Nitrous
Nitrous is everybody's friend. You've just gotta know how to handle it. Brul's suggestions were simple: get with a good system in the first place, don't exceed a nitrous shot in excess of one-third the engine's total power output, and pull 2 degrees of timing out of the ignition for every 75 hp of nitrous.
The Zex system we chose is of the highest quality. We installed the Zex billet perimeter nitrous plate (it spays the nitrous/fuel mixture through evenly distributed small holes around the inside of the plate's inside perimeter) and made another pull without the nitrous to see what effect the 3/4-inch plate had. Normally, you pick up a little power with a spacer, but as a testament to how dialed-in our manifold/head/cam combo was, we only saw a best of 544 hp and 567 lb-ft of torque, picking up 4 hp and losing 1 lb-ft (as compared with no spacer).
Brul then pulled 4 degrees of timing out of the picture, filled the fuel cell with 100-octane Rockett Brand racing fuel, and with the engine at 4,000 rpm, hit the button. We nailed just shy of 700 hp with a best pull of 698 hp and 765 lb-ft of torque. In case you're a little slow with the math, that means the Zex system actually overdelivered on the power, giving us 154 hp from a supposed 150hp shot. Way impressive. We could've messed with bottle pressure to eke out a little more to claim 700 hp, but Brul asked, "Why not just go up a jet size for a 175hp shot and shoot for 725 hp?"
However, even though Mondello is confident this engine will suck a 200hp shot all day long, we decided to play it safe. We're happy with the knowledge that nearly 750 hp and probably close to 900 lb-ft of torque is on tap with a simple nitrous jet change.
Overall Package And Driveability
Mondello calls it a Pro Street engine, but it's really not the wild beast the name conjures up. Granted, you're not going to want to rockcrawl with an engine like this, but for our project's intended purpose as a Glamis sand rig, Ocotillo hillclimber, and maybe even a quarter-mile screamer, it's bang on the money.
The air/fuel mixture and exhaust travel in gaseous balls through the engine known as pulses. By maintaining velocity with moderately sized intake ports of around 300 cfm and efficient exhaust ports, in conjunction with a camshaft that opens the door (valves) accordingly, these pulses are able to stack more closely together to create fat torque lower in the curve and deliver a very high brake mean effective pressure (BMEP). The BMEP is an indicator of how efficient an engine is and allows a comparison of its performance evenly to another engine of a different type with different characteristics. For example, our 468's BMEP came in right at about 170 psi. As a comparison, Brul says most of the normal 91-octane engines he sees are in the 160s. A dead-stock '70s Chevy V-8 may be in the 140s, and a NASCAR V-8 may come close to 200 psi.