NEW Heavy Duty Replacement Cylinder Heads — OE Fitment, Performance Ready, NO Cores.

For those who keep experiencing those #4 Valve Seats dropping out of your heads. These heavy duty cylinder heads are new, OE‑style replacements engineered for more strength and serviceability. Supplied as stock OE heads as completely ready‑to‑bolt-on assemblies with better castings than OEM. Stop playing with the BIG-Box stores, do it right the first time!
 
For those wanting more, Oh we have MOAR!
Available Option 2 is the addition of Oversized Stainless Steel Valves for the intake and exhaust side with matching stainless steel valve seats for the ultimate in heat durability and performance reliability. Heavy-duty Springs & Retainers, w/Locks (small or big chamber) for proper valve tension and quicker engine responses to throttle input.
 
Taking it further when combined with our optional 1.6:1 (or higher) Roller Rockers kits and for more control, adding our 4.0L OHV 66mm Throttle Body option wakes up your 4.0L OHV with bumps in HP and TQ adding to a NEW dynamic power curve with smoother control and reliability.
 
These can accept significantly larger porting than stock for improved airflow. Choose from stock chambers or small/large chamber options, then add performance upgrades — oversized stainless valves, heavy‑duty springs, retainers, and locks — to match your build.
 
Stage Porting Options 
The intake and exhaust runners can be ported much larger than the original heads. Available for street reliability, forced induction, or high‑compression setups, with Stage #3 offered as a premium street/off-road port when purchased with NEW heads.
 

As is (stock, bare, small or large chamber) per set
These are brand New bare OE heads
 
New heavy duty brand new replacement heads (complete) with valves, springs, retainers, locks (small or big chamber) ready to bolt on.
 
Porting, over-sized stainless steel valves, heavy duty springs, retainers, locks available - for pricing see above links and add to cart.

ADD porting if desired (below). 

STAGE #2:
Focus: More aggressive reshaping, improving short-turn radius, opening chambers, improving valve guide area, and advanced valve seat work.
Goal: Significant airflow gains for street performance, smoother power bands with more torque, and mild off-road racing/spirited driving.
OHV $1,650.00 per set

STAGE #3:
Focus: Our best street porting job,  Major reshaping, fully contouring ports, maximizing volume, and deep optimization for high RPMs.
Goal: Maximum power for dedicated off-road/racing applications, often involving CNC machines for precision.
OHV $2,750.00 per set
 
Porting prices are added on top of the cost of new heads (except with Stage 3+). Each porting stage reflects the real work behind the proven gains — precision equipment time, tooling wear, hours of hand‑grinding and flow‑checking, and the skill it takes to deliver consistent, competitive, industry‑standard results. 
 
This isn’t quick‑cut machine work. It’s controlled craftsmanship backed by quality control, proper measuring, and the small but necessary costs that keep the process tight from shop bench to shipping, these aren’t cosmetic cuts; they’re engineered airflow improvements backed by skilled craftsmanship and strict QC.