EQ Head Power – High $ Power for Low $ Price.
Is it possible to get a set of new heads that can deliver CNC ported performance for about 50 cents on the dollar? I am here to tell you the answer is
most certainly yes. But the trail that lead to this realization and subsequently this feature was long and often arduous.
It all started when Popular Hot Rodding magazine editor Johnny Hunkins called DV for a cam spec for a 350 small block Chevy project engine which, after dyno testing was somewhat aptly named ‘the Sledgehammer’(the story was in the Nov. 2006 edition). The idea behind the build was to see how much power could be found by selecting cost effective parts and just bolting it all together. Being a student at university I can see the worth of that for sure.
Once given the spec of the motor and the head flow curves DV worked up a cam spec on his Cam Master program. Now here’s where there concern started. The engine was to be tested by the good guys at Speed-O-Motive in West Covina California. Speed-O-Motive has a nice DTS dyno setup similar to the one we use. Because of this it appears that a number of local pro engine builders often use such to test their customer’s engines. The fact that a PHR project engine was to be tested sort of drew some attention and when the goal of 400 hp became known the unanimous opinion of the pro audience was that the DV specced cam was not going to cut it – not even closely. The guy writing this up, who is, according to DV, ‘no mean slouch’ when it comes to building hot engines, was Steve Dulcich. Steve called up DV and asked if he wanted to reconsider the cam spec as ‘the guys’ at his end felt it would be good only to 375 horses at best. DV’s response was ‘just install this cam like I said and it will be good for 400 plus horses’. He was so confident the cam specs were on the money he did not even want to waste time debating the issue.
Well, as the story goes, it seems that some of the guys at the Speed-O-Motive end brought their own cams along just to show how much more their spec would make. This 10.5/1 pump gas PHR engine went 445 lbs-ft and 447 hp on DV’s spec cam. The other cams that came to the dyno show quietly disappeared and no more was said! And about now I am going to get to the point of all this.
When Johnny Hunkins called DV to give him the results the first comments made were concerning the heads used. These were from EQ and DV commented there must be more going for these heads than just airflow as he had expected an output of 420 or so hp. That was early 2007 and so began our investigation as to what EQ heads might be able to do for the budget constrained hot rodder.
A call Eric Haugland at EQ’s Las Vegas division (they have one in Las Vegas and one in Chicago) about the heads used on Sledgehammer revealed that EQ had introduced a high-performance/race version of the heads that were, according to Eric – killing the competition in IMCA circle track racing. This head had a 50 cc combustion chamber and was intended to make hp on the cheap. So began a new project – ‘Son of Sledgehammer’ – and guess what – I get to build it!
EQ 23 Heads – Out-of-the-Box
The target for ‘Son of Sledgehammer’ was to use the 50 cc chamber 180 cc port heads but still run the same compression, or there abouts, as Sledgehammer but this time around use a single plane intake and a slightly bigger cam. As for the heads these looked, for the performance buff, some promising pieces right out of the box.
The consensus of expert opinion on these heads were that they had well thought out chambers and ports.
The engine was a relatively simple spec with Comp street spec hydraulic roller, stock crank and rods, KB pistons, Total Seal rings, FelPro gaskets. The dished KB’s and the 50 cc head combo resulted in a 10.3/1 CR.
Well developed port/chamber shaping along with a precision form and a quality finish all contributed toward very positive results with the EQ heads.
The section through the intake port (left) shows how the port floor shaping has deviated from the traditional SB Chevy ‘ski-jump’ form. Getting the compact chamber to measure out at only 50 cc without compromising flow is a delicate balance of reduced volume while minimizing valve shrouding. The most critical part of the chamber with regards to flow (arrowed) is the gap between the edge of the valve and the chamber wall. Too big and the chamber volume increases. Too small and the flow is compromised due to valve shrouding. The EQ heads strike an excellent balance in this respect.
Shown here are all the variations of the SB Chevy offered by EQ.
EQ sells the heads bare and leaves the customer to furnish their own choice of valves. There are several companies out there that produce cost effective valves. We chose to go with Ferrea’s entry level valves as even their least expensive valves are more than up to the job in hand.
Our choice for springs was also not the cheapest out there but certainly worth the little extra involved. For this build we went with Comps 986 spring.
Here the installed spring heights are being checked/set. The stack-up of valve length, seat cut depth, spring pockets etc was very minimal. Typically all valves were within about 0.006 inches. This speaks well not only for the EQ heads but also for the Ferrea valves used.
For induction we initially borrowed a Barry Grant 750 Street Demon off one of our project cars and mounted this on an Edelbrock Super Victor (which in hindsight might have been a little too much manifold). However we did not get to dyno on the BG Demon because it was required for the project car the same day we were supposed to test. Going in we knew this would not be a problem as we could always use one of T&L’s dyno AED Holley carbs to test with and that is exactly what was done. The particular carb used was AED’s entry level 750 HO. The resulting tests showed we had a motor that, on pump gas, would run strong right down to at least 2200 rpm and that is as low as the T&L SuperFlow would pull it. At 2200 rpm the torque was 327 lbs-ft and it hovered around that figure until 2500 where it took off. From 2500 it climbed steadily from around 330 lbs-ft to a solid 440 lbs-ft at 4900 rpm.
The first batch of tests showed a peak of 467 hp but from the curves it looked like the dreaded hydraulic roller lifter collapse was just starting to have some negative effect as the power dropped off very rapidly at 6200 rpm. This prompted us to change the oil to the Ultra Pro Crate Motor/Hydraulic Roller oil (for more info on that click here *
Hydraulic roller race oil - what's it worth???). After the oil change the power remained virtually identical to the Castrol oil previously used until 6300 then it diverged. Peak power went up to 471 hp at 6300 and after peak ‘drop off’ was much less pronounced. This resulted in some 7 hp increase at 6500 and valve crash at 6520 rpm. Idle speed was a steady (lope free) 700 rpm.
When our test engine was rebuilt to test a nitrous kit, pistons and some other hardware we replaced the Comp 986 springs with their LS6 918 beehive spring. In spite of this springs superiority valve crash still happened at precisely 6520 rpm. The damper seen here is a cost cutting item with SFI rating from Professional Products
So what we have here is a totally streetable engine with a stout 440 lbs-ft and a shade over 470 hp with no exotic parts. In fact this engine could be replicated in turn key ready-to-run form for $3075!
Without doubt these heads look like good power producers. I got to talking with one of the cup car engine builders that passes through our shop from time to time and he offered the opinion that given a 12.5/1 CR and a mild race cam this combination would have seen 500 hp.
Here’s our 350 in dyno ready form. Less headers what you see here can be replicated for $3075.
We ran our tests on T&L’s #1 dyno. White walls and a clean floor make this cell very photo friendly. With all the adaptors and fittings readily to hand loading a SB Chevy on the dyno is really a fast op and reflects in the low cost T&L charges for a days dyno testing.
With as good as these heads are in terms of chamber and port shapes it seemed they would be good candidates for a beginner to start to learn the art of porting. Now at first that might seem to be around the wrong way. Why put a rank beginner on a set of highly functional heads – it looks to be a sure way to ruin all that is good about the heads in the first place. When you hang out with as many ProStock and Cup Car porters as I do certain aspects of head porting are brought to your attention. One that comes to mind is that there are, in most instances, two phases to porting. The first is hogging out metal and the second is applying a precision ground form to the now roughly formed hogged out port. Applying that philosophy to the EQ heads we can say that they are not only pre-hogged out when you get them but also all the main elements of the precision forming are already done. A porting exercise here will be more along the lines of applying a precision finishing exercise.
At this point it all starts to look easy but that’s a trap any beginner can fall into. This was to be my first porting exercise and it was to be carried out not on a set of scrap heads but a $490 set of highly functional new castings. Possibly even worse is an audience of guys who can lay claim to having done the heads on Pro Stockers that have set national records for speed and ET. Worse yet guys who have done the heads on Daytona 500 winners. With credentials like that you know these guys have to be good! But let me tell you the life of an apprentice living under a magnifying glass is not all fun –but I did see a way to divest myself of much of the responsibility should things not work out quite as planned. It’s a rather simple move – ask all these experts for their advice and follow it. If the results are not what they expect then they do, in part, share the blame – good move eh!
So I asked. Here, in a nut shell, is what I got from all of them: slim the guide bosses to a minimum, blend in the cast to machined parts of the port and clean up the rest of the surfaces with an 80 grit emery roll. This all sounds too simple to be true. Not one opinion questioned the basic shape of the ports or chambers- rather it was the other way around. More on the lines of universal approval of the raw material we are working with here.
Tools.
First a word of caution here.
Always use safety goggles and a paint mask so you don’t start the process of developing lung destroying silicosis. Now for the porting tools I was advised to use.
Shot of porting stuff. 011
These in fact were all that was required. The 20,000 rpm air grinder was from Harbor Freight and cost $23. Any decent machine tool outlet will have the carbide cutter and the emery rolls and mandrels required. Expect to spend about $60-75 on supplies here but out of a box of 100 80 grit emery rolls you should be left with enough to do at least another pair of heads. You will also need a set of old valves to protect the seats while working in the chambers. To get close to the seats without actually hitting them reshape the heads of a pair of valves as per the drawing.
That is best done on a lathe but, if you have a steady hand it can also be done on an off-hand tool grinder.
Making a Start.
The first move here is to install the seat protecting valves into a chamber and start by doing some minor cutter work to blend out the small step between the seat and the
chamber walls. When I say minor here I mean just that. I took only about 10 minutes on the first chamber and progressively less as I did the other seven. At this point the short mandrel can be used together with an 80 grit emery roll to finish blend the cutter work around the seats into the chamber walls and the chamber walls themselves polished. It is best to have a radius on the end of the emery roll for this job. As a roll is used so it will wear to a radius so a partially use roll is the ticket here.
The next move is to slim down the width of the intake guide bosses using the 3/8ths oval carbide cutter. Evan though the EQ heads are of high nickel iron the carbide will cut fairly fast so it won’t take very long to get the guide boss as slim as it can be. And how slim is that? Slim here means cutting either side of the guide so as to give more room for the air to pass the obstructing guide and to make the guide boss slimmer so as to offer less resistance to the flow. Once the intake guide bosses are slimmed down, and it should only take about ten minutes per port the job of blending an cleaning up can begin. Using the 80 grit emery rolls I blended the bowls into the seats and tidied up the cutter work around the guide bosses. At this point I rotated the head and, with the longer mandrel, proceeded to clean up the rest of the port. The extent of the clean up was not to remove all the original casting finish but to smooth it down to the point where the original casting dimples were still evident but no bumps existed. This does not take long with an 80 grit roll. The finish left is smooth enough for best airflow but not so smooth that it readily promotes fuel rivulets. With some 20 minutes work the intake port is about done. The results were very satisfying. At 250 lift the minor porting delivered 170 cfm (up from 164) and at 700 lift flow was up from 270 to 292 cfm. That I am told by the experts is a very creditable number for a 200 cc port. Incidentally the port volume changes only by 4 cc so you can see the amount of material removed was very minimal.
The exhaust port flow on these EQ heads is all about a smooth passage past the guide boss and refining the form of the short side turn. Remember they are already good as cast with over 190 cfm at 700 lift. For a regular positioned SB Chevy exhaust port you can reckon that 200 cfm at 700 is a minimum target and 210 a good one although experts here will get as high as 230. Our target is to make the most of the good work EQ has already done here and it is quick and easy. It entails just blending away the excess cast iron around the end of the bronze guide then blending the rest of the port into the seat area. Here it should be said that care must be taken not to touch the radius coming off the seat as this is critical to good flow. Also make sure the short side turn is smooth and has no ridges. I was told going in that 200 cfm at 500 lift was a good yardstick to shoot for. On these, the first set of heads I have ever ported, I got 198-199 so I don’t feel that I missed the boat by much. As for flow at 700 this measured out to 212 and that’s a very satisfactory figure for a set of what could well be termed ‘home ported’ heads.
Bigger Intake.
So long as the motor has plenty of compression making power is much more about intake flow than exhaust. There was room for a 2.08 intake valve in these EQ heads and more to the point we had a set of Ferrea valves this size in the shop that had no home. A search through about a hundred different Serdi seat form tools revealed a cutter that looked a good possibility. The form, shown below, was in fact a form typical of Cup Car heads
Starting from top to bottom we have a 15-20 degree top cut that blens into the existing chamber. Next is a 30 degree cut 0.015 wide. Then there is the seat itself which is 45 x 0.060 wide. Below the seat is a radius cut of 0.250. This joins the seat at a 15 degree angle (the start of the radius is at 60 degrees so the join is 15 degrees off tangent from the seat). The radius cut runs out into an 80 degree bottom cut which is blended into the rest of the port.
prior to the move to 50 degree seats some years back. With the tool loaded in the cutter holder I proceeded to get my first lesson on the use of a Serdi seat and guide machine. They may be expensive but they sure do a nice job – but on with the plot. After cutting the seats I carefully blended in the new seat form into both the chamber and the port. I must admit I took my time here as a slip could mean ruining a finished valve seat.
Here is the finished chamber and ports close up. I guess we should have blown of the last of the remaining grinding grit before this pic was shot but, that withstanding, you should be able to see relevant details.
Here is the finished head from the chamber side. I thought the results looked pretty good for a rank beginner!
This shot shows the very basic finish applied to the intake ports. Definitely no big-shine here - just a good ol’ 80 grit clean up.
The same 80 grit finish that got the job done on the intake also served for the exhaust. The next job on this head was to emery off the paint on the header surface.
Back on the flow bench it was all smiles. The results it seemed ranked with some of the best 23 degree CNC ported heads on the market. If we allow a machining charge of $75 to cut the intake seats then, if you hunt around for the best parts prices it looks like a set of heads as I have done here could come in at about $875 or less. Not bad since you can expect the performance of a set of heads of at least $1500 and have the satisfaction of doing them yourself. As for the time involved in porting these heads remember I was a rank beginner at the outset. Still, by the time I had got to the end of this porting exercise I figured I could do a set in a day. My guess is an expert here could probably get a set done in 4-5 hours as there is so little metal removal involved.
Results Inspection.
The above chart shows the flow bench test results of the 180 and 200 cc EQ ports in out-of-the-box form, in ported form with a stock 2.02 intake and ported with a 2.08 intake. We know how effective these heads are out-of-the-box and the next step is to dyno the ported ones. Normally we would have done this on one of our test engines but the only opportunity we have had to date was a nitrous combination that, with a short street cam, made 466 hp and idled like a Cadillac. This setup also, with 150 jets, pumped out 604 hp on the nitrous. The snag here was that the heads were run with a relatively short, low lift, street nitrous cam (wider LCA than non nitrous) so we were not seeing the full potential of the heads. The 350 mule is currently being rebuilt to deal with 8500 rpm. In this form it is hardly a budget spec and is intended to test some serious race parts. So all I can offer here is some opinions, based on the flow figures and results to date, from those experts around me. The consensus of expert opinion here was pretty tight. All agreed that, with a 12/1 CR, 600 plus hp was a totally practical figure from a budget 383 that should not run up a bill of anymore than $3750! I felt pretty good about the EQ heads as a cost effective means of making power but felt some expert opinion here would certainly not hurt. The outcome of showing the results and asking around left me in no doubt that
these heads deserve a GFN 4.75 star rating.
Dusty Kennett