Virtually all of the engines...
Virtually all of the engines in this story rely on hydraulic- or solid-roller cams. Rollers are more expensive, but they offer tremendous valve lift for the duration.
Big horsepower and torque...
Big horsepower and torque demand a great cylinder head. The key is to choose the head that best matches your performance goals.
Not all Rat motors require...
Not all Rat motors require rectangle-port heads. Its possible to make 650 hp from a ported iron oval port head. This is the difference in port-opening size between an oval- and rectangle-port head. Velocity plays a key part in making more torque with the oval-port head, especially on smaller-displacement Rat motors.
Many of these big-inch Rats...
Many of these big-inch Rats used a 1,050- or 1,150-cfm Dominator carb to make these big-time numbers. But if you want to run on the street, these carburetors may be difficult. A smaller, square-flange carb like this Barry Grant Mighty Demon or a larger Holley HP-series carb would be the best bet for the street.
With long-stroke cranks in...
With long-stroke cranks in big Rat motors, decent oil pans and windage trays are necessities. This is a simple Milodon splash tray that fits between the back of the oil pump and the rear of the pan to prevent the oil from climbing the back of the pan on dragstrip starts.
Keep in mind that the Gen...
Keep in mind that the Gen V and Gen VI engines use a different cam drive than the Mk IV.
This is the cam drive snout...
This is the cam drive snout on a Gen VI hydraulic-roller cam that requires the use of a thrust plate on the front of the block to prevent cam walk.
Headers are a necessity at...
Headers are a necessity at these power levels, but the larger pipes can be a challenge to fit in the chassis. Slightly smaller headers will fit better and improve torque but will cost a small amount of horsepower at peak rpm.
Intakes are also an essential...
Intakes are also an essential part of the power equation. For 500ci-or-larger big-blocks, a single plane like this Edelbrock 2907 Victor 454-R Dominator intake makes outstanding power. Edelbrock also sells an adapter to run a 4150-style carb on this intake.
This is serious stuff. Sure, small-blocks make great power for their size, but thats like saying almost is good enough. It just doesnt cut it. If youre looking for real power, then get serious with a Rat motor. Were not talking about a 396 or even a 427. If youre gonna step up to a Rat, make it at least a 454 or a 468. Better yet, throw a quarter-inch arm in a 454 and build a 496. Or you could just let those other guys seem conservative and build a nasty 540. Thats what the big dogs are doing. Dont let the displacement-envy crowd fool youon the street or the strip, size matters.
Now that weve thrown down the gauntlet, lets step up and talk about some real power. Were going to outline a selection of powerful big-block combinations that should point you in the right direction. Our sanctified guide for this big-block power tour is none other than Flowmasters own dyno guru and NHRA Super Gas racer Kevin McClelland. Over the years, he has tweaked several powerful big-blocks, and he was kind enough to pull up several examples of righteous Rats that have run across the Flowmaster dyno.
Well start with a mild, oval-port big-block torque package for those looking for outstanding grunt in the under-4,000-rpm range, but well concentrate on several big-block combos intended to excel down the quarter-mile. These are not daily-driver packages, but rather the big-cam monsters that come out only at night to prowl the streets. Pretenders beware, its a jungle out there and the king is generally a Rat with a big arm.