Well actually whats known as our big valve head has actually gone away and is replaced with the Premium big valve head since we stopped using the REV valves about 4 months ago. The new Premium Big valve head has the Manley valves with the pro flow shape. Sizes are 2.10"/1.625 for the 6.1 and 2.02/1.575 for the 5.7 head. So were back with the Manley valves and the new Manley valves will be running single groove locks and use the high quality Crower locks and Retainers which blow everything else that I have seen away in quality. Essentially the premium big valve heads heads are the best quality components that I can source with the Manley valves and Crower locks and retainers. If the intended valve lifts are under 0.580 int and 0.566 ex for the 6.1 heads and 0.566/0.566" for the 5.7 heads the base 6.1 springs are the best option as they have sufficient rate for the fast ramp cams that are out and are the most reliable springs out (if it's not broke don't fix it) and I have yet to see a 6.1 spring fail. For higher lifts contact us for the various options in valve springs, locators, seals. Since the Crower and Manley parts are more expensive the price did go up for $1920 exchange on the 5.7 Big valve head to $2075 for the Premium Big valve 5.7 head and $2175 exchange for the Premium Big valve 6.1 head. The stock valve heads are also available with the Crower retainers for $1575 exchange on the stock valve heads 5.7 and $1675 exchange for the 6.1 Premium stock valve heads. I'll follow up with some photos of the new components.
To those who don't know, these are the heads I have and they are GREAT!!! Especially with a big cam under them to move that extra air.
Stu, what’s the difference between the pro flow shape of the Manley valves and the shape of the stock valves?
The pro flow valve is a wasted stem so it's smaller where the air flows around it. The valve angle is changed and it's back cut and swirl polished. The margin is a little thicker. Basically it's more of a performance valve design.
