There are lots of folks out there doing machine work and turning wrenches and doing regular rebuilds everyday. However there are only a very few that take rusty iron and turn it into serious horsepower with old school efforts and skills.
VortecPro Performance Engines is located in Colorado Springs, CO and this small business is rolling along from the extra effort and skill that the proprietor (Mark Jones) puts into each and every one of the engines that he builds. Many of the customers of the business place use the engines in vintage Chevelles, Camaros and even some Chevy powered pickups. All the engines built on site are also dyno tested before shipment to customers around the world. Jones is a real stickler for attention to details and goes at it with a vengeance. He says his biggest problem in making his business grow larger has been in getting people that want to work and adhere to the standards that he demands to keep quality control on track. The guy works like a mule in harness and is very reluctant to make changes to his combinations without testing the changes as he has developed his current combinations over a time with plenty of dyno and track testing.
Why take the effort to improve the engine airflow? Because the engine is a self-driven air pump and improvements in airflow provide the capacity to make more power, it is generally worth the effort to improve the overall engine efficiency.
At least one shop has adapted to filling a need for working with Customers to supply engines for a niche in the market. Others might follow, but it is a tough market to crack and it takes a long time to make inroads.
Jones’ VortecPro Performance offers engine packages that he separates into horsepower levels and they are the following configurations. They are listed for displacement and camshaft selection. Of course the pricing varies with the packages but each gets the extra details attended to in order to maintain quality control.
General Engine Package Combinations
(all have ported iron heads)
450Hp, 468ci, 8.5:1 CR, 4900RPM, hydraulic flat tappet cam
500Hp, 468ci, 9.1:1 CR, 5000RPM, hydraulic flat tappet cam
570Hp, 468ci, 9.6:1 CR, 5700RPM, hydraulic flat tappet cam
620Hp, 468ci, 10.5:1 CR, 6000-6100RPM, solid flat tappet cam
650Hp, 496ci, 9.7:1 CR, 5800RPM, hydraulic roller cam
700Hp, 496ci, 10.3:1 CR, 6100RPM, solid roller cam
750Hp, 496ci, 12.5:1 CR, 6500RPM, solid roller cam
Pricing ranges from a low of $4,895 to a high average of $7,500. Aluminum heads and other options are more expensive additions.
Each block gets a fresh bore and is honed with a deck plate. The main bores also get resized and honed to a final dimension that is straight and true. The block is also cut to a specific dimension. The block not only gets cleaned and washed and heated, but also gets a tremendous level of handwork cleaning and prepping the oiling passages before a final pre assembly washing. The handwork includes meticulous attention to detail in all the block preparations and all the fasteners are replaced with those made by ARP. In fact the ARP fasteners are just about the only thing that doesn’t get reworked in some fashion or another.
Sizing the bores of course depends on the pistons chosen for the build package. Most of the engine packages offered from VortecPro use pistons from SpeedPro or JE or Mahle. The lower performance packages use the SpeedPro units.
The piston rings chosen for all of Jones’ engine packages are typically from Total Seal or from Mahle. There are some variations but most are from those manufacturers.
All cylinder heads get the porting treatment and meticulous attention to valve jobs and guide preparations. The chosen cylinder heads are typically cast iron units that are either casting numbers (781 or 049). Lower performance packages use casting number 236 or what is sometimes called “peanut ports”. Some packages can also use aluminum aftermarket heads depending upon the Customer’s requirements. Most of the guys that want old school muscle motors choose to go with the reworked cast iron heads. Jones just doesn’t bolt on anything because he is not wired that way. He tweaks or changes everything except for very few things in the engine. The aftermarket cylinder heads even get the detailed examination and treatment to ensure the concentricity of the seats and the guide fit are within Jones’ required specs. VortecPro also has its own requirement for shaping the seat approach and departure of the airflow into the combustion chamber. He is particular about the combustion chamber shape as well regardless of the compression ratio selected.
The connecting rods that VortecPro uses are varied relative to the engine package. The lower end of the scale of engines offered utilize reworked stock rods that are resized and equipped with ARP bolts. It is common that the higher power engine packages end up using longer than stock length rods. Jones likes to build his engine packages for longevity and the longer rods are easier on the cylinder walls and piston wear as well. The most popular choice for these engines are the rods from Scat (either I beam or H beam designs). Most of the engine packages use the I beam units.
Standard stock stroke crankshafts are used in some of the engine packages while others use a stroker crank purchased from Scat. Some of the higher power combinations typically use a forged 4340 design also from Scat.
The camshafts that are used are dependant on the engine package but normally the selection is a shorter duration than most builders use. Jones’ engine packages use flat tappets, hydraulic rollers, and solid rollers. One of the most popular packages is the one that uses the hydraulic rollers because the user doesn’t have to pull the valve covers to set the valve lash. The shorter cam timing events with the reworked oval port heads provides impressive torque at
low engine speeds and still provides good breathing at high rpm. Most of the engine packages make their power at less than 6000 to 6200rpm. Jones’ uses camshafts from Iskenderian and Comp Cams for the hydraulic roller and solid roller selections and has even used some of the hydraulic flat tappet pieces from Summit. The issue of camshafts is something that Jones is constantly researching and cam selection is typically to strongly compliment the engine’s airflow combination.
Intake Manifold and Carburetor
Normal intake manifolds are the air gap style from Edelbrock. Some packages use stock intake manifolds but they are not very popular. The carburetor selection is typically Holley four barrels but a few customers have requested Quadrajet carburetors because of the stock appearing issue. The most popular selection is of course the Holley carbs. The stock appearing and correct serial numbers crowd chooses the stock manifold and sometimes a Qjet carburetor. Some customers opt for open plenum manifolds and carb spacers. It just depends on the personal requirements and what the Customer wants the combination to “look” like. Jones likes to know his Customer’s interest and skill level so that he can match the new owner with the best suggestions for his application.
Although VortecPro engine packages are offered with a complete carburetor to pan and balancer to flex plate approach, some customers use their existing distributor and carburetor. Jones prefers to supply MSD distributors so that he knows the timing details when it comes off the engine dyno at his place. Most of the combinations offered are sent out with a total advance of 30 to 32 degrees BTDC while the aluminum head combinations see a bit more advance. See the comments in Lessons Learned on this issue.
VortecPro engine packages use oil pans that fit the chassis requirement and even though more power could be the result of full depth and full length pans, most of his customers do not want to modify the chassis cross members. As a result, VortecPro engines typically use specific pans and oil pumps and pickups that will fit in Chevelles, Camaros or pickups. Believe it or not the selection of the valve covers even enters the combination to match various chassis and Customer requirements. The oil pump and pickup both get attention before they are installed. Jones is adamant about the oiling systems components and goes ballistic when one of his Customers sticks an extra couple of quarts in at the advice of “some dude said”. See the comments in Lessons Learned on this issue.
Each engine gets the detailed in-house balance job too. All the 496ci engine combinations get internally balanced while most of the other packages are externally balanced. But again, if a Customer wants something special it is supplied for a price.
Tuning Comments and Power Results
Jones has learned that combinations need to be supplied to his Customers in a conservative tune-up mode. The dyno test session is typically used to verify the combination will produce the numbers it is supposed to and to verify mechanical operation. All the engines’ dyno testing data is on file and typically a dyno sheet is sent with the engine for the Customer to review or use for bragging rites at the local hot dog drive-in. Most of the combinations are targeted to use pump gas. Unfortunately some buyers decide to run pump gas in some of the combinations that have higher compression ratios and that might get ugly when they choose to change a tune-up and listen to “friends” instead of the engine builder.
Some Lessons Learned
As most of you already know, providing machine shop services or building engines all is not gravy for the shop owner. Many Customers have some pre-conceived notions about power, maintenance required and what is required to keep both properly addressed. Re-education is almost always necessary.
Tuning skills of Customers range from non-existent to comfortable with tools and having friends that race to “having a mechanic”. So that is another area of concern when trying to nurse a bit more power out of old school iron.
One of the most common mistakes made in the field of power dreams is when a friend or some other confidant urge the engine owner to “put some timing in it” based on a poorly founded data base or an avid magazine reader. The “he said, they said, we said” comments are also a source for sending the head gaskets into the trash can. Beware of any comment that is prefaced with “everybody knows” or “everybody does that”. The real scary comments typically begin with “lean ‘er out” or “rev it up” and generally come from those that have no responsibility for the dollars involved.
Something as simple as the cooling system on the vehicle can even cause problems. Proper coolant flow through the cylinder heads and block is an imperative to keep from detonation rattling the door off its performance hinges.
One of the funniest stories learned by this author was one about how a guy had overfilled the pan with so much oil that the engine did not idle smoothly and was seriously down on performance. How much overfill? At least 3 or 4 quarts, the guy put in the correct amount after a phone call and his problem was solved.
And of course some might decide to treat the engine like a carnival ride instead of a machine that needs to be respected. Some folks even try and pretend that oil appears magically in the pan. However, more often than not most Customers do pay attention to the instructions so their stuff will last so they can enjoy it.
Jones makes himself available for phone contact to assist with the first running in the Customer’s car or with race track advice.
There are many American muscle cars that are located around the world and so is the Customer base that has received some of these old school iron muscle motors. Camaros and Chevelles in Europe and Australia or New Zealand or Norway and Sweden as well as all over the US, Mexico and Canada? You bet. Seeking horsepower is a common language and experience varies on how to get there.
Dyno Testing Old School Iron for Horsepower
The build-up of a combination as covered in this story of Old Iron and Horsepower is covered in some general specs and the following is what happens when one of the typical combinations is tested on an engine dyno. (Keep in mind the testing was done on 91 octane pump gas purchased at a local “Loaf ’N Jug” convenience store.)
The high performance fuel supply truly fits the description “pump gas”. The 91 octane stuff gets it done. This is just prior to a dyno session.
This particular engine (specs featured at right) is going into a bright red Camaro so the old school iron will make the package a true muscle car and it will not be driven by a kid either. The owner is a middle-aged guy that will get to live one of the dreams of his younger years.n
Harold Bettes is co-author of Dyno Testing and Tuning and author of The Engine Airflow Handbook. Harold has been a mechanical engineer for over 40 years and has been involved in motorsports for more than half a century. Harold Bettes is a recipient of many awards for his contributions in furthering mechanical engineering, the motorsports industry and the aftermarket. Bettes is widely acknowledged for his expertise concerning dynamometer and flow bench applications. Harold is a consultant on test facilities, equipment and high performance engine designs and configurations and his personal contact information is in the black book of many engine developers, and team owners.
For a PDF of this article (complete with photos), go to: