1. Engine and Transmission Selection:
* Engine: Choose your Chevy small-block (e.g., 350, 305). Consider the condition, power goals, and budget. A crate engine simplifies the process significantly.
* Transmission: You'll need a transmission compatible with the Chevy small-block. Common choices include TH350, TH400 (automatic), or a T5, Tremec TKO, or Muncie (manual). You'll likely need an adapter plate for the bellhousing to match the transmission to the engine.
2. Engine Mounts:
* Fabrication: This is the most crucial and challenging part. The Lemans's frame doesn't have mounting points for a Chevy small-block. You'll need to fabricate custom motor mounts. This often involves welding, modifying existing parts, or using aftermarket mounts designed for this specific swap (if available). This may require significant expertise in welding and metal fabrication.
3. Transmission Mount:
* Fabrication or Adaptation: Similar to the engine mounts, you'll likely need a custom or adapted transmission mount.
4. Drive Shaft:
* Custom Drive Shaft: The Chevy small-block and transmission likely won't align with the existing Pontiac driveshaft. You'll need a custom-length driveshaft made.
5. Exhaust System:
* Custom Exhaust: The existing exhaust system won't fit. You'll need a custom exhaust system fabricated, likely including headers designed for a Chevy small-block in a Pontiac engine bay.
6. Wiring:
* Wiring Harness: The Chevy engine's wiring harness won't be compatible with the Lemans's system. You'll need to adapt the wiring or utilize a universal wiring harness designed for this type of swap. This often involves splicing and careful attention to detail.
7. Cooling System:
* Radiator: You might need a different radiator, potentially a larger capacity one to handle the Chevy small-block's heat output. The existing hoses won't fit.
8. Fuel System:
* Fuel Lines and Pump: You may need to adapt or replace the fuel lines and pump to accommodate the Chevy engine's requirements.
9. Other Considerations:
* Steering: The engine may interfere with the steering components. Adjustments or modifications may be needed.
* Brakes: Depending on the power of the Chevy small-block, you may want to upgrade the braking system for improved stopping power.
* Body Modifications: You may need to trim or modify parts of the Lemans's body to accommodate the Chevy engine and transmission.
Resources:
* Online Forums: Search forums dedicated to Pontiac and engine swaps. There are likely others who have done this swap, and you can learn from their experiences and potential challenges.
* Professional Shops: Consider seeking the assistance of a professional mechanic or custom fabrication shop experienced with engine swaps. This is a complex project and can be significantly more challenging for a novice mechanic.
In short: This is not a project for beginners. It requires significant mechanical skills, fabrication expertise, and specialized tools. If you lack experience, it's strongly recommended to seek professional help. The cost and time involved can be substantial.
