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Cast Iron Heads- 421 SD, Ram Air V
Pontiac V8 Cast Iron Heads- 421 SD, Ram Air V
Three Castings, Three Valve Sets — Cast Iron Heads- 421 SD, Ram Air V for Pontiac V8s
The 421 Super Duty and Ram Air V cast iron heads are their own world. They do not share valve sizes, lengths or in the Ram Air V case even stem diameter with an ordinary Pontiac head, so a standard Ferrea set will not go in them. Getting these castings right means ordering by the casting number, not by displacement.
Butler stocks Ferrea high performance stainless intake and exhaust valve sets cut specifically for the #306 early 1962 421 SD heads, the #127 and #980 421 SD heads, and the Ram Air V heads, plus the Butler Head Builder Kit for rebuilding your own cast iron castings.
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More About Cast Iron Heads- 421 SD, Ram Air V
1. Order by the Casting Number
There is no universal valve here. Each casting family has its own intake and exhaust part number.
| #306 early 1962 421 Super Duty | the exhaust is a 1.660" x 5.350" at 45 degrees and the intake is a 1.920" x 5.350" at 45 degrees, both sold as sets of eight. |
| #127 and #980 421 Super Duty | the exhaust is 1.760" x 5.300" and the intake is 2.020" x 5.300", again at 45 degrees and sold in sets of eight. |
| Ram Air V | the exhaust is 1.730" x 5.400" and the intake is 2.190" x 5.421", both at 45 degrees. |
| Read the casting first | the two Super Duty families are only .050" apart in overall length and differ in head diameter. Guessing between them costs a set of valves. |
2. The Ram Air V Stem and Tip
This is the detail that makes Ram Air V a different build from the moment you open the box.
| 3/8" stem | the Ram Air V valves use a 3/8" stem, not the 11/32" stem that most of Butler's Pontiac valve and seal stock is built around. |
| .225" tip | both the Ram Air V intake and exhaust are specified with a .225" tip. |
| What that changes | stem seals, guides, locks and retainers all have to suit a 3/8" stem. Do not order 11/32" parts alongside these valves. |
| Distributor gear too | Ram Air V and 455 SD cams use a smaller cam gear, so they need the BOP composite distributor gear made specifically for them. It is a related trap on the same engines. |
3. The Head Builder Kit
If you have good castings and are not sure what the rest of the parts list looks like, Butler will build it for you.
| What it is | the cast iron Head Builder Kit is ordered against your own castings. You choose the casting and Butler picks the parts to rebuild the heads correctly. |
| What it includes | Ferrea stainless intake and exhaust valves at stock install height, matching Crower, Edelbrock, DHP or Comp springs matched specifically to your cam specs, chromoly retainers and locks, valve stem seals for machined valve guides, and a shim kit. |
| Why it works | the springs are matched to your cam rather than to a generic list, and the seals assume the guides have been machined, which is what a proper head rebuild involves anyway. |
Butler also stocks Fabcraft guide plates cut for the #980 and #127 Super Duty heads, so the pushrod side of these castings is covered too. Have the casting number in hand when you call.
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.