by Bill Boyle
|Enthusiasts with '77-79 Trans Ams and Formulas powered by the 400 (TA 6.6 engine) who must comply with emissions testing in their locale have only one aftermarket intake option available to them today. It's the Edelbrock Performer EGR, part number 3756.
For those who aren't familiar with the stock OEM intake unit for the 77-79 Trans Ams and Formulas, it is cast iron and designed to work with exhaust gas recirculation (EGR). One of these OEM units is easy to spot without the carb as the large secondary openings are not round but d-shaped. With the carb in place it can be spotted by looking for the little bumps or dimples located over the rear runners. The secondaries at first glance, appear to be restrictive in nature, yet in class drag racing the "dimpled " smog intakes are used quite successfully. For those who wish to dare, as I did, here's what I discovered when I made the after market swap to the Edelbrock Performer intake with EGR.
|Having plenty of time to exam the EGR Performer, I discovered several things that made me wonder about making the swap. First of all, I noted the size of the runner ports. They were much smaller in size than those of the stock unit. Using a Fel-Pro 1233 intake gasket as a template, I could easily see the lack of uniformity in size of the ports. Thirdly, as I discovered, this swap was not a simple bolt on right-out-of-the-box. My thoughts focused on, should I bolt it on "as is" or should I clean up the ports?
What to do? Well, being an avid car guy, I decided to measure the runner ports with a dial caliper. After taking careful measurements, I found the largest runner port and proceeded to grind on all the others to get the same dimension--length and width. I didn't port match to a gasket...just enlarged the opening a few thousandths so all were the same size. This took a couple of hours of careful grinding with a Dremel and measuring with dial calipers. The intake was vacuumed to remove all aluminum grindings.
As to the EGR, the original unit was removed from the OEM intake which was still on the engine. To make it fit correctly necessitated using the Dremel again. After an hour of carefully grinding and trial fittings, the EGR finally fit flush against the side of the plenum. Again, the intake was vacuumed of all grindngs.
Thereafter, I removed all the other OEM fittings and TVS from the stock unit and transplated them to the Performer. After siphoning all the collant from the radiator (less mess using a siphon) into a large bucket for reuse, the fuel line was disconnected at the carb. Next I detached the accelerator cable and all vacuum hoses carefully noting where they go. All emission fittings swapped out fine. The alternator was disconnected to access the front intake-casing bolt. With all coolant out of the top of the head I removed all the intake bolts and removed the heavy 45 pound unit from the engine.
Paper towels were used to fill the intake openings on the head so that gasket particles would not find their way into the combustion chambers. As the old gasket was relatively new, most of it came off in large pieces. A new 1233 Fel-Pro gasket would be used on the swap to avoid any possible leakage. The gasket was installed on the heads using a few dabs of gasket sealer to hold it in place. With all gasket particles removed with my shop vacuum, all paper towels were pulled from the ports and the new lighter weight 17-pound Performer was positioned and secured to the heads. With rubber seal in place, the front intake-case bolt was started first. Each new bolt was properly torqued and retorqued to prevent coolant leakage. My old reliable 160 degree thermostat was swapped, however, I opted for a chrome water neck replacing the cast aluminum one. The EGR was installed followed by the q-jet. Everything was tightened down and the fuel line re-connected. The accelerator bracket, cable, clip and returns springs were reinstalled.
|The arrow points to the area marked that was contoured by grinding so the EGR would seat against the plenum.|
|After refilling the radiator (again using the siphon--from the bucket to the radiator) I checked for coolant leaks. There was seepage from the drivers side inlet. So the bolts were tightened a little further. Finally, it came time to install the base of the air cleaner....To my surprise the air cleaner would not seat on the carb. The base was prevented from seating because the stock accelerator bracket was now higher than it was when mounted on the stock unit.
Frustrated, I went to plan B and got my scrap aluminum to fabricate a new bracket. [Whether Edelbrock makes and sells a bracket that will work was not looked into.] Within 3 hours a new bracket was designed from card board, transformed to the aluminum and a new bracket was fabricated, polished and bolted in place. It did the job nicely. With the K & N air cleaner and lid secured, the shaker bonnet was installed.
When I lowered the hood I was met with another surpise. What I saw was something totally unexpected. The shaker did not fit squarely through the hood and sat closer toward the passenger side of the car than before. In addition, the shaker sat further back in the hood opening compared to the stock position. It was very noticeable to me. This was rather disappointing as I presumed it would be identical to the stock location.
It's been a month since making the swap (late Feb 2002) and I've put some miles on the car. Acceleration seems to be good but since I've not tested at the strip, the performance aspect of the Performer EGR is still unknown. With all the grinding and need to fabricate an accelerator bracket, swapping out the old cast iron unit with the Performer EGR was certainly not a simple out-of-the-box bolt on.
Two final observations: this is first intake swap that I've performed where I couldn't immediately feel more power through the seat of my pants. Secondly, despite using the 1233 Fel-Pro gasket with sealer around the water crossover inlets, coolant continues to seep from the driver's side inlet. This problem I've not encountered with any OEM or after market intake before. It makes me wonder, is the dimpled smogger intake superior to the Performer EGR?