ACN Wheelie King Dual Port Cylinder Heads, (L7 heads) 44 X 37.5mm Valves, PAIR are based on a brand new Revmaster 049 Aircraft Aluminum Head casting! We have seen output in the 240hp range with perfect tunes, but normally these are good for 210-220 HP. Must have 1 3/4" or larger exhaust! Aircooled.Net has sold our L7 heads for over a decade, and these are now based on an imported casting.
These heads feature a recently developed new head casting, featuring 12mm x 3/4" Reach plugs (which prevents cracks at the plug threads), Hi Chrome Valve Seats, 44 x 37.5mm Stainless Steel Valves, Silicone Bronze Valve Guides, HD Dual Valve Springs, Chromoly Keepers and Retainers, then finished with a top notch valve job.
You absolutely MUST have an exhaust in the 1 3/4 or 1 7/8" primary size to utilize the flow capability of these heads! Failure to heed this advice can result in difficult (IMPOSSIBLE) tuning issues, and likely cylinder head overheating. It also won't make the power you want!
ACN L7s flow over 220cfm on the intakes at .600" lift, and almost 210cfm at .500" Lift! This creates an incredibly wide and strong power band and torque curve that is hard to comprehend! In fact, these L7s are a top shelf cylinder head, laying waste to most "High Performance" cylinder heads available elsewhere. You absolutely MUST have the cam, exhaust, and intake to go along with them. In fact, this head used to cost around $1200/pair, but the CNC porting and chamber work has dropped the price to where it is now!
Dual 2bbls with venturis in the 42-45mm range are best in your carburetion of choice, dual 48s will work best (DRLA, IDF, or IDA)! At the time of order tell us the chamber cc's you desire and we'll get it done!
With these heads we recommend valve lifts in the .550-.600" range, which is where they will perform at their best.