EQ BBC head porting - zero to hero in 12 days - Chevelle Tech
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post #1 of 13 (permalink) Old Mar 21st, 19, 12:35 PM Thread Starter
David
 
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EQ BBC head porting - zero to hero in 12 days

For my porting school the two heads I focus the students on are BBC and SBC Vortec.

Why these two heads? Because they are challenging. A SBC Vortec head is one of the best stock casting torque generators. There are many folk out there porting these Vortec’s in the manner so often shown in YouTube porting videos. Here then is the news you won’t want to hear. You will have made more negative moves than positive! To make the most of these castings you have to know real porting skills. Even more challenging is the porting of BBC heads. Sure some of the castings are so bad even a guess at what shapes are needed works but that plan of action won’t get you very far if the heads are really good to start with.

In my last porting school I used the iron EQ BBC heads as they are really good right out of the box. To improve on these castings would challenge not only the class attendees but also my capability to pass on what it takes to make real gains on an already well-developed head design.

So how good are these EQ heads? Well let’s look at some numbers here. First the valve and port sizes then the peak flow numbers. In. 2.250 Ex. 1.88. In. port volume (good and bad) 320 cc. Ex. port vol 125. In. cfm 388 @ 0.600, Ex. 247 cfm @0.700.

The exhaust is about typical for a good cast head be it aluminum or iron. The intake though is another story. For a genuine 320 cc port it pretty much matches or even outflows most other heads out there CNC ported or not.
Well flow is one thing but do they make power? I can report here that given the right cam and intake combo they perform really well. I have also heard this from several of my engine builder friends so it’s not a fluke by any means.
Most of my students are either high experience engine builders who do this for their own race efforts or professionals looking to beat their competition in whatever field they specialize in. But for this EQ head class I had one guy who, though an experienced engine builder, had no previous porting skills. (I will leave him as anonymous unless he chooses otherwise). With 10 days of intense schooling the ports he generated went 417 with 330 cc intake (good port) and 298 cfm with 1 150 cc ex port – both at 0.800 lift. This was an excellent figure and, if they got no better, shows the EQ heads in a very good light.

A couple of days back I took a look at the heads and realized they were still equipped with 2.25 intakes rather than the preferred 2.3 and neither intake or exhaust seats had been ‘performance’ cut.
So I cut the seats to suit.
As expected, a super trick seat and a bigger valve pulled some extra flow. These EQ heads were now well into the race flow category with a street port volume and so exhibited good port velocity along with the high flow. I have not quite finished detailing them yet but as soon as I do, I will post the final flow figs.

To summarize I can, with almost certainty say that these heads will really deliver the goods.
I realize that as iron heads they carry a 50 lb. weight penalty. That said there are applications where the extra weight is not a real issue. For instance, a 4500 lb. plus truck is not at any real disadvantage with 50 lbs. extra front-end weight as the EQ heads potential will far outweigh the disadvantage. As a competition set of heads there is at least one area where the extra weight would be an advantage – Bonneville!
Engine(s) for a boat would also not be at a disadvantage as the power potential of these heads far outweighs the weight penalty and of course corrosion in salt water would be far less of a problem compared to aluminum.

I would like to dyno these heads but currently I don’t have a suitable BBC mule that would show them off to their best. The kind of spec where their assets would shine would be a big inch motor. That is of at least 496 inches but preferably a 540 or so right up to 632. On a 632 truck or boat motor they would really be in their element.

Pics – port mold – head- flow curves

If anyone here is thinking of buying a big inch BBC where heads like this would be just what is needed I am prepared to give away the cost of the porting time (at least $2000) cutting these heads to the final spec . What do I expect? I am anticipating about 425-430 CFM with the final intake port volume about 340-345 cc. When I am done with the heads (could be another month yet) I am shipping them up to Terry Walters shop in Roanoke ready for use on an appropriate build. Anyone wanting a set of super trick iron heads where the porting is free might want to call Walters Engines on 540-774-8605.
Wait for final flow data soon.


Captions:-
#1 Here is the raw EQ head before being student reworked.

#2 This is the 417 CFM good port. It does not look anything more than a typical ported BBC head but strong results are in the detail.

#3 Port approach to the bowl and reducing the 'bowl shadow' is the key here and it is easiest achieved with the use of smoke tests, velocity probing, flow balls etc.

#4 here is the EQ BBC flow curves both out of the box (thin lines) and student ported(thick lines)

#5 When you know what to look for the SAE discharge co-efficient is a really good guide towards deciding what the next porting move should be.

#6 Here we have the port velocity before and after. Low port velocity is a big problem with many BBC heads. The EQ is better than most and the mods achieved more velocity on the intake but lost it on the xhaust. Was this that bad - take a look at the port energy graph next in line.

#7 Here is the port energy. Notice that although the exhaust port lost velocity the extra flow totally compensated.
If the concept of 'Port Energy' is new to you then maybe we should do a thread on it.
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Last edited by David Vizard; Mar 21st, 19 at 12:51 PM. Reason: text corection
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post #2 of 13 (permalink) Old Mar 21st, 19, 1:05 PM
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Re: EQ BBC head porting - zero to hero in 12 days

David,
Thanks for taking the time to post your findings/results!
I have a pair of 'em that I plan to use on a pump gas 565 with flat tops. I was planning on a simple cleanup only with no porting.
Best I can tell, these are the same as the old Pro Toplines. RHS apparently only casts the aluminum versions and EQ got the cast irons.
I've read a handful of reviews of the aluminum ones and a couple of "experts" claimed that the top of the short turn is too high, causing separation from the short turn surface, resulting in turbulence but only above about 6000rpm on a 540, IIRC. Overall, they receive positive reviews with a lot of folks making good power with them.
I also bought a pair of their "502 replacement" heads. I am a long way from being an expert, but short turns, bowls and chambers are head and shoulders above any GM iron casting I've had my hands on. I plan to use them on a 496. They're supposedly 299cc intake runners, rectangular ports.
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post #3 of 13 (permalink) Old Mar 21st, 19, 3:59 PM
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Gene
 
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Re: EQ BBC head porting - zero to hero in 12 days

I recall when the cam designer Harold Brookshire (RIP) told me to advance the cam to "increase the ram effect" using rect ports on a 427. I 'm going to assume until told otherwise that was an external way to gain " port energy" by varying valve events, while true port energy is in its natural state. Sort of like static and dynamic compression.

It would be a wonderful thread to learn from!

Gene
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post #4 of 13 (permalink) Old Mar 21st, 19, 6:20 PM
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Re: EQ BBC head porting - zero to hero in 12 days

Very nice numbers David, I know there was one site trashing the EQ heads but I look at it this way, you will not know how bad or good something is until you get a head and test it out.
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post #5 of 13 (permalink) Old Mar 21st, 19, 10:14 PM
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Re: EQ BBC head porting - zero to hero in 12 days

I think these SOB's are heavier than Merlins, super thick decks. I bought mine about a year ago when they were going for $800/pair with free shipping. I'm glad to hear that one of the most respected people in the business has good things to say about them. Gary in NY has a good bit of experience with the ProTopline heads, these are the same thing except for the "EQ" over one exhaust port rather than the ProTopline name cast into the valvetrain side of the head. There's a guy named Abbott on SpeedTalk that has a lot of experience with them and really likes them.

Gary Adrian
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post #6 of 13 (permalink) Old Mar 22nd, 19, 11:45 AM Thread Starter
David
 
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Re: EQ BBC head porting - zero to hero in 12 days

Quote:
Originally Posted by Busted Knuckles View Post
I think these SOB's are heavier than Merlins, super thick decks. I bought mine about a year ago when they were going for $800/pair with free shipping. I'm glad to hear that one of the most respected people in the business has good things to say about them. Gary in NY has a good bit of experience with the ProTopline heads, these are the same thing except for the "EQ" over one exhaust port rather than the ProTopline name cast into the valvetrain side of the head. There's a guy named Abbott on SpeedTalk that has a lot of experience with them and really likes them.
Yes Gary,

Mr Abbott has made some supporting comments and I think he would be a great source to talk ro.
Thanks
DV
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post #7 of 13 (permalink) Old Mar 22nd, 19, 4:34 PM
 
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Re: EQ BBC head porting - zero to hero in 12 days

You'll need to go through about 6 to 8 heads before you get a "set". The 2 sets we have had in the shop took a ton of work before "work" could be performed.

Chris Straub
Mfg Performance Parts

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Why is it we never have time or money to do it the right way in the beginning but we always have time and money to do it over again?
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post #8 of 13 (permalink) Old Mar 22nd, 19, 5:51 PM Thread Starter
David
 
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Re: EQ BBC head porting - zero to hero in 12 days

Quote:
Originally Posted by cstraub View Post
You'll need to go through about 6 to 8 heads before you get a "set". The 2 sets we have had in the shop took a ton of work before "work" could be performed.
Chris,

Could you expand on that please - I am getting head shops call and ask what the deal is.
DV
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post #9 of 13 (permalink) Old Mar 22nd, 19, 6:31 PM
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Scott Foxwell
 
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Re: EQ BBC head porting - zero to hero in 12 days

Quote:
Originally Posted by David Vizard View Post
Chris,

Could you expand on that please - I am getting head shops call and ask what the deal is.
DV
Mainly valve job concentricity, but valve job depth and guide clearance were all completely unacceptable. Funny (odd) thing was, the bore in many of the guides themselves were off center by enough to be visible with the naked eye. I'm talking .010-.015" off center. They said "CHE" on them, but I talked to Claud about it and he said no way were there any guides that ever leave his shop with that kind of run-out. My guess is Chinese heads, Chinese counterfeit guides, as well. Valve guide clearance was, on average, over .0025" so replacing a guide meant that you had to move the valve job to the center of the "new" guide. They were a horrible mess, and I had the same luck with RHS aluminum BB Chev heads a few years ago. Those were machined by Royal Oak Boring in MI and even worse. Never again.

FOXWELL MOTORSPORTS
Straub Technologies

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post #10 of 13 (permalink) Old Mar 23rd, 19, 2:32 PM Thread Starter
David
 
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Re: EQ BBC head porting - zero to hero in 12 days

Quote:
Originally Posted by steelcomp View Post
Mainly valve job concentricity, but valve job depth and guide clearance were all completely unacceptable. Funny (odd) thing was, the bore in many of the guides themselves were off center by enough to be visible with the naked eye. I'm talking .010-.015" off center. They said "CHE" on them, but I talked to Claud about it and he said no way were there any guides that ever leave his shop with that kind of run-out. My guess is Chinese heads, Chinese counterfeit guides, as well. Valve guide clearance was, on average, over .0025" so replacing a guide meant that you had to move the valve job to the center of the "new" guide. They were a horrible mess, and I had the same luck with RHS aluminum BB Chev heads a few years ago. Those were machined by Royal Oak Boring in MI and even worse. Never again.
Chris,

My next move will be to check all that. I think the guides must be somewhere near OK because we always had zero leakage on all the cylinders on the flow bench.

thanks for the info - will report back later
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post #11 of 13 (permalink) Old Mar 23rd, 19, 3:35 PM
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Re: EQ BBC head porting - zero to hero in 12 days

The original Pro-Toplines (aluminum's/photo below) are some of the best heads we've ever worked with and have found none of issues mentioned above here, I guess we got all the "good sets" over the years.

We've never produced under 740 Hp on ANY pump gas 540" with a 10:1 C.R. and never a single one under 700# Torque either. Peak HP numbers about 6200 and peak Torque numbers about 4600, these are all on the retro-hyd roller platform!

The "iron" versions (EQ's) have all made just under the 800 HP range but using the solid roller platform, also above 700# Torque. Haven't experienced any issues with these either but have very limited experience with their "iron" line!

The 320 aluminum's (on our Superflow bench) average 375 CFM and 275 CFM respectively @ .700" lift. Absolutely no porting, all are "as-cast" out of the boxes.These are 2.250" intakes and 1.880" exhausts.

We bought so many when the original company went under we still have a bunch on the shelf. These are for "in-house" use only for our own customers, they are not for sale!

Thanks, Gary in N.Y.

P.S. If you look closely at the photo you'll see intake rocker stud "bushings" already installed from the mfr, no helicoils in this location. Almost all our builds with any other BBC brands get these "bushings" put in before the heads ever get installed here! Been doing this procedure for a few years now, makes no difference whether stud-mounted or shaft-mounted rockers are in the program.
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post #12 of 13 (permalink) Old Mar 23rd, 19, 3:39 PM
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Re: EQ BBC head porting - zero to hero in 12 days

Quote:
Originally Posted by David Vizard View Post
Chris,

My next move will be to check all that. I think the guides must be somewhere near OK because we always had zero leakage on all the cylinders on the flow bench.

thanks for the info - will report back later
Scott, not Chris.
Leakage on the flow bench really doesn't tell you much. When you have .0025" guide clearance, a bad valve job (concentricity) will still find it's "center" and can seal but that's not the real issue. Concentricity aside, I won't let a head out of the shop with .0025"+ guide clearance, especially when some are tapered, some hour glass shaped, and basically just garbage. It's not acceptable to me. That means replacing the guide which is no real big deal -unless- the old guide's bore is horribly out of concentricity and the new guide's bore is on-center. Now you have unintentionally imposed valve to seat run-out with the new guide, and the only way to fix that is to re-cut the seat. Re-cutting the seat to clean up .010-.015 run out means burying the valve job that far. That really sucks to have to do to a set of brand new heads. Now you have to go in and blend the valve job in the chamber and -hope- the flow numbers ate still there. Lot of extra work end expense for a new set of heads. JMO.

FOXWELL MOTORSPORTS
Straub Technologies

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post #13 of 13 (permalink) Old Mar 23rd, 19, 8:07 PM
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Re: EQ BBC head porting - zero to hero in 12 days

Pound the guides out, put a new set in, valve job it. Then you'll see why I recently sent a pallet back.
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