First Run!

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I retained the stock LT-1 accessories by using a short 1991 Corvette crank pulley, but it still wasnt short enough, so I had to space the accessory bracket off the block by 1 inch. these 2 bolts and one washer gave me the space exactly.

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Notice the 3/4" plumbing coming out on the other side of the CSR electric water pump.

Here is a bottom view of the zig zag plumbing I did to clear teh accessories with the small block water pump.

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Lingenfelter made a very small number of 4th generation F body versions of the SuperRam plenum. The standard TPI water neck didn't fit...

So I modified the much shorter LT-1 water neck to fit.

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Notice the extra clearance I have now after taking the scissor jack to the cowl. Still a tight fit and I had to make a few special tools to get to all the top and bottom plenum bolts.

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I had a huge vacuum leak on first run. Even with the throttle body blocked and iac air port plugged, it was idlign at 1800-2000 rpm. Before I went thru the chore of pulling the plenum apart again, I made sure the throttle body or gasket wasnt to blame. It still ran at 11800+ with this wood plate blocking the inlet.

I expected the vacuum leak to be caused by ripped plenum gaskets, but it ended up being 2 gaping unplugged vacuum ports that I overlooked the first time around.

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I made these 2 plenum gaskets

I made the best of having to take the intake all back apart, and added a t block to the oil pressure port for a mechanical guage and the factory sending unit.

first run

Time to install the new walbro fuel pump. Cutting an access panel is so much easier that dropping the tank.

Taped off the area to be cut...

Viola!

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The stock pump next to the new walbro pump

Notice the wet towel and water spray bottle. It made me pretty nervous cutting right over the fuel tank with a hi speed cut off wheel, so I layed the wet towel over the seam and followed it with the wheel. I also continuously sprayed it down with water.

The new pump didn't quite fit in the container. One of the notches had to be ground down, then it fight right in.

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This is only temporary I swear!

The DFI computer has no vss conditioning system as the stock LT1 PCM does, so I scored this stand alone VSS signal buffer off a 1991 S-10. It converts the AC sine wave from the VSS sensor into an open collector active low output of whatever ratio it is jumpered for on the PCB.

These GM DRAC modules have a range of 0.5 to 1.0 output ratio. If I keep the current 17 tooth vss reluctor wheel that's in my T56 trans, the module will need to output at a ratio of 0.28 for the 2.73, and 0.38 for the 3.73. These ratios are both lower than what these modules can do. I considered adding a frequency doubler to the input (effectively creating a 34 tooth input signal), but in the end I decided to change the reluctor wheel to a 40 tooth wheel. This will put me at 0.65'ish and 0.76'ish, well within the range of what these things can be calibrated for. Why did GM change to 17 tooth anyway for f car T56 only?? Even the GM aftermarket version of the T56 came with the 40 tooth wheel. Also note that I soldered a dip switch to one of them for easy calibration.

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Here I'm running the LT1 PCM on the bench and feeding a sine wave into the vss input pins (A31/A32) and monitoring the output of the VSS output to speedometer pin (B8). It's hard to see the scope, but for for a 1.2Khz sine wave (roughly 55-60mph), I get a 55Hz square wave.

I hooked up the stock LT1 PCM to get a working speedometer for the time being. All it's doing is taking the vss sensor signal in and spitting out a conditioned vss signal to the speedometer.

Here is the rare 40 tooth reluctor wheel for a T56 trans, shown above a photo of the 17 tooth gear that was in my trans. Most T56 specialists told me there was no such thing. Bob Hanlon from Hanlon Transmissions in PA, finally set the story straight. They were discontinued from the aftermarket versions of the T56 early on, and replaced with a mechanical speedo gear. Bob had a few in his shop, and hooked me up!

Got all my regualr guages to work too finally! Silly ground wire.

First trip out to Armada and Goodells on a wet night, cruisin down the dirt roads Dukes of Hazard style. Yee-Haw!

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