We are always looking for new Chevy engine castings numbers. The top head is the 'lower horsepower' version 300hp and under used on 67-68 327 applications with 1. This also applies to our new-generation precision-cast heads. They show the flow with 1. The only way to see a significant increase from the intake in the 0- to 0.
The late 1967 unit has the temperature sending unit boss but is not tapped. The numbers behind the F or T designate the Calendar month and date the engine was produced. The name fuelie is somewhat of a misnomer, however; the fuelie heads were used on carbureted engines as well. In 1971, combustion chambers were increased to 72cc to lower compression ratios, but other specs were generally the same as heads with tall casting marks. This machined flat area has serial numbers stamped into it. This is a simple form that works well and can be done by most machine shops with even the most basic seat-cutting equipment.
Once a cam decision has been made, you will need to establish just what it will take to get that ratio. This offers a distinct advantage if the rest of the port, especially in the guide boss area, is shaped to work in conjunction with a radius design. Note the intake curves of each of these heads, in stock form, are very similar. The flow for both as-cast and basic ported Dart 215 Platinums is at bottom left on page 85. This applies until the valve reaches one quarter of its diameter in lift 0. Valve shrouding caused by the close proximity of the bore walls red shading or the combustion chamber green shading.
Canfield Heads For a 350 or a 383, I have favored the 195-cc version of the two port volumes offered for Canfield heads. This factor is one of those parts compatibility things so often alluded to but rarely defined. For more information on all the heads covered in this chapter go to MotorTecmagazine. The casting number is probably the most significant feature on a cylinder head as it's the hardest to alter. Porting L31 Vortec Heads In the absence of a flow bench, Vortec heads are about the most goof-proof castings to rework and get good results. See Fig 6-10 for the results. There are a lot of little wrinkles and nuances in porting that only experience and frequent use of a flow bench can teach.
Absolutely no porting on the intake runners of the stock iron Q-Jet manifold. Right now we are limiting our listings to Chevy V-8 blocks, cranks and heads. While doing so, pay attention to the pushrod pinch point as this can usefully be widened to bring the minimum port area up a little. Given enough time, I am sure I could have bumped that 363 hp number to 385 or maybe a tad more. The exhaust of the L98 heads, though, is measurably better.
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. If a little luck swung our way we just might pick some functional aftermarket aluminum heads at a rock-bottom price on eBay. Aluminum Heads Without a doubt, there are some really good heads that have become available since 2000. The date code generally has a letter followed by two or three numbers. Most are easy to find once you know where to look.
June 1967 casting dates have been reported for this head. The exhaust is a different matter. Note these ported 230 Darts are not big on shine. To economize on rolls, do essential work first, and if they are not worn out use the rolls to do the finer finishing work. Heavy 20-30 Series truck uses these, mainly. Click for sites with information on casting numbers.
The exit at the manifold face is not a critical area until a refined state of port development is reached. On the flat part of the Distributor Deck you will find a stamped Serial Number. Basic Small-Block Chevy Head Porting The following information on porting deals with 23-degree Chevy heads pretty much across the board. By deliberately reducing the flow efficiency at the seat on the short side, the amount of exhaust exiting here at the mid- and high-lift is reduced so the long side is allowed to work much better. Doing so makes the ports only about 3 to 4 cc more, and you will like what it does to the top-end output. The medium-blue curves are for ports that are to a basic full porting job. Volumes around the 60-cc mark are fine for a sane low-buck street 350 with flattop pistons in flush to the top of the block.
The longest job is carving out the excess material that resides in the bowls and around the base of the intake valve guide bosses. What this means is that the price is the deciding factor when choosing between these brands. Your first job, using a fine round or half-round needle file, is to remove all the sharp edges from around the combustion chambers. The torque curve was very strong right off idle and would have made a great truck motor. If you are looking for heads with a smaller chamber volume, these heads are typically around 58 cc 64, 68, and 76 are common chamber volumes but milling is limited to a flat mill of about 0.
However, the seemingly wide height tolerance just quoted does not mean we can skip the height check or ignore setting it right. Because of the exceptional casting quality coupled with a highly effective design in terms of flow, porting these heads is about as simple as it can get. The red curves here are for stock 186 factory castings. The casting date is usually found near the casting number. The possible Letters for the last ones are explained in the chart below. This situation represents geometric shrouding and assumes that the air flows evenly around the valve.