Demon 1921 Street Demon 625 Calibration Kit

had to by additional jets for my secondaries. carb is a pain to tune.

This tuning kit for the Street Demon 625 CFM carburetor has all you need to tailor the carb to your engine. I have a 1966 Pontiac 2+2 with a 421 (now 429 with the overbore) and this carb works very nicely on the engine. In my case, the best tune was just to use the "richest" parts in the kit. I ended up with the biggest jets on both the primary and secondary side and the thickest step-up springs. The step-up rods are the next to richest set. Most people would have used the 750 CFM carb on an engine this size, but I prefer the low speed drivability of the smaller carb over the few extra horses on top. Besides that, this carb is already 75 CFM more than the original Carter AFB. Out of the box, the carb is probably tuned very well for a 350-ish sized engine with a relatively short stroke; which was way too lean for my engine. Many people with engines in the 300-400 cubic inch range can just bolt this carb on and go. All in all, I love the carb and this kit was an absolute necessity for my particular engine. You may not need the tuning kit, but if you do it is invaluable.By the way, this kit includes all of the original stock jets and step-up rods. This is a great idea in case you do not have a new carb to tune or you somehow lost some parts. Others have criticized this as a waste of money, but it is worth it in my opinion.

Box was not taped closed. One of the metering rods is missing and one was bent.