Seriously doubt used in any Z28, L79 etc Black Panther , Oct 16, DDDenny , Oct 16, I never said they were - I said they are the equivalent of an , like a is a equivalent of a Tonawanda and Flint used different casting numbers in and The equivalence is: fuelie - Flint , Tonawanda You generally won't find Tonawanda fuelie heads on L79's, Z28's etc as only Flint had the machining equipment for the 2. Also, the same casting mark as an , just presented in the old way, like a is a double hump but done differently to a 's double hump.
Last edited: Oct 17, HK , Oct 17, I am 45 in I was 13 and started working on a farm , one of the old houses sat a mile off the road in its barn yard sat a 68 C or something that size tractors grow and fields need to be bigger I was gave the chore of junking the truck witch had some how took a hard slam on its side. Erik Cochran , Oct 30, I doubt they were the original heads on a truck The heads were for the same application as the fuelies wherever 1.
In this meant the only to get them was the L30, the hp The only commercial application for this engine in was in an El Camino. The trucks used bigger chamber heads with 1.
They generally ran 8. They were called a "high torque ". The hp used dished pistons and a 2BBL carb, the hp was flat tops but with 75cc heads. They had forged crankshafts and heavier duty valves with rotators on them. Rods were 5.
I'll see if I can find the cast number for these truck heads, pretty sure it is , possibly replaced earlier than normal by As in earlier than the normal September year changeover date - reason I say this is some original GM documentation for truck engines show heads with accessory holes in the ends. Last edited: Oct 30, HK , Oct 30, You must log in or sign up to reply here. Show Ignored Content.
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Small Block Chevrolet Cylinder Head casting numbers /minuit10 / corvette /head chevy /corvette l Chevy cylinder head Identification - Small block casting numbers, Big block cylinder head, camel back heads, double hump heads.
No, create an account now. Yes, my password is: Forgot your password? Atomic Industry www. Our Affiliate Link Policy. Twitter Instagram. While introduced on high-performance rectangular port heads, the open combustion chamber was soon being used in common oval port heads to lower the compression ratio for use with unleaded gasoline, and the reduced quench area was found to be helpful in reducing exhaust emissions.
Aluminum heads have two additional threaded bosses under the intake runners for additional clamping and better head gasket retention when used with engine blocks equipped with corresponding bosses in the lifter valley.
At this point, we can start to look at the actual techniques necessary to rework ports and chambers. Casting number identifies Camel Back heads on engines in to GM models. With an appropriate parts combo, they worked well as-cast and especially well after I ported them. Just make sure all holes are properly lined up and drilled in head gaskets to efficiently pass water. All production heads use the same intake and exhaust bolt patterns, which include a bolt-hole between each pair of intake ports.
The only OEM blocks with these bosses were the rare ZL1 aluminum blocks, but many modern aftermarket blocks have this added feature. Mark IV, Gen V and Gen VI heads all have the same head bolt pattern, but they are not interchangeable due to different water jacket cooling passages. All production heads use the same intake and exhaust bolt patterns, which include a bolt-hole between each pair of intake ports. The boss required for this additional bolt-hole intrudes on the port entrance, so it is deleted on most aftermarket heads because it is not necessary for a good gasket seal.
All production big-block heads had an exhaust crossover passage between the two pairs of siamesed intake ports. All OEM big-block heads had an exhaust crossover passage for intake manifold heat and automatic choke operation, as well as supplying exhaust gas for EGR-equipped exhaust gas recirculation vehicles from the early s on. High-performance engine builders try to keep the intake manifold as cool as possible for maximum intake charge density, so performance intake gasket sets usually include metal plates to block off this exhaust crossover passage, and most aftermarket heads delete the exhaust crossover provision entirely.
The smaller-diameter stems not only lighten the valves for better high-RPM performance, but also offer a slight improvement in airflow. OEM intake valve head diameters were either 2. All production heads and most aftermarket heads come with traditional degree valve seats; however, some high-end aftermarket heads are available with degree seats, which offer improved high-lift flow at the expense of some low-lift flow.
However, they are much more than mere copies of the Chevy part, and many offer such advanced features as non-stock valve angles, larger valve head diameters for more flow, more robust valvesprings for high-RPM operation, and your choice of various intake port sizes to match your requirements.
Some offer raised ports, usually by. Photo Courtesy Edelbrock. Note that if you plan to use exhaust headers designed for stock heads in a stock engine compartment, you need to check for possible header interference with raised port heads, or have custom headers made. Typical material specs call for the use of either A or A aluminum alloy, usually hardened to T-6 specs, and most offer beefier construction with thicker-than-stock deck surfaces and port walls, allowing additional modifications by knowledgeable cylinder head specialists. Contact the manufacturer of your choice for more specific information before making your final head selection.
Modern competition heads usually have heart-shaped combustion chambers to minimize chamber volume and increase the quench area. As good as the original Chevy head design was, things really started to heat up when GM engineers got involved in the Pro Stock wars in the s. Because of the Corporate Engine policy, GM competitors were allowed to use any GM family engine in their race cars and the big-block Chevy was obviously better suited to all-out racing than any other GM big-block engine.
Pontiac engineers took advantage of this break to create a head for the Rat motor with a superior port design, shallower valve angles, and smaller, more efficient combustion chambers. The quench or squish area of the cylinder head is the flat surface that hangs over the bore. The Pontiac Super Duty Pro Stock cylinder head PN featured intake ports that were spread apart to even out the flow differential inherent in the original Chevrolet siamesed port design, and the shallow valve angles required substantially raised intake ports to straighten the airflow path from the port entrance to the valve seat.
From there, Oldsmobile engineers took their shot at creating the best possible drag race head, and introduced the Oldsmobile Pro Stock head PN D-shaped exhaust ports decrease the flow differential between the floor and the roof of the exhaust ports, and they help to combat reversion. Not to be forgotten, Chevrolet engineers also developed a spread port head, the Chevy Symmetrical Port Head PN , with similar design parameters: evenly spaced intake ports and shallow valve angles with miniscule combustion chambers.
All spread port big-block Chevy heads require shaft rocker arms because the pushrods must be relocated around the revised intake port location, and the large amount of rocker arm offset eliminates the use of traditional stud-mount rockers. Most accept the original Pontiac-designed eight-bolt valve covers, although the Edelbrock Big Victor head features a unique valve cover bolt pattern to relocate the bolt-hole bosses for improved rocker arm clearance and valvetrain geometry.
This is one of the reasons that fabricated aluminum sheet-metal valve covers are so popular these days—they can be quickly produced one at a time or in relatively small batches to fit whatever bolt pattern you want.
Besides, they look racy! Its impact on the streets and race tracks of America were immediate and blatant. With time, the engine evolved and gained size, making it even better with age. Now, some four decades-plus later, there are a wide range of factory-based and aftermarket options for the legendary big-block Chevy engine.
Which options are best for any specific purpose can be challenging to figure out, but this book makes it easier. In addition to identifying and reviewing all of the factory components, this book also takes a close look at all the major hard parts offered in the high-performance aftermarket.
The trick to building any high-performance engine is to properly team together the proper components, and How to Build Killer Big-Block Chevy Engines shows readers exactly how to do so. Search: Search.
Oval or Rectangular Intake Ports Much has been said about the differences between rectangular ports and oval ports, and the only fact that everyone agrees with is that each design has its own strengths and weaknesses.