The Hemi 99 cylinder head, released in 1999, is an exclusive design from Steve Sanchez and Total Flow Products.  It was an improvement over existing fuel heads and met his goal of advancing fuel racing.  His inspiration for the design came from years of developing – and repairing – other brands of cylinder heads. 

The Hemi 99 places the intake valve in a “friendlier” area of the combustion chamber.  Sanchez's years of repairing Hemi heads revealed a trend of severe exhaust-side valve train (valve, rocker arm, pushrod) abuse.  Opening the valve against tremendous nitro-fueled cylinder pressure was pounding the components beyond their capability.  Experience told Sanchez a revised exhaust port could resolve the problem.  He reshaped the port for maximum efficiency at low lifts.  That, plus an earlier lift, would release cylinder pressure faster and reduce valve train abuse.

By the late 90s, fuel teams had been using the same cam for ten years and through three or four cylinder head designs.  They were in a comfortable "camshaft rut," and wanted a new head design.  After trying the new TFP Hemi 99 head, and finding no immediate results, teams gave up on it.  Their comfortable camshaft was opening the Hemi 99 exhaust valve earlier than its highly efficient port wanted.  This released part of the power charge and lowered its efficiency.  All the Hemi 99 needed was a new cam, which would open the exhaust valve later – a concept foreign and undesirable to the crew chiefs.  The Hemi 99 head was so good, especially on the exhaust side, the old cam no longer worked properly – it opened the exhaust valve way too soon.

It wasn’t until Rich and Cliff Bozzelli swapped the fuel heads on their Top Alcohol Dragster for Hemi 99s that other racers took notice.  It was unheard of for an alcohol car, with big chamber heads, to run with fat head engines.  But the Bozzellis did just that.  In 2002, without racing a full schedule, they finished fifth in NHRA national points.

Hemi 99 heads have been finding their way into other race venues, also.  National Truck Puller Association Hemi 99 competitors, notably Mark Stigge, are realizing significant power and durability advantages over other brand heads. 

• 3.700” height for +.100” deck height drag racing blocks.  Standard height is available for pulling applications
• Machined for dual spark plugs
• Machined for port nozzles
• Four different rocker offsets for two different style shafts
• Steel valve guides with bronze liners
• 45º intake seat angle, 50º exhaust seat angle
• Choice of ductile iron, copper/nickel or copper/beryllium valve seats
• 2.450” intake valve diameter with 11/32” stem.  Note: heads have been tested with 2.520” intake valves and the most radical cam available.  All clearances have room to spare.
• 5.700” or 5.830” intake valve lengths
• Standard 1.950” exhaust valve diameter with 11/32” or 3/8” stems
• 5.120” or 5.150 exhaust valve lengths
• All valve combinations fit 4.187” or larger cylinder bores
• Unique exhaust shoe anchor location virtually eliminates loosening of shoe
• 173cc standard combustion chamber volume, with custom chamber volumes available

The future of Hemi 99 heads?  Steve Sanchez is working on 3.800” tall design.  The goal, again, is to enhance today’s top fuel engines and stir up the competition in nitro drag racing.