"Shaft," Jim "Campy" Campisano's...
"Shaft," Jim "Campy" Campisano's '65 Coronet 500, would be our test mule for this swap. We had already gained 3/10 with the intake swap; now we would see if the new EPS 800 would show an increase over the well-tuned EPS 750 on the car.
When doing bolt-on-style parts exchanges, a number of variables need to be considered. What other parts need to be exchanged? How easy is the swap? What is required to adapt them to this or that vehicle?
The Edelbrock Performer Series (EPS) carburetor/intake manifold combinations have proven to be an easy exchange for the stock Carter/cast iron factory components. Now Edelbrock has gone one step further with the EPS800, an 800-cfm monster perfect for deep-breathing and/or stroked engines. These are basically king-size versions (#1412 manual and #1413 electric choke models) of the Performer 500-, 600-, and 750-cfm models, sharing the same-style metering rods and jets while offering increased venturi area and larger throttle blades.
Why make the swap? In addition to the weight savings between the iron and aluminum intakes if you are inclined to make that change, the EPS carbs are a direct replacement for the AVS Carters found on so many muscle Mopars. In the past, it was common to swap the larger 750 AVS onto a 340 or 383 in place of the factory-installed 625-cfm version. However, metering rods, primary side jets, and other hardware associated with the ancient AVS have become scarce and expensive. Our strip testing in the past has shown the EPS line is equivalent to the AVS, with increased tuneability and driving enjoyment. You can either move up to a 750- or 800-cfm EPS on the factory intake by enlarging the throttle bore holes, or go for the gusto with an accompanying Performer intake, which is what we did.
What initially intrigued us about this test was an Edelbrock advertisement stating the new EPS800 was good for 22 horses and 26 lb-ft torque on a 350 Chebby. We have an engine close to this displacement in "Shaft," Jim Campisano's '65 Coronet 500, which is equipped with a mildly worked 383. This car was used for many strip tests in the old High Performance Mopar magazine, and would be a fitting platform to give the 800 a "real engine/real car" workout. Shaft had benefitted from an EPS 750 swap in place of the stock 625-cfm AFB in 1997, so we had a baseline of both stock and the present aftermarket carb.
Shaft had also received one of the then-new Edelbrock 383 Performer RPM intakes five years ago, replacing a 383 Road Runner intake ('68-'70 casting-301). That had been worth a full 3/10 of a second coupled with the original 625, and the swap to the EPS 750 and some tuning (richer metering rods) had shaved another 1/10 off of that. The question was, would this mild 383 benefit from even more carb by replacing the dialed-in 750? While 800 cfm may seem like a lot for the 383, we've seen benefits on running up to 300 cfm more than the factory recommended size. Of course, it would be way too much for a 273 or 318; an EPS 500 or EPS 600 version would be a better all-around choice on engines that size.
This is the 750 as we got...
This is the 750 as we got ready to take it off the car. This has been a great carb for this combination, and was already scienced out after almost five years of abusively track testing new parts.
Normally, we schedule our tests at Raceway Park in Englishtown, New Jersey, a few weeks in advance, which means we are at the mercy of that day's weather. For this test, we ended up with the typical midsummer Garden State heat and humidity-not conducive to getting impressive quarter-mile times. This is the reason we tried to do these tests the same day; the weather can be worth a few tenths itself. You will see in the accompanying chart that the temperature was near three digits most of the day.
Campy (that's James Campisano to you law-enforcement types) brought along a pair of mounted Hoosier 26x9 stickies to get consistent no-spin launches. As it was, we needed a one-hour cooldown after driving the car to the track, and Jimmy Napp laid down some fresh glue to help get the starting line in shape while we waited. The Napp family has owned and operated the facility since they opened it in 1965.