Got questions?

We’ve got the answers—the Summit Racing tech department tackles your automotive-related conundrums. Last week, we tackled a rich air/fuel condition. This week, we’re helping maximize some already-potent Mustang modifications with larger fuel injectors and airflow upgrades.

M.T. • Frackville, PA
Q: I’ve been upgrading my 1989 Ford Mustang LX for quite some time. It currently has an Edelbrock Performance RPM 347 EFI engine with a BBK underdrive pulley set, Edelbrock 75mm throttle body, JBA Cat4ward headers, Snow Performance Stage-2 Boost Cooler, and a supercharger system. I’m still running the stock 19 pounds/hour fuel injectors and mass air meter. What size injectors and meter should I use to enhance my current mods? Also, what’s the best gear ratio to run? My Mustang has the stock automatic overdrive transmission.

A: You’ve got a great power-building setup, but we’d recommend stepping up to a set of 24 pounds/hour fuel injectors and matching your existing throttle body with a 75mm mass air meter. This combination will give you a steady rpm range without any power-robbing flat spots.

As far as gear ratio, we’d recommend using a 4.10 ratio with that automatic overdrive transmission. It’ll put the power to the pavement on the street and at the strip.