- Home »
- Catalog »
- Superchargers & Accessories »
- Superchargers- Head Units Only
Superchargers- Head Units Only
Pontiac V8 Superchargers- Head Units Only
Head Unit Only — Superchargers- Head Units Only for Pontiac V8s
Superchargers, head units only is the shelf for the blower itself with no brackets, no pulleys and no plumbing. It exists for two builders: the one adding a Butler ProCharger bracket kit to a head unit he already owns, and the one stepping up from a smaller charger on a bracket that already fits.
Butler stocks the self-contained ProCharger F-series units that our Pontiac brackets are built around, the F-1A, F-1A-91 and F-1A-94, all satin finish, standard rotation, and all rated by ProCharger to 38 psi.
Browse Superchargers- Head Units Only Products
Popular Brands:
More About Superchargers- Head Units Only
1. The Three F-1A Units Side by Side
All three are self-contained and share a 9" volute, a 5.40:1 internal step-up ratio, a 74,000 rpm maximum impeller speed, a 5.56" exducer, a 2.62" volute outlet, a 3" outlet hose and a 4 oz oil capacity. ProCharger lists a typical N/A base engine range of 300 to 500 hp for all three. What separates them is inlet airflow.
| F-1A | 1100 max rated supercharged hp, 1575 CFM maximum flow, 38 psi maximum boost, 3.5" inducer, 3.75" inlet hose. |
| F-1A-91 | 1200 max rated supercharged hp, 1600 CFM, 38 psi, 3.57" inducer, 3.75" inlet hose. The middle step, and it keeps the same inlet size as the F-1A. |
| F-1A-94 | 1300 max rated supercharged hp, 1625 CFM, 38 psi, 3.7" inducer. This one moves to a 4.0" inlet in place of the 3.75" inlet used by the F-1A and smaller blowers, which means a custom inlet is required, and it is roughly .38" longer overall. |
2. Fitting a Head Unit to a Pontiac Bracket
| Bracket compatibility | The Butler Custom Pontiac ProCharger bracket kits are listed as compatible with the P-1SC, P-1SC-1, P-1X, D-1, D-1SC, D-1X, F-1D, F-1A, F-1A91, F-1A94, F-1C, F-1R, F-1X and F-2, so any of these three drops onto the Butler plate. |
| Stepping up from a P-1SC or D-1SC | The F-1A-94 bolts on to the bracket in place of a P-1SC or D-1SC. The gear ratio changes with it: the F-1A-94 runs 5.40/1 where the P-1SC and D-1SC run 4.10/1, so you do not need as small a pulley to make the same boost, and the larger pulley gives better belt wrap. |
| Cog drives need an F-series | The F-series bearings are built to handle the added forces of a cog drive. ProCharger does not recommend a P-1SC or D-1SC with a cog drive. |
3. Size the Bypass Valve or Pay for It
The most expensive mistake on a big head unit is an undersized bypass valve, and ProCharger spells out what it costs.
| What to run | A ProCharger Red Race Bypass Valve is recommended with an F-1A-94 because of the amount of air the blower moves. Past 20 psi, two Red Race Valves are recommended, or one of the larger ProRace bypass valves. |
| What happens if it is too small | Compressor surge, which is very hard on the gearcase of the blower. Slamming the throttle shut with nowhere for the air to go also cracks intercooler welds, leaks hoses and slips blower belts. |
Settle the bracket kit and the compression before you buy the head unit. The blower is easy to change later; the short block under it is not.
Not sure what your Pontiac needs?
Email our tech team at tech@butlerperformance.com. Tell us your engine, heads, car, and power goal, and we will put the parts together as one combination that works.