Car Craft Nov07

1970 Hemi Road Runner – Short Fuse
Troy Brumbalow’s Acme-Fortified ’70 Plymouth Road

By: Geoff Stunkard
Photography: Geoff Stunkard
Reprint from

If you are over 40, chances are you are familiar with how the Plymouth Road Runner got its name. Every Saturday, we’d get up and watch Warner Bros.’ rapid little bird outwit the hapless Wile E. Coyote, who seemed to have a bottomless supply of military surplus rockets, bombs, poison bird seed, and anvils from Acme Products. Mr. Coyote never did catch the Road Runner, as his products always seemed to work too well-on himself. Troy Brumbalow loaded up his Road Runner with some high-tech surplus too, and the ol’ Coyote doesn’t have a chance now.

The Road Runner was likely named after some Plymouth marketing guys spent a Saturday morning watching the cartoon, but it became a serious street legend during its initial production run between 1968 and 1974. While 1970 found an array of optional engine possibilities, the Hemi was, as always, the benchmark mill for the “beeper.” When Troy Brumbalow, a 32-year-old homebuilder from Cumming, Georgia, decided that his ’70 Road Runner project could use a few fortifications, the Hemi was where he started.

“I had a ’68 Road Runner, painted red with the ’69-type 6 BBL hood and a 600-horse 440. I’ve also had a couple of ’73 ‘Cudas,” he says. “Plus, I’ve had Camaros and a ’37 Ford street rod, but this is the first time I’ve ever taken a car down to the bare essentials.”

After four years, the Road Runner project ballooned into the piece of art that you see here. The Acme details began with Troy’s cousin Chad Matthews, who did all the lettering and painted a small mural on the dash. The interior was customized with other gizmos and gadgets, including a custom console hosting a B&M shifter. Other interesting touches include the stainless steel dash with a full selection of Auto Meter gauges and a DVD player featuring Road Runner exploits.

No project of this magnitude is accomplished without some help. Troy got his whole family involved in building, painting, and touring the Road Runner to several Mopar shows around the country. The car has already picked up a First Place win in Pro Street at the Carlisle All-Chrysler Nationals.

We saw Troy’s Plymouth just after its debut appearance, and he had not had a chance to get it down the track. The engine is good for 8,000-rpm blasts, but it has not needed to be wound that tight yet. Regardless, we have a feeling that any coyotes slinking around Cummin





Tech Notes
Troy Brumbalow
What: A ’70 Hemi Road Runner that is a little overboard. Which is OK with us.
Where: Cumming, Georgia, which is Uga territory.




Engine: The mill was built by Hensley Racing in Knoxville, Tennessee. Starting with a 4.500-bore Mopar Performance Hemi block, Hensley added a 4.250-stroke Callies crank for 540 inches. The rotator also has Manley rods, and custom Ross pistons that deliver an 8.5:1 compression ratio. Why so low? It’s got a manifold full of BDS 8-71 with twin 850-cfm Mighty Demons. The heads are from Mopar Performance and feed into Hooker Super Comp headers and a set of 3-inch Flowmasters. “We had removed the K-frame, so there were no conventional motor mount locations, and we had changed the configuration of the transmission with the Gear Vendors unit. That means you just have to move everything a little bit this way and a little bit that way before it is right,” says Troy.

Transmission: Local transmission specialist James Kitchens rebuilt the 727 TorqueFlite and added a Cheetah reverse-manual valvebody and a Gear Vendors overdrive unit. “That is supposed to be a bolt-on type of part, but we still had to hammer on the trans tunnel a bit to get it in there. It gives the car a six-speed ratio ranging from the stock 10.0:1 or so in First with the 4.10:1 rear to an overdrive of about 3.20:1 in Third,” says Troy. “It was a job just getting everything to fit; there are no quick answers when you are customizing a car this way.”

We have since learned that it is recommended by Gear Vendors to slot the two holes in the removeable Plymouth crossmember so that the crossmember drops down 1/4 inch and then the tunnel mods are not required. So, we will do that in our new build (the 71 Cuda designed by Pfaff Designs dubbed “FrankenCuda”).

Paint/Body: Of course, there was a question of color. The hue selected was PPG FY1, a blazing yellow that was applied to the cleaned-up metal by Martin Worth of Auto Refinishers in Newnan, Georgia. This one is not going to sneak up on anybody. A fiberglass hood was purchased and cut for the blower.




Suspension: In the rear, a set of Competition Engineering Slide-A-Link bars and drag shocks were added for a bit of traction. In front, the B-Body has a Magnum Force tubular K-frame with coilovers and a power rack-and-pinion steering setup.

Wheels/Tires: A big car looks cool with big wheels and tires-unless they are too big. The front tires are Billet Specialties 17x8s with 245/45R17 Nitto tires. For traction, the Road Runner uses 18×9.5 rears with 305/35R18 Nitto rubber.

Differential: The power is mostly put to the ground using a Dana 60 with 4.10:1 gears and a set of Moser axles.

Interior: The stainless dash, with Auto Meter gauges and a DVD player, was built by Eric Kimbrel. The upholstery is stock.