Jan 01, 2000 Check out our second part to building our basic budget 360 engine. This time, we're porting smog intake heads to the engine. More details and photos only in Mopar Muscle Magazine. Super Prepped Heads: 6/27/2018 CNC SUPER PREPPED HEAD (updated6/7/12) Mopar Muscle Magazine asked us to send them a tech article on these heads and we thought it would be a good thing to adapt it to our website so that you could see what you will get when you order these heads.
This is the best budget small block Mopar heads that are for sale for the Chrysler L.A engines. They are Edelbrock performer RPM cylinder heads. They’re best suited for engine’s built from 1968 to 1991. They’re currently on sale on Amazon for around $749 each assembled. Prices do vary regularly on Amazon so it pays to check often. There are many aftermarket brands that offer heads for the L.A engine too. For around slightly more money and slightly better performance. For the money and the years that Edelbrock has been around for, we think this is the best option.
Although we do receive a commission from anyone that buys products through our website links on Amazon, the real reason why we recommend buying the heads from Amazon is because they are a highly trusted supplier and ship most of their products world wide. Most of us today have probably bought at least one thing in our lives from Amazon, so it’s highly likely that you had a good experience right through out the buying process. From finding and selecting the product, to making the payment online then receiving the product at your door any where in the world.
The Edelbrock performer RPM small block Mopar cylinder heads come complete, or bare. You can very easily use your stock valve train components from your current cast iron heads if you already have a complete engine. Depending on your budget and how many miles your current engine has done, it’s always a good idea to upgrade the valves, springs, retainers and locks.
NOTE: The valve guides that come fitted into the Eddy heads have the smaller 11/32 inch valve guides in them. If you want to use your current valves and springs, after having the components checked over for equal size and strength, you’ll need to have the valve guides resized to fit the OEM or factory ones. The OEM valve stem size is 3/8 inch.
Buying a set of Mopar heads complete for a few extra dollars is a much better option. It is recommended that you have someone you know or a trusted machine shop, take a look at them before using right out of the box. Just to be sure there are no manufacturers defects. This is really for piece of mind.
We’ve written a full review, about the small block Mopar cylinder heads from Edelbrock, for the L.A engine called, ‘best small bock Mopar heads on a budget build’. You can find more info about the heads as well as a few photo’s and links to the product here https://quartermileaddiction.com/best-small-block-mopar-heads-on-a-budget-build-review/
What Is Cylinder Head Porting?
If you’re building up your engine to be a bit of high performance street or drag racing engine, you’ll want to look at having your cylinder heads ported. So what is cylinder head porting exactly? This is the process of using a small die grinder to smooth out any sharp edges or slag from the production casting. This is to improve air flow. More air flow means more fuel flow for maximum performance. Although you can port heads for fuel economy or a combination of the two. You can find more info here about cylinder head porting https://en.wikipedia.org/wiki/Cylinder_head_porting
For a good street/strip engine this usually involves porting the heads and intake manifold to the intake and exhaust gaskets. Then blending or smoothing out the intake and exhaust ports. If you look inside your small block Mopar heads and intake manifold, you’ll find the the surface area looks a little rough from the casting process. This can easily be felt by running your finger over the surface area.
We’ve included a great video to show you how this can be done. If you have a steady hand and have a small die grinder, you could easily do this yourself if you wanted to. We would recommend that you try your hand on an old pair of cast iron heads and an old cast iron intake manifold first to practise. It would be a good idea to pick up any cracked or junked aluminum head to practice on too. You’ll notice the difference in how easy it is to grind on the alloy over iron. The video below will explain in more detail.
If you’re not feeling confident about doing your own porting on your own heads then we recommend having a machine shop port them for you.
How Much Does It Cost To Machine A Cylinder Head?
The cost can vary depending how far or fast you want to go. By now after watching the video above, you can understand that this kind of work is very time consuming. You can easily spend 3 or 4 hours just porting an intake manifold. You can expect to pay around $60 an hour with a good machine shop.
Prices do vary so it does pay to shop around. Bare in mind though as the old saying goes, ‘you get what you pay for’. Here’s a link to Steve Schmidt Racing just to give you an idea of what can be done and the cost involved to fully port your heads etc. https://www.steveschmidtracing.com/machine-shop
It’s not necessary to have everything done. It really depends on what you want to do with your engine. What is the main purpose. Porting with a CNC machine can cost on average around $2500 or more. Again this depends on the shop and various other factors like the condition of the heads to start with.
Using Valves From Your Iron Small Block Mopar Heads
If for example you bought a set of bare cylinder heads from Edelbrock it is possible and very doable to use your current valves, springs and rockers from your cast iron factory heads. Removing the rocker assembly and valve train is relatively simple. There is a specialized tool you’d need access to or buy, to remove the springs etc. This is called a valve spring compressor tool. You can purchase them from Walmart or even Amazon. Depending on the brand you choose, you can pick one up for around $20 to $60 .
If you do plan on using your valve train assembly it would be a good idea to check the current condition of your valves for leakage, before disassembling your heads. There is a simple leak test that can easily performed to give you an idea of where your at as far as having a good valve seal on the seat of the combustion chamber. Here’s a quick video to show you exactly how easy this is to do.
Assuming there is no leakage. then the next step is to disassemble your cylinder heads. Be sure to check all components for cracks, wear, or even surface roughness of each part. Be sure to clean every component thoroughly before reuse.
Lapping the old valves is not necessary if there was no leakage with your old heads. It would be a good idea to test the compression of the springs while you have them out. You can buy multi purpose tools that both remove the spring and test the springs compression strength as well from either store as mentioned.
Here’s a great resource guide for recommended valve spring tension rates. https://www.forabodiesonly.com/mopar/threads/factory-valve-spring-load-rates.327028/
Note: if valve spring pressure is low or weak, this can cause valve float or miss fire and lead to spring breakage causing engine failure and disaster. If the tension is too high this can cause excessive valve train wear. See the link here for valve spring basics that further explains what can happen at either end of the spring tension scale http://www.laneautomotive.com/lanemobile/techValveSpringBasics.html
Small Block Mopar Heads For Sale Conclusion
As mentioned in our previous article titled best small block Mopar heads, you can also use your stock camshaft, lifters, push rods and head bolts too. See the article for more info about using your stock parts with your new cylinder head swap.
For the price of a complete assembled set of Edelbrock heads, this might be a better option to save you time and the hassle of sorting out the parts off your old heads. You will need the rocker assembly though, or you will have to buy a new set as the heads don’t come with the rocker assembly.
It would be a good idea to at least test for valve leakage just for piece of mind. We recommend either checking over the heads completely yourself or spending a couple hundred dollars or less to have a good machine shop or engine builder to check them out for you. This is cheap insurance against the possibility of any defects that may have occurred from the factory. As you would I’m sure from any manufacturer that you decide to buy from.
Now would be a good idea to upgrade your intake manifold if you currently have a 2bbl. A good dual plane intake should do the trick. A single plane intake manifold is really recommended for drag racing or higher RPM use. This is because low end power is sacrificed for more power in the upper RPM range. Replacing your spark plugs, leads and checking over your distributor, coil and carburettor at this time would be a good idea too.
If you live in a state in the U.S or a part of the world where emissions tests are mandatory, then you’ll really need to research whether or not you can actually use these heads on your small block Mopar Dodge or Plymouth v8 and drive on the street with them. The reason being is there is no heat crossover pipe or heat riser provision on these heads. The only ones I could find from Edelbrck are for any 1967-91 AMX, Javelin or Jeep with either the 343, 360, 390 or 401 AMC v8 engine.
Mopar Head Porting Templates For Microsoft
For more info about the L.A Edelbrock small block Mopar heads for sale and links to Amazon, where you can either purchase or check out the sale price visit the link here https://quartermileaddiction.com/best-small-block-mopar-heads-on-a-budget-build-review/
We hope you have enjoyed this article about small block Mopar heads for sale and have found some useful tips and information to help you with your purchase of some new heads for your car or project. If you have any questions or feedback, please leave a comment in the comment box below.
Mopar Head Porting Service
#9---C.N.C. Super Prepped Heads | 6/27/2018 | ||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||
CNC SUPER PREPPED HEAD (updated6/7/12) Cylinder heads and their modifications are always a hot topic of conversation among gearheads, from rank amateurs to the top of the heap, professionals. Big ports, small ports, high velocity, reversion, C.F.M., F.P.M., etc. are all jargon that needs to be understood to enter into these high tech discussions, however, once into conversations you will likely find lots of disagreement on what is and what is not important. Any engine can benefit from some sort of air flow increase whether it’s a custom high flow valve & seat job on a Resto-Cruiser or a Hot Street car that includes a bowl porting. For the Hot Street and Street/Strip engine on a budget the question is what gives the most bang for the buck? Part of that answer will be how much bang do you want? The cost of ported heads directly relates to how much work is put into the heads along with how productive it is. The most bang for the buck comes from improving the low and mid-lift flow, for many reasons. First of all the price will be lower because of the time it takes to do the job. Any flow increases at low and mid-lift will benefit the total air flow available twice, once when the valve is opening and once more when the valve is closing. Whereas at maximum lift, the valve is only in that position for a short period of time reducing it’s contribution to the total flow. If the possibility exists that the heads may be completely C.N.C. or fully hand ported at a later time, what is done now, if done properly, should not have a negative effect on that later work. We will try to give you some ideas on what to expect from the porting that Hughes Engines calls their CNC SUPER PREPPED HEADS, for small blocks, when applied to the popular Edelbrock aluminum heads. The most important area of the port is the valve seat and the one half inch area before and after the seat. The actual seat, its angles and widths are the most critical areas and receive as much attention during research and development of the ports as the rest of the entire The exhaust seat is a different deal and incorporates some radii’s along with angles. The area below the seat is called the throat and transitions into the bowl. Each of these areas is customized into the seat and eventually into the runner. The area above the seat is blended into the chamber. This blending may include opening the chamber wall to unshroud the valve, especially around the intake valve. Blending may also include laying back the wall of the chamber directly across from the intake valve. All these are dependent on the port, seat, chamber, etc. In some heads these modifications are very productive; others it is a waste of time or can even hurt the air flow and power. Testing is the only way to know. The seat area and valve angles have the greatest effect on the air flow up to about .350” to.400”lift.. The port runner shape, size and finish have little effect up to that point. Above this lift point the port shape & size of the port starts to affect the flow. The seat area, although still effective, is not the major influence on the flow from about .400” lift on up. A major mistake among new or inexperienced engine builders is to look for the maximum air flow at peak lift. What you should be concerned with is the “area under the curve”. One of the things you will learn when porting cylinder heads is that you have trade-offs. You can concentrate on high lift flow at the expense mid-lift flow and vise-versa. You should make a choice that gives you the most area under the curve. This means more flow at each lift point. A port that flows 15CFM more at .600” lift is not nearly as good as one that flows 15 CFM more at .300” lift, especially if you only have .600” lift. In photo 1 we see a stock Edelbrock L.A. and Mopar Performance chamber and valve seats. The small block Edelbrock head flows up to 40 CFM more than the iron L.A. heads like the “X” and “J” that they replace. They have smaller combustion chambers and have a Photo 2 shows the chamber and seats after Hughes Engines newest C.N.C. Super Prep work. The intake seats are a multitude of proprietary angles and widths. The exhaust is based more on radii’s than angles on edges. The reason for the angles on the intake is for more fuel shear and better wet flow characteristics. With the Hughes seat the angle 45 ºactually sets a little proud from the other angles, Photo 3 -vs-photo 4.This helps the wet flow and can be cut when the heads are freshened without altering the seat width. The CNC machined chamber un-shrouds the intake valve increasing the air flow and encourages better wet flow in the chamber. Better wet flow increases power through better burning. Photos 5 &6 shows the before and after pictures of the port opening. The porting work at the gasket is Hughes’ deep port match and is part of the CNC Super Prep work. Chart # 2 shows the out-of-the box air flow on both the intake and exhaust ports. This chart show the air flow on the same flow bench after the seat & port work, and what the chamber work does for you. The flow figures shown are the average of 3 different ports. It is important to note that the heads were flowed on the same bench before and after so the gains are accurate and relative. Chart #2: These were new Edlebrock 60779 (LA) or Mopar P5153849 heads just out of the box. All numbers are checked & corrected @28”.
Notice how the stock intake flow levels off at about .500”. That pattern will continue throughout the other upgrades. To increase the flow above .500” will require the complete port to be opened up. Chart #3 is the same ports on Edlebrock 60779 (LA) or Mopar P5153849 with Hughes Engines CNC super prepped porting modifications.
We also do this same work on the Edelbrock 61779 (Magnum) heads.
On the Exhaust side, the gains are greater at higher lift because the port is considerably shorter. This flow improvement helps to reduce reversion. Reversion is the effect we see at the overlap point when the Intake valve is just opening and the Exhaust valve is just about to close. This is when the exhaust gas can flow up the Intake port, diluting the intake charge. The greater the overlap of both valves the greater the reversion. The art of building engines is filled with trade-offs and overlap is one of them. Let’s talk about the slight flow loss on the Intake from 500” lift. Cylinder head ports are passages with twists, turns and restrictions. As a restriction is removed the flow goes up, but there are still some restrictions left. As the restrictions that effect flow at lower lifts are eliminated, the flow volume increases to a point that pre-existing restrictions that were not problems, now become problems. This causes the flow at high lifts to stagnate somewhat. The ports can be fully C.N.C. ported and 2.08 valves installed which will remove most all of the restrictions and flow a lot more air “for a few more dollars”. So, O.K., how much power are the Hughes C.N.C. Super Prepped heads worth over out of the box heads? This depends on how the engine is built. On a 360 C.I. with a mild cam, good dual plane intake, headers and a true 10.5:1 compression ratio (Aluminum Heads must run more compression the iron heads), C.N.C. Super Prep work might be worth 20 – 30 more HP. On a Hot 408 C.I. or 416 C.I. stroker you might be looking at 30 – 50 more HP.And if you are really power hungry, Hughes can move the intake pushrod over .200” and supply off-set rockers, photo #9. The combustion chamber work will enlarge the chamber volume about 3-4 cc. Normally we will mill the head a few thousandths to return the volume to stock size. These CNC Super Prepped heads work well for hot street applications, all street/strip applications and in a budget oriented strip only application. Contact us for more information. (309) 745-9558 | |||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||