After picking up 53 rear-wheel horsepower and 30 lb-ft of torque with a Crane cam and Airflow Research 195cc cylinder head swap on our 383-powered Corvette project car (Super Chevy, November ’13), we were driving on Cloud Nine. These upgrades were a huge improvement on the street, but we had a feeling the little 383 had more to offer.
We were speaking with Tony Mamo from AFR during the head test, and he told us that although we had been using a very good dual-plane intake (Weiand Stealth), he was confident his company’s TX-series single plane manifold would be a perfect addition for our street-only application. We decided to call his bluff, so to speak, and did a full test on AFR’s new Titan polymer intake line to see just how well these single planes stacked up against our dual plane.
The Titan TX-series uses a polymer base, with your choice of single-plane uppers—a taller race version (TXR) or lower street application (TXS). The uppers can be swapped without unbolting the base from the heads, making for a quick, neat changeover. The other plus is the composite upper/lower combo weighed in at only 7 lbs—half the weight of our current intake. And after multiple dyno pulls the intake was much cooler than its aluminum counterpart.
Back when we did the head and cam swap, we noticed that the shaft in our factory tach-drive distributor was getting rather wobbly. It could be wiggled a good eighth of an inch back and forth. This was evident in the street drivability, where the engine idle speed would hunt, and there would be occasional run-on when we switched off the ignition.
Another issue, which had been present since we bought the car, was the drive gear for the factory mechanical tach was chewed up. One of the car’s previous owners epoxied over it and we were forced to use an aftermarket electric tachometer rather than the factory piece. The new MSD Pro Billet tach drive distributor and matching 6AL digital ignition controller would hopefully cure both of these ailments.
To make sure the car was running to the best of its ability, we swapped in the new distributor and controller first, established a new baseline, then tried out the manifolds. Read on!