For those of you not familiar with Sonny Leonard, he is a legendary southern engine builder who is well known for his big-cubic-inch nitrous and naturally aspirated engines. When we say big cubic inch, we’re talking 850ci to 950ci. He developed a block that has a 5.3-inch bore spacing. That’s large enough that you can rent space in it during the off season. Big motors need big cylinder heads, and this new offering from Sonny tops anything that we’ve ever seen. 

Here’s a rundown of pertinent information that should leave even the most jaded hot rodder slack-jawed.

• Intake Valve size: Up to 2.75″                         
• Exhaust Valve size: Up to 2.00″
• Intake runner volume: 650cc                                                               
• Exhaust runner volume: 350cc
• Intake flow: 660CFM @ 1.2″ lift
• Exhaust flow: 450CFM @ 1.1″ lift

This head is intended for use on nitrous assisted Pro Mods and was recently used by Ricky Smith to run the quickest nitrous Pro Mod lap of all time. He ran 5.90/240 in testing down in Florida recently.

The price? You have to call Sonny’s for that. If you need to ask, you can’t afford it.

Source — Sonny’s Racing Engines — 5.3 bore spacing wedge head for Pro Mod Racing