While the crank is internally...
While the crank is internally balanced, JBA used a Performance Products' damper to help keep the larger rotating assembly in balance.
Getting enough air and fuel into a 331 cubic-inch engine would normally require a overly healthy, choppy idle camshaft that might give away the true secret of this stock-looking engine. But with a cylinder block that's set up to use a roller camshaft, J Bittle American's use of a Ford Racing E303 hydraulic roller camshaft and lifters will keep the engine well fed while maintaining a smooth yet performance-like idle. The cam features 220/220 degrees of duration at .050 lift and uses .498/.498-inch of valve lift on a 110-degree lobe separation angle.
The AFR aluminum cylinder heads also received some light porting and port matching, but J Bittle American engine expert J.R. Twedt says that aside from the extra porting, the AFR cylinder head is one of the best performing street heads in the industry and is perfect for this application. Tony Mamo of Air Flow Research concurs and adds that the 165cc heads work well in this application, flowing 250 cfm to make them more than capable of producing power in the mid to high 400 horsepower range. Mamo also suggested that if we wanted to squeeze a bit more out of the engine, the 185cc head might be worth another 30 or more horsepower.
The original 289 never had...
The original 289 never had a roller camshaft. This Ford Racing roller cam and lifters features 220/220-degree duration and .498/.498-inch lift with 110-degree lobe separation angle. This gives our engine a smooth idle while feeding it plenty of air and fuel.
In designing this engine combination, Twedt also decided to use an Edelbrock RPM Air-Gap intake manifold, as it has excellent fuel distribution and runs cooler to provide a more dense air charge with its raised runners and plenum. But while it might be great to show off a set of aluminum aftermarket pieces like these, the goal here was stealth. In this case, the names on both the cylinder heads and intake were machined away. To further add to the engine's stealth, after it was assembled, the team at JBA painted everything Ford black to match the correct engine color for Peck's '65 Mustang Convertible.
A set of 1.6 ratio Comp roller-tip...
A set of 1.6 ratio Comp roller-tip rocker arms will help to reduce friction and provide a few extra horsepower under a pair of factory valve covers.
All J Bittle American Performance...
All J Bittle American Performance engines are blueprinted and built by hand. Each component is carefully measured and all of the clearances are noted and given to the customer to keep on record.
By using the late-model 302...
By using the late-model 302 block, the engine shouldn't have any cooling problems with a 4.030-inch bore.
Big Power, Small Package
Because the engine was to remain as stock-looking as possible, the factory Autolite 4100 carburetor was used during the engine's break-in and initial dyno tests. The Autolite four-barrel carburetor is Peck's original equipment on the '65 Mustang and it was in perfect working condition. Even though the carb is estimated to flow about 450 cfm, it allowed the 331 to crank out nearly 400 horsepower on JBA's DTS engine dyno.
By adding 36 degrees of total advanced timing from the PerTronix electronic distributor and outfitting the Autolite carburetor with 68/78 jets and a 6.5 power valve, the engine managed to achieve 418.5 corrected horsepower at 6,300 rpm and 392.9 corrected lbs. ft, of torque at 4,500 rpms. This stock-looking 289, which originally made 225 horsepower, now packs a big punch that will leave many people wondering how they got beat by a "restored" 289 cubic-inch small-block in a '65 Mustang.
Here you can see how tight...
Here you can see how tight the rotating assembly fits into the block. The ARP connecting rod bolts come close to the cylinder bore, but they don't touch.
The crank counter-weights...
The crank counter-weights also come close to the cylinder walls, but don't touch. This combination eliminates expensive block machining for added clearance.
Because we used a late-model...
Because we used a late-model 302 block, the advantage of a one-piece rear main seal will ensure that there aren't any oil leaks.
Part of the blueprinting is...
Part of the blueprinting is to note all of the clearances. Here you can see where JBA marks them on the block for reference during assembly.
The AFR 165cc aluminum cylinder...
The AFR 165cc aluminum cylinder heads feature 1.900-inch intake and 1.600-inch exhaust valves and a 58cc combustion chamber. Made specifically for small-block Ford 289 and 302 engines, it's an ideal street/performance head that operates up to 6,500 rpms.
The owner wanted to use his...
The owner wanted to use his factory Autolite four-barrel carburetor. As you can see, it's in mint condition and in this case it didn't hinder the full potential of this engine.