Skip to main content

Reply to "Too much YouTube? I'm about to order a Holley Sniper EFI system"

Nothing is simple on these cars! What carb you use depends on how hard you intend to drive. A 780 (or a 750) Holley will add power and reduce fuel mileage to maybe 12 mpg. The nearly ideal size is a Holley 700 or a tuner-altered 650 with a dozen changes. Set up properly, expect 18-20 mpg from a tuner carb. Maybe. EFI can deliver 22-25+ mpg with the same performance.

Is your car a '71-'72? Because another way out for EFI without having a vulnerable christmas tree of fittings hanging down from the tank is to pull the left rear quarter glass, then reach in and remove the long fuel tank sender thru the window opening. The bolt-in '73-up sender has a built-in fuel-out line, making the welded fuel-out port on the early tank ideal for an EFI return. The unservice-able OEM internal line often rusts thru inside, allowing you to only utilize fuel down to the first rust pit- about half a tank. As a fuel return, even a rust pitted line works fine.

Early tanks also had an equally unservice-able nylon fuel filter on the end of the welded line, that builds up varnish & restricts fuel flow. Some fell apart over 50 years; if its still in there, we recommend reaching inside the tank thru one of the large openings and tearing the nylon off with a long rod, then fishing the pieces out. Be VERY careful working around a nearly-empty gas tank!

You may get lucky, but the fuel tank drain plug is normally stuck solid. The lightweight steel tank is made of such thin sheet that excess pressure on the tank plug will cause the sheet metal to buckle into frightening waves. It may actually tear! Some shops have had success using a large air hammer set at a lower pressure, which reportedly loosens the plug after a few minutes of unbelievable noise. Others drill it out and tap the straight thread M22 hole for a SAE pipe thread. If you do this, do not use an electric drill; when the drill bit first breaks thru, residual gasoline will run down over the electric drill motor and life can quickly become "expensive & exciting".....

×
×
×
×