Consider removing the fuel injectors and having them professionally cleaned on a flow bench. Also, use the CRC mass air flow sensor cleaner, and do a good job of removing the carbon from the throttle body and IAC motor with a throttle body solvent. Freshen up the ignition with new Delco parts and consider a swap to a higher numerical rearend gear ratio to use the power the engine is already producing.
None of this is likely the advice you had hoped for. Anyone with the years of experience in this business that I have will tell you that you do not modify your daily driver extensively, especially a high-mileage one. Instead of trying to make your Firebird much more powerful, shift your focus to see how many miles you can get on it with mild mods and without any major repairs. That will provide more "bragging rights" than picking up 50 hp. It will also be a good statement for Pontiac about how good the company's cars are.
Subframe Connectors For First-Gen Ragtops
I have a '67 Firebird convertible, and it is a very solid car with original floorpans and frame-rails. I'm installing a 455 with 425 hp, and I have a Turbo 400 trans. Is twisting the body something I need to be concerned with? I have found frame ties for hardtops, but not for convertibles. Why won't the frame ties fit convertibles? What would be involved with making them fit?
Robert Walsh
Joliet, IL
Rocky Rotella responds:We, too, have a '67 Firebird convertible, and it just so happens to have a mildly built 455 that's backed by a Turbo 400! Unless you have excellent traction, I don't foresee the 455 excessively twisting your Firebird's body to the point of major distortion. I do, however, feel that it is worthwhile to upgrade your Firebird's chassis. That, in turn, will significantly improve its body rigidity-and, in my opinion, subframe connectors are a major piece of that puzzle.
Subframe connectors are available in two common varieties-bolt-on and weld-in. By design, the weld-in type should offer maximum benefit, as it solidly links the front and rear framerails, integrating the entire body. They are, however, practically permanent. Bolt-on connectors can significantly improve body rigidity, too, but are easily removed if so desired. I personally prefer the bolt-in design for their less-permanent installation, and decided to go that route with our Firebird.
At the time, there were no companies producing bolt-in subframe connectors designed specifically for First-Gen Firebird convertibles. Familiar with the typical advantages, we chose to modify a pair of hardtop units to fit our Firebird's convertible-specific floorpan, and the installation was documented in HPP (Nov. '04). The story includes detailed pictures of the process, the unique underbody bracing that requires specific connectors, and the modifications to the particular units we used. If you don't have that issue handy, it's also available on HPP's Web site at www.highperformancepontiac.com.
I've learned that within the past couple of years, a few companies have begun marketing bolt-on subframe connectors for First-Gen Firebirds, and those include Detroit Speed & Engineering (www.detroitspeed.com), and Global West (www.globalwest.net). I don't, however, have any experience with them, so I can't comment on their fitment or design. While installing the subframe connectors of your choice, I'd also suggest new body bushings (either rubber or urethane) to replace the existing units that are certainly aged and/or worn.
We've recently upgraded our Firebird's suspension, further improving its body rigidity and ride and handling qualities-and I think it's something that'll be of significant interest to you. Every modification to our Firebird's suspension thus far has been considered for its advantages balanced with attempting to maintain a stock appearance. It wasn't until we combined the subframe connectors with a plethora of components from Performance Suspension Technology that our Firebird's handling came into its own.