This bumper is designed to be used with stock '74 and on 911, SC and Carrera fenders (GT Racing Part #30). The oil cooler opening is 23 1/2" x 6 1/8". The bumper has brake cooling ducts and provisions for lights. This bumper is by far one of GT Racings most popular bumper! Lot's of folks use this bumper to quickly change the look of their car from the old impact bumper style to the old school narrow body RS style. This bumper is also very poular with the stock tpe of classes in racing and the folks who want an easy light weight solution for their weekend "Find a Curvy Road" car! Mounting hardware is included. Average weight is 9 lbs. GT Racing also recommends buying the grill (part #43C) and the companion rear bumper (part#45). Call for carbon fiber prices.