For the sake of comparison, we looked at the numbers from a set of factory GM iron Vortec
Edelbrock E-Street Heads
429 hp at 5,300
481 lb-ft at 3,900
The E-Street heads are made in the USA to compete with imported cylinder heads priced less than $1,000. Since they flow better than Gen I factory iron heads, allow for more valve lift than Vortecs, and weigh less than both, they should do a good job as entry-level street heads. They are the least expensive small-block Chevy heads in the Edelbrock lineup.
The heads are available with either a 64cc or a 70cc combustion chamber and have 2.02/1.60 intake/exhaust valves. The 185cc intake ports have a peak flow of 230 cfm at 0.600, and the 60cc exhaust ports flow 167 cfm at 0.600 lift using as-delivered parts on the Westech Performance flow bench. What's more important than the peak, however, is the midrange numbers of 176/125 cfm at 0.300 and 212/149 at 0.400 lift. That's where a camshaft with a usable duration with these heads will live.
The differences among the E-Street and the more expensive Performer and Performer RPM are the little extras and the finish work. The E-Streets have all the performance goodies of the other two heads without any hand blending of the entry or exit of the port or bowls. They also lack the Helicoiled exhaust boltholes and have a smaller, 1.250-inch valvespring. The good news is, because they are the same casting as the Performer and RPM, the blending and the larger 1.460-inch spring can be added if you crave a little more lift and power.
On the dyno, the E-Streets creamed the 882 heads all the way through the power curve with an easy gain of 74 hp and 52 lb-ft at the peaks. The extra inches provided by the 4.00-inch crank added torque and horsepower all over the chart. Past tests we've performed with similar-flowing entry-level heads on a 355 engine barely crested the 400-lb-ft mark at peak. The 408 with roughly 10 additional degrees of cam duration and just over half a point more compression made 400 lb-ft, as low as we dared to pull the engine, and peaked at 481 lb-ft.
To get the cost of the heads down, Edelbrock used a 1.25-inch valvespring that is good for
The E-Street heads will bolt to any pre-'86 small-block and have all the trick stuff, such
The original heads we used had a 76cc chamber, so we picked up 0.7 point of compression wh
We bolted the heads onto the 408 small-block and added a set of Manley 7.900 pushrods and
We ran the baseline for the head test with the 882 heads from the tests in the Aug. '09 is
We ditched the stock head bolts and used a set from ARP. Using ARP bolt sauce, we torqued
The heads were tested on Westech's Superflow bench with 28 inches of depression using as-delivered valves, a 4.000-inch bore plate, and an exhaust flow tube.