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Tech Tips | Questions and Answers

426 HEMI and RB/WEDGE engine blocks

All KB® big block Mopar based engine blocks use an identical Heavy Duty casting.

HEMI® and WEDGE cylinder heads have different head bolt patterns, cylinder-head oil-return and coolant hole locations, along with machining for vastly dissimilar pushrod geometry.

STREET blocks are finished to factory OEM HEMI® and WEDGE dimensions.They have standard camshaft, lifter locations, spacing and geometry; and are designed to accept traditional OEM engine accessories (refer to details fitment options for the standard accessories and parts that can be installed).

RACE HEMI®block, based on the identical Heavy-Duty casting and is machined for a .250 in. raised cam location to allow for large stroke crankshaft and rotating assemblies; as well as to make improvements to valve-train geometry and stability. The block is machined for 60mm diameter roller cam bearings (or 65mm diameter Babbitt cam bearings) with lifters spread to 2.00 in. and lifter angle is adjusted to 48 degrees for vastly improved valve train geometry.

RACE WEDGEblock, based on the identical Heavy-Duty casting and is machined for a .250 in. raised cam location to allow for large stroke crankshaft and rotating assemblies. The block is machined for 55mm diameter roller cam bearings (or 60mm diameter Babbitt cam bearings), and retains the factory OEM 1.80 lifter spacing and 45-degree lifter angle.

PRO blocks can be custom ordered to just about any configuration and to accommodate this are only semi-finished. Consult
your dealer to determine your individual specification requirements.

Both Keith Black Street HEMI and Wedge engine blocks will be the right choice for most street and bracket racers. If your engine is going to exceed
4.625 in. stroke (588 cu.in.) the connecting rod big-end to cam lobe clearance can become a potential issue.

All Keith Black Race blocks, with raised cam, eliminate most interference issues.

Differences in rod
materials and/or dimensions dictate that this must always be checked irrespective
of block choice.

Many racers chose the Race block because the raised location provides for the improved performance offered by the much larger cam core. HEMI engines in particular, also benefit from the greatly improved valve train geometry attained with the Race block.

Yes. Click here for the download link of all current part numbers and specifications.

Billet blocks require extensive machining and welding to add coolant capability for street use. This not only becomes cost prohibitive, but can also lead to weld porosity and/or coolant leaks after heat cycles causing engine failure.


Aluminum transfers heat at a significantly higher rate than cast iron.

The Keith Black aluminum block is designed with very generous water jackets, improved water-flow and cooling design features. In virtually every case; the Keith Black aluminum engine block will operate at LESS temperature than a comparable cast iron engine. Read more about the Keith Black HEMI and Wedge block cooling design features and performance here.


If you're experiencing an issue connecting the Beoplay A1 to your device, checkout the documentation and solutions below:

Interference with the Bluetooth signal – Bluetooth operates in the 2402 to 2480 MHz range and may be disturbed by other 2.4 GHz networks (e.g. WiFi routers and networks, wireless keyboards, mouse, etc). Turn off or remove other Bluetooth connections in the surrounding area, then try connecting again. Alternatively, go to another location, such as an elevator or outside, that has less Bluetooth noise from other products to test your connection.

Distance between the E8 and Bluetooth device - Face the front of your product towards the Bluetooth transmitting device (max distance is 10 meters and line-of-sight). Note that the Bluetooth antenna must be in your right earbud.

E8 Bluetooth receiver in the right earbud – If you wear a sports watch (e.g. an Apple watch) on your left wrist and are experiencing dropout issues, we recommended moving the watch to your right wrist.

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