PRI 2017: Noonan’s Record-Setting 4.9 Bore Space Billet Hemi

You’re looking at the quickest engine in the history of blown alcohol doorslammer drag racing….or an identical version of it, anyway.


In October, Australian drag racing legend John Zappia drove Noonan Race Engineering’s ‘68 Camaro to an incredible 5.42-second pass at 265 mph at the Virginia Motorsports Park, and it was made possible by Noonan’s new 4.9-inch bore space, all-billet Hemi — one of the company’s many engine development projects brought to life since its founder, Jamie Noonan, moved his operations to the United States from Australia in 2016.

“This is an engine that we designed and built entirely in-house, and there’s nothing stock about it. Everything that we’ve learned from the 4.8 stuff that we’ve run for many years, we analyzed the weakest parts of that and determined how we could make it better and started from scratch,” Jamie Noonan explains. “This was a clean sheet of paper — we weren’t trying to design an engine around components that are off the shelf, but rather, we wanted to make the part as best we can and design everything.”

The 4.8 is a traditional 426 Hemi standard bore center, but what Noonan did was extend the bore centers out, went away from a center thus bearing like a normal Hemi and went with a rear thrust bearing on the crankshaft. The camshaft has been raised up 1.2500-inch from standard, and the lifter spread was increased from 2.000-inch to 3.300-inch; in doing so, it allows Noonan to remove any pushrod bulges out of the port and keep the pushrod angles dead-straight, thus improving pushrod deflection and valve control. Also, because there are no rules on valve location in many venues, Noonan stood the valve angles up 3 degrees, raised the ports up 1/2-inch, and instituted a 70mm camshaft tunnel. Bores measure up to 4.600-inch; the mill you’re looking at is 4.560-inch, bringing it to 520 cubic-inches. With the maximum bore, you can punch it out to 560, but few racing applications would go that large.

The block, cylinder heads, manifold, gear drive, even the valve covers all designed, machined, and finished at Noonan’s facilities.

“We just went all-out on this motor. When we first built it and got it on the dyno, within three pulls it was definitely substantially better than the 4.8 stuff we’d seen. And we haven’t even gotten to the development stage on improving what we first dyno’ed — we haven’t done camshaft testing or anything,” Noonan notes.

Noonan has also launched new 4.8 heads, which cater to the Pro Modified and Alcohol Funny Car racers: a Pro Mod-specific head with NHRA-legal 2.400/1.900 valves (there’s also a spread lifter version available); a turbo version with a .050-inch larger intake valve and matched port, which is legal for turbo Pro Mods; and an alcohol head, which sports a 2.500-inch take valve, down from a typical 2.550, but with a .050 larger exhaust valve. All three heads, naturally, have different ports but the same valve angles.

About the author

Andrew Wolf

Andrew has been involved in motorsports from a very young age. Over the years, he has photographed several major auto racing events, sports, news journalism, portraiture, and everything in between. After working with the Power Automedia staff for some time on a freelance basis, Andrew joined the team in 2010.
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