I stopped down at Troy's today after work today because I had a couple of questions for him. I wanted to get his opinion on using a newer ECM along with the Painless EFI harness. In order to make the new harness work, I will need to use an ECM out of an 1986 to 1993 Firebird. I was a little concerned about being able to balance and tune the Cross-fire with a newer ECM. Troy said that it would not be an issue.
The second thing I wanted to ask him about was the intake manifold. I am trying to decide whether to leave it stock, port it out, or purchase the Renegade manifold. Troy said I would definitely see a benefit by porting the manifold and even more by using the Renegade manifold. He was trying to explain just how restrictive the stock manifold was. He said it might be easier to just show me... also, they just finished painting the engine red! We went to the back of the shop to check it out.
Here is the engine:
Check out these roller rockers:
Here are the intake ports on the engine block.
Here they are on the opposite side. Notice how close the gasket holes fit the port openings (keep in mind it is a little off-center in this picture). The gaskets are die cut to fit the ports exactly.
Here is the gasket on the bottom of the stock manifold. Look how restricted the ports are.
Here is another picture showing how much smaller the ports are on the intake manifold.
When I saw this, it became apparent to me that I really need to either port the stock manifold or purchase the Renegade manifold.
When I think about the time and effort that would go into porting the stock manifold (not to mention how easy it would be to screw up) it just makes more sense to purchase the Renegade manifold. I could achieve some of the benefits by porting, but not all. The Renegade manifold was designed from the ground up to make maximum use of the stock shape and dimensions. I have decided to order one. When it arrives I will do a side-by-side comparison of the manifolds to highlight the differences.