Testing engines is cool. Sometimes, ok almost all of the time, when testing a new combination, we walk away with a feeling of accomplishment, even if we didn't make any more power that day. And the feeling's even better when we do make more power, or, as in the case of Major Mouse Pt. 05, more AVERAGE power and torque is what we walked away with thanks to a pair of Edelbrock's E-TEC 200 cylinder heads.
We usually try to remain passive and unbiased in our reporting of the day's dyno events. But every time we've tested and engine using Edelbrock's E-Tec line of cylinder heads, we've been astounded at how much power they can bring to the table. And we like to give credit where credit is due to the folks in the engineering departments of Edelbrock for coming up with a cylinder head design that can work equally well on a little 350 or a big 427-inch small-block. When you look at this month's tests, you may not see a huge increase in power compared to other months. But, at this level, any gains, especially those in average power, which is power throughout the entire rpm band, are worth the praise. And when tested with Edelbrock's matching Vortec-style intake manifolds, both the Performer RPM Air Gap and Super Victor, Major Mouse has broken almost all of its own personal records. In past tests, only the Brodix RR180 heads made more peak torque, eclipsing the E-Tec 200's by 7 lb-ft at 4,200 rpm (572lb-ft to 565 lb-ft). However, if you look at the start of the run, you'll see that MM made more low-end torque with the E-Tec's than it has in a long time which means that MM has set the new standard for power this month.
In Test 05 we installed Edelbrock's single-plane Super Victor Vortec intake manifold and got the highest peak horsepower to date, 526. Of course, as with all good things in the world of horsepower, there was a trade off when compared to the torque made using Edelbrock's dual-plane Performer RPM Air Gap Vortec manifold where we saw some great, if not record setting peak torque figures of 565 lb-ft. As is almost always the case when swapping from a single-plane intake manifold to a dual-plane, low-end torque was traded for top-end horsepower and the power curves in the accompanying graphs show the details.
But, it's all good, because this is yet another example of two, tailor-made combinations that can fit a variety of applications. The E-Tec 200's along with the Perf Air Gap manifold would be great to power a heavier car or truck, while the Super Vic manifold would be best suited to a lighter car that can hook and launch. And keep in mind that these power figures were generated with a mild camshaft in this big small-block that'd idle like a kitten and roar like a lion.
MAJOR MOUSE PART 05 - TEST 05:
As is our usual format, the crew at Speed-O-Motive once again left everything else the same and only swapped heads and intake manifolds this month. All other items in this test including: timing, jetting, cam installed position, etc., were duplicated from last month. They also reused the same COMP Cams 1.6:1 rockers, and the same Demon 750 carb, then bolted Major Mouse back onto their DTS dyno to see how much power it could crank.
SPECS for MM05-T05:
427 cid, 11.0:1 cr, 4.125"-bore Mowtown iron 4-bolt block, 4.00"-stroke Lunati crank, 5.850"-inch Lunati rods, Lunati pistons (14cc dish) installed @ "0" deck, Lunati Moly rings, Edelbrock E-Tec 200 heads (64cc chambers, 200cc runners, 2.02" intake valves, 1.60" exhaust valves), Edelbrock Super Victor Vortec intake manifold, Edelbrock Performer RPM hydraulic roller camshaft installed at 108-degree intake CL (234/238 @ .050, 296/300 adv, .574/.584 lift w/ COMP 1.6:1 rockers, 112 LS), Demon 750 carb, 32 degrees total advance, "0" degree Crank Angle Offset (C.A.O.)*, 91-octane Shell gasoline. Tested on Speed-O-Motive's DTS dyno.
SPECS for MM05-T06:
Same as T05, but with Edelbrock Performer RPM Air Gap Vortec intake manifold
*C.A.O. refers to the setting on the Pertronix "Second Strike" ignition box. It re-fires the spark plug after its initial firing, such as 32 degrees BTDC on the first firing, and then once again at 30 degrees BTDC if the box is set for a 2-degree C.A.O. In this case, as was the same last month, Major Mouse responded best to a C.A.O. of "0" degrees, meaning there was actually no second strike of the spark plug. In the past on some other engines we've found extra power by re-firing the plug around 2-3 degrees later, but not this time
|MAJOR MOUSE COMPONENTS|
|FOR PT05: TEST 05 & TEST 06|
|CAM||EDELBROCK HYDRAULIC ROLLER (PN 2201)|
|CARB||SPEED DEMON 750|
|HEADS||EDELBROCK E-TEC 200 (PN 60989)|
|IGNITION||PERTRONIX DISTRIBUTOR, "SECOND STRIKE" IGNITION BOX*|
|LIFTERS||COMP HYDRAULIC ROLLER (PN885-16)|
|MANIFOLD||EDELBROCK SUPER VICTOR VORTEC (PN 2913)|
|MANIFOLD||EDELBROCK PERF RPM AIR GAP VORTEC (PN 7116)|
|PISTONS||LUNATI DISHED FORGINGS|
|ROCKERS||COMP CAMS 1.6:1 PRO MAGNUM (PN 1302-16)|
|SPARK PLUGS||ACCEL (PN 8191)|
|Super Vic||Perf RPM|
|* indicates Major Mouse's personal record-breaking performance|
200 CYLINDER HEADS
(200cc intake port)
When shopping for cylinder heads there's lots of choices to consider and not every one of them will work best in every situation. So it's important to collect as much data as possible and then make your decision based on what you've learned. When comparing cylinder heads, it's important to look at other figures besides just airflow. Port volumes, chamber shape and size, valve sizes, angle and locations, how much spring/lift they can take and will it match your camshaft? These are just a few of the items that you should make your decision on, not just the power they produced in some magazine story. I also personally feel that a good indicator of how well a cylinder head will work is it's ratio of intake to exhaust flow, listed as "IvE flow" in this chart. Although this is not the "Holly Grail" of horsepower, it does indicate a head's potential to move air into and out of the cylinders effectively. A head with a ratio of less than 60% is not a very effective air mover, particularly since it indicates that it can move air into, but not out of, the cylinders. A head with a ratio of over 90%, although rare, is capable of extremely good power numbers so keep an eye out for it. Check out the very high 90% IvE flow at the low .200-lift area of the Edelbrock E-Tec 200 heads. This is an area of critical performance for any head, but particularly a street head that won't be run with much lift. Since the valve will see this area twice during every cycle, once on the way up and then again on the way down-as opposed to seeing max lift only once in every cycle- low lift flow figures are often overlooked, but very critical to making the best power.
|Intake port: 200cc, 2.02" intake valve, 1.60 exhaust valve|
|Figures shown at 28-inches water depression|