69 - '72      Z    402294    RH; Cutlass, 442, W-30, H/O.
'70 - '??      X    412287    LH: full size, Cutlass.
'73 - '74      X    412287    LH: 442, W-30.

               H    411970    RH; Toro.
               J    407103    LH; Toro.

               1    380001    LH; X-over.
               1    411961    LH; No X-over. Straight down. 350 diesel. Gas also.
               1    411981    LH; 350 gas.
'65            2    380145    LH; 330.
               3    381921    RH; X-over.
               4
'68 - '73      5    398704    RH; X-over. 350. Delta 88.
               8    558319    With "Z-Y" underneath the "8".
               8    558480    With "H-Y" underneath the "8".
'81           14    22503678  LH; 260.
'81           17    2506300   RH; 260.
               3    563619    RH; 350 diesel. Gas also?
[ Thanks to Chris Witt, Kevin Hoopingarner, Mark Prince, Kevin O'Brien, Matt Cremean for this information ]


Detailed Listing

ID Casting # Side
A 384785 LH
Used on big cars about 1967 to 1969. Single outlet is straight down in the center, not good for an A-body car. Companion to T, typically.

H 411970 RH
Toronado.

J 407103 LH
Toronado.

R LH
Used on big cars. ## holes?, exit angle? Might fit in A-bodied cars, with effort. Companion to T, typically.

T 3987094 RH
Used on big cars about '67-'69. Two holes; one for crossover pipe from the LH side. Main outlet has 2-bolt flange angled about 45 degrees down and back. Might fit in A-bodied cars, with effort. Companion to A, typically.

W 389268 RH
1965-67, A-body with big block and dual exhaust. This one has the W over the rear runner. Does NOT have a divider between center ports. One 2.5" outlet, 2-bolt flange, points about straight down. Companion to X-389269-LH. See also Y-389268-RH [?]

W 402295 LH
1969-72 442, W-30, H/O, A-body with big block and dual exhaust. "W" is over the front runner. THE most desirable set to have. Has divider between center ports. One 2.5" outlet, 2-bolt flange, points about straight down. Companion to Z-402294-RH.

X 389269 LH
1965-68 442, A-body, some Vista Cruiser and SX's with big block and dual exhaust. This one has the W over the *rear* runner. Does NOT have a divider between center ports. One 2.5" outlet, 2-bolt flange, points about straight down. Companion to W-389268-RH.

X 412287 LH
1970-up? A-, B-, C-body with big block and dual exhaust. Has the divider between center ports. One 2.5" outlet, 2-bolt flange, points about straight down. Good substitute for W-402295-LH.

X 412287 LH
1973-74 442, W-30 with big block and dual exhaust. Has the divider between center ports. One 2.5" outlet, 2-bolt flange, points about straight down. Good substitute for W-402295-LH.

Y 398706 RH
1968 442's, A-body, some Vista Cruiser and SX's with big block and dual exhaust. This one has the Y over the front runner. Does NOT have a divider between center ports. One 2.5" outlet, 2-bolt flange, points about straight down. The manifold has raised ridges in it and a heat sheild that rests on them. Companion to X-389269-LH.

Z 402294 RH
1969-74 442, W-30, H/O, A-body with big block and dual exhaust. THE most desirable set to have. Has divider between center ports. One 2.5" outlet, 2-bolt flange, points about straight down. Companion to LH unit W-402295 LH.

1 411961
Small block. ?? about divider. ?? about outlet size, 2-bolt flange, points about straight down. Companion to ?? unit 4-?????? unit.

4
Small block. ?? about divider. ?? about outlet size, 2-bolt flange, points about straight down. Companion to ?? unit 1-411961.

14 22503678 LH
1981 260 small block with single exhaust. ?? about divider. ?? about outlet size, 3-bolt flange, points about straight down. Companion to RH unit 17-2506300.

17 2506300 RH
1981 260 small block with single exhaust. ?? about divider. ?? about outlet size, 3-bolt flange, points about straight down. Companion to LH unit 14-22503678.


Typical exhaust manifold pairs, left/right, are: X/W, X/Y, W/Z, A/T, R/T, R/S, D/E, G/H, J/K, 1/4, 1/5, 14/17

[ Thanks to Chris Witt, Ed Ekstrom, Dan Williams, Mark Prince for this information ]
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