Third-Gen Camaro owners love their TPI 350s and 305s. The intake runner tubes have lots of eyeball appeal plus they work really well. The wish of TPI owners is that they could pop on a set of inexpensive Vortec heads for a power boost. But alas, Vortec heads will not simply bolt onto the TPI...until now.
Nicky Fowler and his staff at Scoggin-Dickey in Lubbock, Texas, put on their thinking caps and machined a new and unique intake manifold to mate the Vortec heads to the tuned-port 350. You have to wonder how a dealership got into parts manufacturing. During our visit to Scoggin-Dickey we saw some 25-plus people in their parts department answering calls from people all over the United States and abroad. While we were taking pictures of the parts and pieces in this high-tech building, a lady appeared to retrieve Nicky's signature on a large order routed to Argentina. In the course of our day at SDPC, we had occasion to walk through the warehouse. Two men were emptying a pallet stacked about five-feet high with row after row of boxes. Nicky piped up, "We just received this shipment of the Vortec/TPI intakes today."
There must have been a hundred boxes on the large pallet, giving us an idea of the popularity of this new part. You can imagine why. When the Vortec heads were released in '96 (onL31-equipped pickups), it didn't take a brain surgeon to figure out they were an easy 25-30hp bolt-on.
As Nicky told us, "The ports and the combustion chamber designs were vastly improved over the conventional Chevrolet small-block head that came on the previous production years of cars and trucks. Everyone wanted to install them because at that point in time you could buy a pair of cast-iron Vortec cylinder heads for around $360, brand new and fully assembled."
But, alas, for poor 1985-92 tuned-port people, these heads proved incompatible with the stock TPI intake. Six years elapsed. Finally, Fowler, who hob-nobs with GM engineers and high-performance parts experts on his many forays into the Motor City, decided to answer the calls, literally.
He explained, "People were trying to install the Vortec heads on their stock tuned-port intake, and then they'd call us and go, 'Hey, my intake manifold won't work!'" Customers re-drilled the Vortec heads for the conventional small-block Chevy intake bolt pattern and ran into trouble when they tried to bolt on their factory GM TPI intake. As we have shown in the pictures, the intake ports do not match. These early TPI/Vortec cylinder head customers had no options.
Nicky pointed to a Vortec head on a rotating stand. For illustration only, he had overlaid the intake ports with a stock gasket from a conventional small-block Chevy to physically see the raised port of the Vortec head. Nicky stuck his ballpoint pen in the opening between the gasket and the top of the port opening in the head and said. "Here's what happens if you try to bolt your factory TPI intake to a set of cast-iron Vortec heads that you have drilled and modified for the stock intake bolt pattern. Notice the intake manifold will not cover the top of the intake ports."
He also pointed out that if you tried to adjust the manifold upward to cover the top of the Vortec intake port, the contact surface would be so minimal that it would never seal and now the floor of the port would present a sealing problem. It was a total mismatch!
Tuned-port people in the middle of Vortec head swaps were in a pickle. They had to take their intake to a special shop to weld extra aluminum and then mill the surface flat. The costs, not to mention a host of other "quirks" of compatibility we'll show you, defeated their purpose of inexpensive heads, . SDPC cured these problems with their new intake manifold and installation kit.
Ultimately, all this is in the name of power, and boy do the SDPC Vortec TPI base and heads deliver. Using a DTS water brake engine dyno, the Vortec TPI conversion twisted the needle to 305.6 hp, and that was using the stock runners, stock throttle body, a stock L98 cam, 92 octane pump gas, and 15 degrees of base timing. Calculating a 20 percent driveline loss for a 700-R4 transmission, power at the rear wheels is estimated at 244.4 hp. Next up was a combo which added an LT4 Hot Cam, 1.6 ratio roller rockers, a 52mm throttle body, and Edelbrock High Flow runners. Power swelled to 356.7 hp at a very streetable 4,900 rpm. With a conservative 20 percent driveline loss, that would come out to around 285.3 rearwheel horsepower. Now that's what we call affordable bolt-on power!