A view of the manifold exits shows the extensive widening done to the runners to match the
To feed the newfound cubes in his one-off 361, Buck wasn't shy about adding airflow capacity. The Edelbrock Victor heads come with large raised ports, which Clark Hinkle reworked and fully ported to a variation of the famous Mopar Max Wedge port. A limitation on the port configuration was the requirement to run a two-plane intake manifold to compete in the '12 AMSOIL Engine Masters Challenge. Buck opted for an Edelbrock Performer RPM manifold, since there is no available two-plane Max Wedge intake for the low-deck Mopar. The complication here is that the Max Wedge port window would be too tall to fit within the fingerprint of a standard port intake.
Buck solved the manifold puzzle by raising and widening the port while filling the port floor, essentially making a short, wide port that could be replicated at the manifold. To mate the intake to the raised port location, he fabricated manifold spacers out of oak plywood. The Victor heads feature Edelbrock valves with generous sizing at 2.25/1.81-inch diameter, admittedly crowded in the small bore of the modified 361. Buck tells us, "You have to be really careful with the small bore and the big valve heads. We notched the bores, helping clearance and airflow, and checked the fit very closely." A Holley 1,000-cfm HP-series carb tops it all to provide the mix.
Up front, Buck used a Mopar Performance beltdriven mechanical water pump arrangement, with
To work those big valves in the Edelbrock heads, Buck went with a Competition Cams solid flat tappet. With Mopar's large 0.904-inch tappet diameter, a very fast rate of lift can be designed into the cam profile. As Buck tells us, "These Mopar flat tappets are very fast and perform just about like a roller. I went with a set of Harland Sharp rockers, using a 1.7:1 ratio on the intake and 1.65:1 on the exhaust. I've been using the Harland Sharps for years, and they never give me any trouble. I did turn a set in to rebuild, and when they saw the rockers they told me they must have been built over 20 years ago, and they actually did them for me for free. The cam and rocker give me 0.656-inch lift on the intake and 0.642 on the exhaust, with the duration at 255 degrees intake and 259 on the exhaust (at 0.050). I had some used NASCAR springs in the shop that I put on and they worked out really good."
With the unusual Mopar's internals assembled, the engine was completed for testing with a set of Schoenfeld 17⁄8- to 2-inch headers and an MSD ignition system. Testing at Hinkle Performance showed numbers that were very encouraging, topping the 600hp level with ease. Buck relates, "We did run the engine with a single-plane intake manifold, and that was quite a bit better as far as top end power. The two-plane did make a lot more torque down low and into the midrange." Looking at the numbers, it's hard to reconcile that the basis here is an old Chrysler 361. Topping out with a torque reading of 520 lb-ft and delivering 618 hp at 7,000 rpm, this Mopar oddity proves that innovative thinking and a mastery of machining talent can pull unexpected power from an unlikely source. Really, isn't that what hot rodding is all about?
|ON THE DYNO
|Tested at Hinkle Performance
|BY THE NUMBERS
|412 Mopar Big-Block
||412 cubic inches
||Custom Comp Solid Flat Tappet
|Rocker and ratio
||Harland Sharp 1.7/1.65:1
||BRC 1.1/1.1/3 mm
||OEM Production Mopar 361
||Eagle 6.657 inches
|Intake valve diameter
|Exhaust valve diameter
||Holley 1000 HP
||Schoenfeld 17⁄8- to 2-inch step
Buck custom-fabricated a valley plate to seal the span between the heads. An oil fill was
Exhaust is expelled via a set of Schoenfeld stepped headers with 17⁄8 to 2-inch primary tu
An interesting detail is the oil pan, a full-length unit that is actually an original Chry