August 2012 Chevy High Performance Q&A

Kevin McClelland Jun 27, 2012 0 Comment(s)
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The Natives are Restless

I got several letters this month about one of my answers in the March issue. I have not gotten such pointed criticism since I once said that 307 small-blocks were not performance engines! I got letters for months about that because many people had built strong-running 307s and I must have been out of my mind. Well, if those folks would have gone back and read everything I said about 307s, they may have been a little more understanding of my comments.

1208chp 01 O  August 2012 Chevy High Performance Qa Editor 2/3

This brings me to my latest flirtation with disaster. First of all, I did make a mistake when I said, “There isn’t a TBI manifold on the market that offers the Vortec cylinder head bolt pattern.” Well, this error was quickly brought to my attention by Dr. Jamie Meyer and his staff at Chevrolet Performance, which, in fact, does offer a manifold under PN 12496821. This is a replacement high-performance dual-plane manifold that will bolt right up. This was an oversight on my part, and I’m glad you guys contacted us to get the message back out there about your manifold. Thanks.

Another letter writer felt I blew off the reader with a canned answer from one of our advertisers. This is the farthest from the truth. I recommend component parts packages from manufacturers all the time, but I do so because they have done all the engineering to make swaps and performance gains painless.

His main rub was that I didn’t answer the reader’s original question, which was how to install a 400 small-block under this 2 BBL throttle-body injection. He pointed out various ways the reader who wanted to increase his displacement could have done so with help from other aftermarket suppliers. This would have required the reader with the El Cam to have extensive tuning experience and purchase software to calibrate his TBI to work with the larger-displacement engine. I also hadn’t recommended a camshaft to work in this application with the throttle body. All valid points.

The bottom line is I feel it’s my responsibility with this column to help as many people as I can with my answers. If there are 5 percent of readers out there who could have done all the work and tuning on this package without a problem, that’s great. I have extensive experience trying to build high-performance TBI engines and tuning and have never been satisfied with the performance and driveability with high-performance TBI systems. They have inherent fuel-steer issues because of the throttle-body design that causes fuel distribution problems at various engine speeds. Also, when you try to make real power with a TBI, the injectors get too large and you have idle stability problems. This is not to say that TBI injection systems don’t work very well in stock applications.

I want to make sure what I write about is doable for most of my readers. If you readers out there feel you have the skill set to take it to the next level, please do. That’s how most of us have gotten there in the past.

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