350CI Built Engine - The Big Squeeze

This was a lot tougher than we thought. Some time ago, Speed-O-Motive built a test engine whose only purpose in life was to live on the dyno and test our harebrained ideas to make more power. While being a very tough little brute, its size was nothing of interest: just 355 cid (just like you'd find under the hood of many of today's hot rods).

What made this mule different from all the rest was the sum of its parts, as they were the toughest in the land. It was built to take tons of abuse and live through thousands of dyno pulls before finally being laid to rest. Up until that time we wanted to see just how much nitrous we could throw at it, and it stayed pretty healthy. The little 355 had made as much as 585 hp with a Weiand Hi-Ram and 700 hp with an ATI blower and ACCEL EFI.

But now we wanted to go with 12.5:1 compression and push the limits of a pump-gas-burning motor using only bolt-on parts. By that we mean that none of the parts we'd installed had ever been modified to work, fit, or make more power--every part in or on this baby came right off the shelf and out of its factory box.

Not a bad deal, all things considered. But could we make 1,000 hp with squeeze? Or how about 900, or maybe just 800 hp? No way to know unless we tried, so we called up the Edelbrock guys and had them send over one of their very trick double-crossbar nitrous plates to see if we could hit the sky.To properly evaluate the benefit of the big Edelbrock nitrous plate, we first had to evaluate the performance of our little motor on its own. So we tuned it naturally aspirated (N/A) on the DTS dyno first and ran it on 91-octane. It worked well, but we really thought we'd make 600 hp without the squeeze. Oh well, still pretty damn good for a bolt-together 355-cid pump-gas Mouse.

BUILDING THE MINI BEAST
A 355-cube, 400-plus-horsepower Mouse ain't too bad, but now it was time to do the magic with the bolt-on goodies. First, in order for this little nitrous beast to live and make power, a few things needed to be installed. In addition to the tough rotating assembly (which included a forged Lunati crank, billet Lunati rods, and custom domed pistons), the iron four-bolt Motown block meant we wouldn't have to worry about the bottom end coming apart any time soon. A complete Moroso oiling kit also helped ensure our Mouse would live. Up top we asked COMP Cams to grind a custom nitrous roller cam with lots of duration and lift and a 4/7 lobe swap to enhance power a little further. (Actually, COMP first made an even bigger cam for us to try, but it wouldn't fit because the valves hit the pistons!) But other than the really big cam we special-ordered, all the engine's parts came right out of a Jeg's catalog.

INDUCTION
When running high-power nitrous in a motor like this, there's really no need to run a small carb and/or small intake manifold. So we asked Edelbrock to also supply its Super Victor intake setup for a Holley Dominator carb. Then the guys at The Carb Shop screwed together a nitrous-specific Holley Dominator (PN 9375) that would flow about 1100 cfm. The setup was then bolted to a pair of Edelbrock's 215cc Victor Jr. heads wearing COMP Cams 1.6:1 Magnum roller rockers. Armed with our mighty motor, a little 91-octane pump gas, and lots of 114-octane race gas, we headed over to Speed-O-Motive's DTS dyno to see what we could literally squeeze out of it.

SQUEEZE PLAY
When it came time to hit the squeeze, we stayed on the fairly conservative wild side for safety. After all, we were only looking to make 800 hp and we just got there with this hit. Note the lower initial power before we hit the N2O button. This is a result of us retarding the distributor 4 degrees to augment the max 9.9 degrees the MSD box could pull out, giving us a safe 14-degree total retard when we hit the squeeze. Also, notice how the extra N2O power ramps up gradually starting at 4,000 rpm when we hit the button on the Edelbrock Progressive digital nitrous controller. This is to save the bottom end of the motor from the incredibly hard hit with the dyno fully loaded, and would also indicate good traction control at the track if this setup were in a car. Here are the numbers with the 114-octane race gas, #54 fuel jets, and #54 nitrous jets.

POWER-MAKING FORMULA
While it can be noted that on a bigger engine, or perhaps one built specifically for nitrous, more power might've been made, we're here to tell you that 800 hp is possible from an otherwise pump-gas- using 355 small-block. It's not easy--and it's definitely not cheap--but it can be done. And the coolest thing about all this is that as we had hoped for, all these parts were true bolt-ons.

So if you can torque a wrench, you can build this brute. Of course, the key to our giant power was by far the Edelbrock N2O plate with its four solenoids and twin-crossed spray bars; it's capable of making tons of go. As always, use caution whenever you're trying to squeeze so much power out of such a small package, or you'll suffer a fate you may never care to see.