HEMI Engine


This browser cannot play the embedded video file.

600 HP, 426 Naturally Aspirated Hemi With Modified Factory Parts $23,800


Flowline Machined TM

When the 5.7 - 6.1 Hemi SRT8 first came out we worked with Chrysler SRT8 engineering as well as with a major Mopar Super Center to develop one of the best Hemi performance platforms available using only modified factory parts.  These engine platforms were analyzed from top to bottom over a period of two years identifying potential, any weakness and solutions to make more power with durability.

Induction development was one major improvement adding over 20% to the flow potential into the engine.  Induction flow was modified and analyzed while attached to the cylinder head as a port extension.   The throttle body size was also analyzed.  Intake manifold to head adapters were also developed to keep the intake charge cooler in order to make more power.  More about this can be found (here...).

.650 lift Dual Springs

Hemi Specific $495 set 

Cylinder head development included a complete work up of both the 5.7 and 6.1 i.e., analyzed, installed, modified and flow tested.  The combustion chamber, both valves and seats were analyzed for shape and size.  Intake valve and seat ranges were tested from 2.055"-2.200".  Exhaust valve and seat ranges were tested from 1.5" -1.7".  6 valve seat angles as well as 4 valve head angles were included.  Valve length is critical and GM valve are not advisable. For performance applications a single groove valve lock is far superior to a factory triple groove rotating lock.  Several competing aftermarket heads were baselined for comparison.  Several intake port shapes were developed for CNC replication.  Certain combinations emerged as the most practical as well as the most economical to utilize.  In the end, a new machining process Trade Named with the US Patent Office as "Flowline Machined" emerged as the best flowing port.  More about cylinder heads can be found (here...).

Maximum factory valve lift is .550.  Valve train improvements were identified including fitment issues.  Concepts like piston to valve clearance, valve length and valve guide stability for maximum performance were explored.  A custom shaft rocker arm system was developed in conjunction with PRW to stabilize the valve train.  A complete custom camshaft line was developed for maximum performance.  Conical and dual racing springs were developed up to .875 lift.  More about camshafts and valve train can be found (here...).

 426 Stroker Assembly

Note- Oilers in place

Factory block castings and machining accuracy were analyzed for modifications.  Hemi block windage creates over pressurization causing extreme blow-by.  We found a significant solution to this problem.  Bore and stroke combinations were analyzed in conjunction with bore sonic thickness for durability.  It is a serious durability risk to try to build more than 426 cubic inches unless you use the shortest stroke possible.  Certain bore and stroke combinations are prone to piston damage due to piston combination instability with tip over causing piston skirt collapse.  Due to piston cooling, oiling and emissions, retaining the piston oiler in a stroker application is extremely important.  We are set up to do this.  We also analyzed related select parts in the block and know what to do about the timing chain, the oil pump and damper.

Along the way we also designed certain help parts like custom stroker windage trays

and custom Cometic gaskets for a proper build.  When it comes to tuning, please do not try to use the factory European based tuning system.  On highly modified Chrysler products, an aftermarket tuning system is the only way to proceed.  This is why the engine in the movie above is sold with an AEM management system tuned and ready to install into your project.  Dyno sheets can be found (here...).   Our knowledge base is why you should choose an RLD Performance engine.

 RLD Performance, P.O. Box 890066, Temecula, CA 92589 (951) 676-4948, 9am-5pm Pacific Standard Time M-F, stan@rldperformance.com