carb

holleyavenger

The stock car came equipped with a 4bbl manifold and a Motorcraft/Holley carb.  It was also, I suspected, one of the reasons the car was running so poorly, so I went to Morgans in Walnut Creek and they sold me a Holley Street Avenger 670cfm.  I decided to buy one from them because I don’t know anything about pairing cfm ratings with engines, and buying a plug-and-play carb simplified the initial installation immensely.  It has an electric choke and an accelerator pump that squirts a visible (and considerable) shot of gasoline into the carb every time you open the throttle.  I topped it with a 9″ Mr. Gasket air filter.

The Holley Street Avenger carb came with two different sized throttle linkage balls.  I used the smaller of the two, which I’m guessing is for Ford applications.  I based my linkage on Brian’s brother’s design.  It uses the stock throttle linkage and only requires one bend of the cable.

I went to the Pick-n-Pull and pulled two Ford throttle cables, hoping that at least one would be about the right length.  I think I ended up using one from an old carbed thunderbird – it’s very short and had to be shortened more.

linkage01

linkage02

The white piece is UHMW, an inexpensive, slippery plastic not unlike Delrin.  It is drilled out for the inside steel cable, then counterbored for the sheath.  It holds the sheath in place while allowing the cable to move freely.  I bolted it onto an angle aluminum bracket, but the location of the bracket was dictated by where All-Tech had placed the brake proportioning block.  It’s held on by one of the 6mm firewall bolts at kind of an odd angle.  It’s ugly and I plan on fixing it in the future.

I secured the cable to to the throttle ball by “crimping” it with a piece of brass folded upon itself and bolted down hard with a 1/4-20 bolt and nut combo.  I am unsure how safe and reliable this design is, but it seems to be holding fast so far.  This design also allows me to adjust the length of the cable, which has proven to be useful.

I retained the stock throttle linkage bracket, but because the stock carb sat on top of a EGR plate, it is too high to work with the Holley.  I had to trim this down and redrill it so that it lines up properly with the throttle crank.  The stroke of the pedal will probably have to be tweaked (there is a stopper up near the top of the pedal and another stopper down on the floorpan.  Both can be adjusted).

holley blue mounting location

fuel pump system

Fuel is pumped to the front of the car by a Holley Blue fuel pump mounted at the stock location and soldered in to the stock wiring.  The manual recommends two filters so I put a high micron one in line from the tank to the pump, then a low micron one up near the carb in front of the regulator.  The fuel travels under the car via a AN -6 steel braided line, up to the regulator. then up to the motor.  When you go to tune this regulator, buy or borrow an in-line fuel pressure gauge; it will be invaluable.

fuel filter near carb

I chose to go with a single feed line, no return line setup, but your pump will be much happier if you plumb a return line.  The pump itself is very loud inside of the cabin of the car and I got the impression that it was working very hard.

Overall this carb worked OK but it was very fuel inefficient and I felt like it could have used tuning.  Holley claims that their Street Avengers are ready to run, but I could tell the car was running pretty sloppy.  This is a good way to get your car on the road, but you will have to spend some time at a dyno to get it running well.

carb installed

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