Install and First Impressions
Once the dyno testing was complete we moved forward with some necessary upgrades to the drivetrain including a new clutch, a rebuilt transmission, and a new aluminum driveshaft. In anticipation of the 150-mph top speed, we installed a 13-inch disc brake kit from Baer with six piston calipers as well as a rear disc brake kit from Doctor Diff. With the chassis upgrades complete, the car was sent out the door for some quick shakedown runs around town.
Our Victor 340 intake manifold...
Our Victor 340 intake manifold was fully ported by Ryan at Shady Dell Speed Shop. The guys at BLP built us a special road race style 650 double pumper. The throttle bracket and throttle return setup came from Mancini Racing.
A set of Schoenfeld sprint...
A set of Schoenfeld sprint car 1¾-inch headers fit our dyno cell just perfect. We ran a Meziere electric water pump on the dyno to avoid messing with pulleys and belts. The 8.5mm FireCore spark plug wires are from Custom Wire Sets.
The MSD #8504 E-Curve distributor...
The MSD #8504 E-Curve distributor is fantastic to work with. These distributors come with 100 advance curves built in. They also have vacuum advance, an internal rev-limiter, and do not need an external ignition box. The advance curve is changed by rotating switches under the cap.
The engine idles smoothly at 900 rpm due to the low overlap camshaft and the small carburetor, but the airflow capacity of the heads and intake allows it to pull hard past 6,000 rpm. Even with 2.94 gears in the rear, the car went sideways anytime we stomped on the gas. After a few break-in miles on the street, the car headed out to Portland International for a track day. We had a few teething problems at the track with the oiling system so the session ended early, but in the few laps that Tim was out there, he was able to push the car up to about 150 mph on the back straight. The engine was making enough power to push the car hard down the straights, and the brakes were good enough that he could delay his braking points a little further than last season.
Next steps now are to refine the oiling system and to tune the chassis a bit more. This drivetrain with the aluminum heads, lightweight clutch, and aluminum transmission is about 100 pounds lighter than the previous drivetrain. Taking 100 pounds off the nose of the car means that the suspension needs to be tweaked a bit to get the car back into balance. We already have a bunch more parts on order so stay tuned for an update in an upcoming issue. mm
About the Author: Andy Finkbeiner is the author of How to Build Max-Performance Mopar Big Blocks published by CarTech. Andy also owns AR Engineering, a company that specializes in designing and manufacturing parts for Mopar muscle cars.
Our block is modified so oil...
Our block is modified so oil line fittings can be installed directly into the oil passages. This allows us to run a remote filter during dyno testing without having to use a filter adapter. BLP provided the #12 AN fittings used in the block.
After the dyno testing was...
After the dyno testing was complete, we weighed the engine so we could calculate the power to weight ratio. These R3 engine blocks are heavy, but the aluminum heads and lightweight rotating assembly help to keep the weight down. Total weight as pictured was 450 pounds.
Our friends over at Red Line...
Our friends over at Red Line Oil sent us a complete line of their products. We used 75W90 gear oil in the rear end, MTL in the transmission, and Water Wetter in the radiator.
Knowing that we had 500-plus...
Knowing that we had 500-plus ft-lb of torque to handle, we stepped up to a high-quality clutch assembly from Centerforce. This is one of their Light Metal clutches with an aluminum pressure plate and a dual friction disc. The flywheel is a 20-pound billet steel unit from PRW. ARP now has the correct flywheel bolts for Mopar applications.
A spare input shaft was used...
A spare input shaft was used to keep the clutch disc in place while the Centerforce pressure plate was torqued down. The Centerforce design uses weights on the diaphragm fingers for extra clamping force.
After a lot of work, our 427...
After a lot of work, our 427 was ready to drop into the Valiant. Visible in this picture are TTi headers, a custom oil pan from Charlie’s, a QuickTime bellhousing, and the lightweight aluminum transmission case from Passon Performance. The stack of receipts for this drivetrain assembly added up to a little over $20,000.
Once in the car, the 427 was...
Once in the car, the 427 was equipped with a cold air setup, an Accusump, and an early NASCAR style breather system.
After a few shake-down drives...
After a few shake-down drives on the street, the Valiant was ready for a track day. Sitting in the pits the car doesn’t attract a lot of attention, but a few people did notice the 427 emblems on the front fenders. Wheels are 17x9-inch Mustang rims with 275/40-17 tires on all four corners.
With a power to weight ratio...
With a power to weight ratio that is better than a third-generation Viper, this ’68 Valiant really scoots around the track. Tim had the car going 150 mph down the straight within a few laps.