Modified Mustangs & FordsHow To Engine
Carbs, And Intakes, And Dynos, Oh My!
Quality Time In A Dyno Room With A 347ci Ford Unfolds The Truth About Carburetor-Intake Combinations
It's that age-old question-Which intake manifold and carburetor system do I use on my new project? The simple answer is that every project is unique and that it's personal preference, but with the help of the Barry Grant R&D engine dynamometer, we explore some of the popular choices and come to some conclusions.
Barry Grant's R&D facility had a 347ci Ford small-block already on the dyno, and it was typical of most street builds with Dart Wedge heads (2.02/1.60 valves, 195cc intake ports) and a 10:1 compression ratio. A Comp Cams hydraulic roller camshaft (PN 35-424-8) with a duration of 224/230 at 0.050 and 0.513-inch lift, along with 1.6:1 roller rockers, to round out the engine package.
Within the scope of this test, we were able to try four different induction setups, the first of which was a typical Edelbrock Performer RPM dual-plane intake manifold with a 650 Mighty Demon carburetor. The other three we tested were all Barry Grant pieces, each of which will offer a unique look and power potential. While we could have tested a single-plane intake and bigger carburetor, we wanted to see just what the latest in induction designs had to offer against the tried and true single four-barrel.
Our baseline runs were made with the 650 Mighty Demon and Edelbrock Performer RPM combination. In this configuration, the engine made peak horsepower of 380 hp at 5,900 rpm, and peak torque of 425.3 lb-ft at 3,900 rpm. This combination offered a tremendous amount of low-end torque from 3,000 rpm to 4,600 rpm, but the twist fell swiftly beyond that. More than 375 hp was made from 5,100 rpm all the way through our cut off at 6,000 rpm. This would be a good setup for a heavy car or a truck, with the low rpm torque and solid top-end horsepower that it offered.
With the baseline numbers recorded, BG's Gary Stropko and Dale Eicke went to work swapping the intakes. The Barry Grant Aero-Ram Intake is a relatively new piece, and we were eager to see how it stacked up to the Performer RPM using the same 650 Mighty Demon Carburetor. After a bit of warm up time, we began to get the answers. Peak torque came in at 412.5 lb-ft at 4,500 rpm, and the peak horsepower of 395.9 appeared at 5,600 rpm. While the peak torque was down from the Performer RPM, it had moved up in the rpm range, and excelled past 4,500 rpm. The torque curve was considerably flatter overall. More than 385 hp was made from 5,100 rpm all the way through the 6,000-rpm limit. In addition to this, BG told us that one of the key benefits of the AeroRam intake is that the even runner design allows a very low idle.
For a really cool street rod look, Gary and Dale bolted on the Four Deuce Induction Madness setup, utilizing four Demon 98 Carbs and intake risers on the AeroRam intake. This system involves one of the more complex linkage setups, but everything is included in the Barry Grant kit. With the four Deuces parked on the AeroRam, you can imagine the wow factor you'll get when the hood is popped at the Saturday night cruise-in. But how does it run?
With a peak torque of 392.7 lb-ft at 4,400 rpm, and a peak horsepower of 363.8, the Four Deuce system, relatively speaking, isn't the best choice here for all-out power production, but it will certainly pull hard throughout the powerband, and probably clean up at the car shows too.
Photo GalleryView Photo Gallery
The last BG induction system we tried was the long-awaited "BadMan" 675. It's probably one of the most unique looking carburetor systems that you can bolt onto your Ford. On the dyno, the BadMan made its peak torque of 407.1 lb-ft at 4,500 rpm, and peak horsepower of 398.9 hp arrived at 5,800. With a similar torque curve to the 650 Demon, the BadMan stood out at the top end, offering more power past 5,500 rpm than all of the other induction combinations. In this area, we noticed that the horsepower leveled off, which probably means we've found the limit of the camshaft that we are using. Had this engine been designed for a higher rpm range, the BadMan would likely have kept making horsepower.
For this test, the BadMan on the AeroRam Intake won the horsepower race, edging out the Demon 650 carb/AeroRam combination. The peak torque "champ" was the 650 Demon on the Performer RPM manifold, though the BadMan 675 did offer a similar average number. In the end, the absolute numbers here are really a reference for a 347ci small-block engine combination. Your cylinder head and camshaft choice may offer slightly different results. After reviewing the information here, you should be able to make a better decision for that project in your garage.