The Quest For A Streetable Ram Air V
While most collectors would tremble at the thought, Chuck was actually interested in driving his Judge to cruise nights and occasionally around town. As a result, he was looking for a combination that was docile and user-friendly, yet offered plenty of power. If that meant some top-end performance would be sacrificed to achieve those goals, so be it.
Hearing good things about DCI Motorsports from other Ohio Pontiac fans, Chuck called upon proprietor Don Johnston to tackle this unusual engine and science out a streetable combination. "Chuck had an idea of what he wanted, but he left the details to me," Don says. "The engine had to look like it just came out of the crate, yet it had to be a true street performer. This was going to be a challenge with those gigantic intake ports."
Don's approach centered on two critical areas. With 324 cfm of intake airflow, it would be a monumental compromise to achieve the stated goals with just 400 cubes. The answer was to inject a large boost in displacement.
Don decided to substitute the stock crankshaft with a nodular-iron 455 unit with 4.21 inches of stroke. With a 4.13-inch bore, displacement would jump to 451 ci, a much better match for the intake airflow. As the 455 uses 3.25-inch mains and the 400 uses the smaller 3-inch size, the journals were cut to the appropriate size.
Rod journals were also cut from 2.25 to 2.20 inches to make use of readily available big-block Chevy-style aftermarket rods, a fairly common practice. "I would've gone with one of the new forged cranks that have come to the market," Don says. "At the time, though (spring 2007), they were not yet available. In my opinion, the factory crank is better than the current crop of aftermarket cast cranks."
The second part of the equation centered on the camshaft. With those huge ports, anything that could be done to increase mixture velocity would benefit streetability. Don wasn't about to divulge the exact specs of the profile he developed. He did, however, offer some clues. First off, it's a mechanical roller ground by Comp Cams on a custom blank for the unique R/A-V valve placement. "I'll tell you this much: It's a short-duration, high-lift grind," he says. "It has over 0.600-inch lift and 44 degrees of overlap-most cams at this lift usually run about 60 degrees of overlap, so there's a clue there."
The result is a very flexible engine that has a broad powerband. It will rev to 7,000 rpm if called upon to do so, and it has plenty of manifold vacuum to work with the automatic transmission. "The intake manifold and the cam are limiting total power; the intake design is not that good," Don says. "If we were going for maximum power, we'd build a new manifold and use a bigger cam, but that's not what this engine is about."
What is it about? For Chuck, it allows him to take out his historic race car and actually have some fun with it at the local shows and on the street. "I'll do a burnout with it every now and again, and it will hit seven grand," he says. "It also idles so smoothly, like no other Ram Air V I've ever heard. For me, it's the perfect balance."
Follow along as DCI Motorsports assembles a Ram Air V that lives up to the legend.
The piston and rod assembly...
The piston and rod assembly is a fairly common combination of a 6.800-inch, big-block Chevy-style Eagle rod and a Ross forged piston. Bore size is 4.13 inches, which is 0.020 inch smaller than a standard 455, making the total displacement a slightly smaller 451 ci. This saves cylinder-wall material for future rebuilds.
An obvious difference between...
An obvious difference between a Ram Air V 400 Pontiac block and any other four-bolt block of the era is the ribbing in the lifter bore area. They stabilize the block in two ways: First, the lifter bores are reinforced for use with radical cams, and the other is that the block is more resistant to the stresses that can split it lengthwise down the middle.
The rotating assembly in this...
The rotating assembly in this particular engine is not made up of factory Ram Air V components. A set of 6.8-inch Eagle 4349 H-beam rods and 4.13-inch Ross forged pistons swing on a factory nodular-iron 455 crank, with the mains turned to 3 inches. The rod journals have been turned to a 2.200-inch size.
This custom-ground Comp Cams...
This custom-ground Comp Cams mechanical roller is a proprietary DCI Motorsports grind; the specs have not been revealed.
Harland Sharp roller rockers...
Harland Sharp roller rockers are used in this Ram Air V build and feature a 1.73:1 ratio instead of the factory 1.65:1. The Tunnel-Port heads use the same rocker dimensions as other Pontiac V-8s.
This shot shows the relationship...
This shot shows the relationship of the valve- train to the heads. Intake pushrods run through the center of the intake ports. The airfoils move air around the pushrod tubes, helping mixture velocities. Even with this obstruction, the ports were still too large for responsive street performance on a 400.
A deep-groove top pulley helps...
A deep-groove top pulley helps keep belts from flying off at high speeds. This is an essential piece unique to the Ram Air Vs-with a price tag to match.
Owner Chuck Henley (left)...
Owner Chuck Henley (left) assists Don Johnston of DCI Motorsports as he installs the Holley carb to the intake manifold. The engine is finally done.
The completed 451ci Ram Air...
The completed 451ci Ram Air V is a sight to behold. The combination of a numbers-correct exterior with enlarged internals make for an engine that has enough displacement to make use of those huge intake ports at street-rpm levels. Despite urging by the editor of this magazine, owner Chuck Henley has so far resisted putting the engine on a dyno. As a rule, we avoid publishing power estimates in lieu of actual figures, but with no dyno test, we've little choice. Builder Don Johnston at DCI Motorsports believes the engine makes about 525-550 hp. It has seen over 7,000 rpm repeatedly, so Chuck isn't afraid to lay into it on occasion.