STAGE 1 CONVERSIONS
Buick made Stage 1 cylinder heads from the same castings as the standard 455 head, they added a few machining processes to the standard 455 casting and created the Stage1 head.
Stage1 cylinder heads differ from standard Buick 455 heads in the following area's:
 | STAGE 1 HEADS | STANDARD 455 HEADS |
| Intake valve dia. | 2.125" | 2.00" |
Exhaust valve dia.
Valve stem dia. | 1.75"
3/8" | 1.625"
3/8" |
| Combustion chambers | Unshrouded with machining process | As cast |
| Bowl area | Machined for larger valve | - |
| Casting | same as Std 455 head (year specific) | (year specific) |
In addition to our rebuilding of the heads, every Stage1 conversion that GHP does contains:
- Unshrouded combustion chambers
- Profiled intake and exhaust port bowls (throat area)
These two procedures are often overlooked and negate the performance increase available with correctly built Stage1 heads.
Note: GHP Stage1 Conversion heads are fully rebuilt with quality parts such as New Stainless Steel Swirl Polished Valves, Bronze valve guide liners that are honed to final size, new valve locks and quality Viton valve seals. We will not offer lower quality parts and machining processes to compete with other machine shops. Quality parts, Quality machining and assembly for a fair price.
Stage 1 and standard small valve 455 heads both utilize the same casting number.
Combustion chamber around intake valve being unshrouded.
Stage1 conversion showing unshrouded chamber and machined throat area. |