The engine formerly installed in bowtie6 was a 60 degree 3.4 litre V6 as originally fitted to 1994 GM F-bodies (Camaro/Firebird). The engine was in its stock configuration to begin with, however during the 4 years I’ve had it installed I’ve done a number of “improvements”.
I’ll start by describing the unusual intake manifold. The original manifold on the stock 3.4 V6 is very restrictive. The throttle body and runners are very small. My cousin Jim Thompson is a professional machinist and he can do wonders with a milling machine, lathe and a welder. So we decided to do a little experiment…
First, we cut off the nose of the original stock intake manifold. Then, the manifold was chucked on a Bridgeport milling machine and a few passes with a large endmill were made. This exposed the intake runners and we were finally able to see just how small and restrictive they are. So, the runners were further machined and cleaned up.
Basically what we ended up with was the bottom half of the stock intake manifold. Pieces of aluminium sheet stock were cut and carefully tacked to the bottom half of the intake manifold. Soon, a more even and much larger upper plenum was formed. Seams were welded up and some trick work was done with a file to shape the edges and make it all look seamless. I think the end result turned out really nice.
Then we replaced the small throttle body with one from the legendary LT1 V8. The LT1 throttle uses twin buttlerflies and thus can keep up with the extra volume of the new intake. Fortunately, the LT1 throttle body also uses the same type of throttle position sensor and idle air motor as the V6 does, so the ECM recognized all this without throwing codes. The intake is also made in such a way that the MAP sensor still mounts to its original location and is connected to the intake via a small rubber hose. Finally all vacuum lines are located in their factory locations.
The intake was then cleaned very carefully and several coats of high-temp silver paint were applied. While tacky, I sprayed several coats of high-temp clear. The end result functions as good as it looks.
So why go through all this trouble?
- We wanted to experiment what would happen with a bigger intake and throttle body.
- The engine needed the extra air volume. This engine is running larger injectors, a hot cam, 1.6 roller rockers, headers and fully ported and polished heads.
- Last but not least, because we can do it.
The end result is pretty impressive: Throttle response is amazingly quick. With the collection of engine modifications, the engine does not run out of breath as much as it used to. Also, the engine revs in a much smoother way with a higher redline. One could argue that some lower end performance was sacrificed for a much nicer middle and upper range. Sure. But when this engine pulls a 2200lb car (instead of 3500 as in the F-Body) that is a very acceptable trade off.