Telling the difference between the various SBC heads can be hard if all there is to go on is what they look like. While there are visual cues that can help tell them apart like the fuelie 'double hump' , there are several ways to ID cylinder heads closer than using just visual cues.
The casting number is usually the best thing to use to tell what a cylinder head was originally used on and its potential for performance use. When referring to the different casting numbers of Chevy heads, typically the last three digits are used because in most cases these numbers are not reused. The casting number may be out in the open where it can be easily seen, like the Pontiac V8, or somewhat harder to see but still visible without taking anything off the head, or the number can be under the valve cover or under the head where it's difficult to see without some amount of disassembly.
Like casting numbers, the date code is cast into the head, and may or may not be visible without removing the valve cover. The date code generally has a letter followed by two or three numbers. The letter is the month. The next number or two numbers will be the day of the month. The last number is the last digit of the year.
These are different shapes that are usually found on the end of the heads. Some examples are shown below. The number along with the date code can be used to pinpoint the heads original application fairly closely. Valve sizes 1. Click HERE for sites with information on casting numbers. Through the years, small block Chevy heads have been ID'd by the head's different end casting shapes. They don't usually tell the exact details like valve sizes but are useful for telling at least potentially a performance head from a non performance head.
A casting identifier can differentiate between a large or small combustion chamber volume, also intake port volume, spark plug type gasketed or tapered seat , whether they were used with a certain type of front accessory arrangement short or long water pump for instance. The most recognized end casting identifier of the SBC heads is the "fuelie", "double hump", or "camel hump". It got the name fuelie from the fact that it was used on optional high performance fuel injected SBC engines, mainly installed in the Corvette.
The name fuelie is somewhat of a misnomer, however; the fuelie heads were used on carbureted engines as well. The names "fuelie", "double hump", or "camel hump" comes from the shape of the casting identifier.
These heads were used during the '60s and '70s on various performance engines. Early on, there was much made of the supposed difference in flow between the Vortec heads that came with the hardened exhaust seat inserts as opposed to the heads that had induction hardened seats. This was largely due to an oft-repeated, although incorrect statement made by a car magazine that said in essence the head was to be avoided because of the exhaust seat insert being vastly inferior to the heads with induction hardened exhaust seats.
The pedestals for the rocker shafts were raised up by nearly 0. That means the valves are longer, too.
https://viptarif.ru/wp-content/products/2520.php All of the rest of the VVT applications create EGR by retarding the cam to leave some residual exhaust gas in the cylinders. The VVT motors came with an all new head that incorporated several notable changes. They have a 65cc oval, closed chamber instead of the 85cc HEMI chamber that was used for the early heads, so the compression ratio was increased from 9.
The intake valves are slightly bigger at 2. Both valve stems are longer because the rocker pedestals were moved up higher on the head to make room for the new exhaust ports.
The new, square intake ports flow CFM at 0. The left head is a DE and the right one is a DD casting. Otherwise, the heads are interchangeable. The late, high volume pump, will physically bolt on the early motors, but it was moved out about 0. Keep in mind that it deactivates four cylinders in firing order sequence, with the exhaust valve closed, in about 10 milliseconds when the computer commands MDS.
Looking for casting numbers for a Mopar V8 cylinder head or engine When identifying the block, you want the raised seven-digit number, not. RB/B, LA Cylinder Head Casting Numbers. The casting numbers for most RB, B, LA heads are found in two places. On the underside of the head on an intake.
All of the timing components were revised, too, including the gears, the chain, the tensioner and the guide. The colored links on the original chain were replaced by three laser-etched rectangles on the links that are used to time the gears. And, the front cover that included the cam thrust plate along with a blade-style tensioner and a chain guide has been replaced by three pieces including a separate cam thrust plate, a plastic chain guide and a tensioner with a spring-loaded piston.
You can actually feel the difference when the short runner valve switches over in my pickup truck. When Chrysler updated the Hemi in , they created a state-of-the-art pushrod motor that performs well in all its cars and trucks.
The VVT motors all make over lbs. My crew cab pickup has pulled a 5,pound car trailer down the road at 75 mph without a complaint and it delivered Chrysler has been selling around , trucks a year for some time now, so that means there are a lot of these HEMI motors out there that will end up getting rebuilt sooner or later because the trucks will be worth fixing when they need an engine. Just make sure you figure out which one fits the application before you send it out the door.