Holley Sniper

[Green411]

Thought you might be interested in an update after 18 months or so.

The car still has the original Torqueflite 3 speed auto transmission and original back axle. With the original carb I got 13-14 mpg imperial on a run and about 11-12 mpg running around locally with 10-20 mile drives. Driveability left a lot to be desired and starting under most circumstances was poor.

With the Sniper I get 15-18 mpg on a run (absolute best of 19mpg at no more than 60mph and no harsh acceleration) and 13-15 mpg running around, all imperial.
Drivability and starting are greatly improved on top of the 10-15% fuel consumption improvement.

It's all based on the Sniper's self-learning, with no manual tuning done. The original ECU failed after about an hour of running, but Holley accepted liability immediately and I got a free replacement from Summit which has been fine.

I've had a couple of instances of a spit-back through the throttle body while pulling away during warm-up. This was traced to tbi mounting bolts loosening up for some reason, presumably causing a slight air/vacuum leak.
I use the recommended sealing plate between the square-bore throttle body base and the stock spread-bore intake manifold. Have tried it without it, but got an air leak.

Overall I'm very pleased. Would I do it all again? Yes, in a heartbeat.