RCS Performance Engineering



CHI 3V246

The RCS/CHI 3V248 Cleveland/Windsor is without a doubt the best Ford S/B head for an OEM production engine. We purchase them in a raw state from CHI and RCS does the rest. RCS CNC's the seats, combustion chambers, and ports that we have developed from a three month R&D program. These heads have a finish intake port volume of only 248 cc's and a minimum cross sectional are of 2.4 sq. inches. They will work on engine sizes from 302 to 470 cubic inches and the only thing that will change is where the finish rpm will be due to the engine size used. Smaller engines will peak at a higher rpm and the larger at a lower, how’s 750hp at 6,400 on pump gas with 11.5-1 CR from a 432. These heads with the matching intake combo will create 125% Volumetric Efficiency creating monster throttle response and torque over 670 ft. lbs. even with an OEM block as we have.

RCS/CHI heads flow a monstrous 400 cfm @.750 to .800 lifts with air speeds that will blow the tires off the competitors. If you want throttle response and power these are the heads to use. From our experience in developing the RCS/CHI Cleveland these combos work just as well with the Windsor blocks or better.

Combustion size is 37.5 cc's which gives the ability for an engine builder to run a multitude of compression ratio combinations. CR can be as low as 9.5 to 1 to 20 to 1 with gasket, piston volume and engine displacement changes. Any combination is possible with any fuel on the market. This makes this the perfect head for engine builders, diverse and simple. Any rocker combo whether stud mount or shaft mount rockers works great with lifts up to .900 can be achieved.

RCS/CHI Heads have a 1.61 flow to volume ratio per CC making them the best option in the industry.

RCS/CHI 3V248 Flow Values

Valve Lift
Intake Flow Exhaust Flow
.300 228 142
.400 293 186
.500 350 217
.600 380 244
.700 397 260
.800 400 272
.900 400 280

Flow values are based on the use of RCS Intake and Exhaust valves.


Intake Valves 2.200 x 5.740
Exhaust Valves 1.600 x 5.5
Combustion Size 37.5 cc's
Int Port Volume 248 cc's
Exh Port Volume 122 cc's
Max Lift Int/Exh .945
Installed Height 2.100
Push Rod 3/8
Rocker Type Stud or Shaft
Stud Girdle Jomar Cleveland
Intake Gasket O'ring or RCS Gasket
Exhaust Header Flange RCS CNCed Flange


This is a dyno run with the RCS/CHI3V248 heads on a 432 EFI Cleveland with 11.5-1 compression on pump gas. The engine made 747Hp @ 6,500 and 657 lbs. torque @ 5,200, at the 2013 Engine Masters.

RCS 432 Ford Cleveland EFI on pump gas

Call for a current cost and possible options and combinations 412-881-1000.

Note: Not all flow benches and engine Dyno's read the same values. Our values are arrived from 30 years of experience and training, using the highest quality testing equipment available. When comparing products the only true test is to put the products to use and in an environment that will demand the maximum performance from those products. When comparing just values you need to understand the true nature of all the workings of a combustion engine. All professional engine builders are opinionated with their beliefs as to how designs and values should be implemented into the combustion engine, but what we all agree on is that total flow values and air velocity are the most important.