421 SD 1961-63

Pontiac V8 421 SD 1961-63

Nothing Here Is Generic — 421 SD 1961-63 for Pontiac V8s

The 421 Super Duty of 1961-63 is the rarest cylinder head Pontiac ever put in a car, and nothing about it is shared with a common D-port casting. Butler's listings break the SD heads into two groups: the #306 early 1962 heads and the #127 and #980 heads, each with its own Ferrea intake and exhaust valves.

Butler lists Super Duty specific parts across the catalog, including 1962-63 Super Duty guide plates that fit the #980 and #127 SD heads, and 7/16 rocker stud upgrade kits built for 1961-1966 389-421 heads, alongside cast iron guides, seats, seals, springs and locks.

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More About 421 SD 1961-63

1. Two Different Super Duty Head Groups

Butler's valve listings do not treat the SD heads as one part, and neither should you.

The #306 early 1962 heads	Butler lists a distinct Ferrea stainless intake valve set and exhaust valve set specifically for #306 early 1962 421 SD heads.
The #127 and #980 heads	a separate Ferrea intake set and exhaust set are listed for these castings, at different sizes than the #306 pieces.
Guide plates	Butler carries Fabcraft 1962-63 Pontiac Super Duty guide plates listed as fitting the #980 and #127 SD heads, sold as a set of eight. That is a Super Duty only part.
Read the casting	with values like these, verify the number on the head before any part is ordered or any material is removed.

2. Early Head Rocker Studs

The 421 SD falls inside the early Pontiac stud problem, and the machine work is serious.

Stud conversion	Butler's 7/16 rocker arm stud upgrade and conversion kits for 1961-1966 389-421 heads require that the holes be drilled and heli-coils inserted, and that the stud bosses be milled, work Butler says should be done by a qualified machine shop.
Through-stud oiling	certain pre-1964 heads oiled through the stud. Replacement studs do not have oil-through holes, so on those applications use rocker arms and pushrods with an oil hole.
Material is limited	there is no generic torque spec for these studs because every head is different, and pre-1964 heads can crack once the studs are out. On a Super Duty casting that is not a risk worth taking casually.

3. Everything Else In The Head

Guides	Pontiac cast iron guides in 11/32", cast or bronze, with the machinist confirming the dimensions against the casting on the bench.
Springs	Butler groups Super Duty spring choices with the Edelbrock and Ram Air IV heads rather than with the common cast iron castings, because of the installed height these heads work at.
Pushrods	the 421 shares the shorter pushrod length with the 326 and 389, not the later 350 through 455 group.

Call before you order anything for a Super Duty head. These castings are too scarce to fix a guess on, and Butler would rather confirm the number with you first.

Not sure what your Pontiac needs?

Call our tech team at 866-762-7527. Tell us your engine, heads, car, and power goal, and we will put the parts together as one combination that works.