Guys,

Been reading that the AFR BBC heads may have some issues with rocker arm geometry requiring offset rockers and guide plate massaging to get everything lined up.

Have any of you guys experienced this? im about to order a set... ?????

thanks

jeff

Guys,

Been reading that the AFR BBC heads may have some issues with rocker arm geometry requiring offset rockers and guide plate massaging to get everything lined up.

Have any of you guys experienced this? im about to order a set... ?????

thanks

jeff
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No longer true
It was not geometry, it was an alignment issue & there were problems in some cases where the guideplates needed "massaging" but it has been addressed.
This is one reason you do not want to run any girdle except the AFR one now according to AFR
It may not fit correctly.
I have not seen any issues in the last couple of years that caused any problems.

Just for info, this is not an AFR or BB problem alone. Seen it with a lot of aftermarket small block heads too.

I dunno Mike..maybe we have been awful unlucky. But the 3 sets *our* group has recieved in the last year or two have all had the same issue. The exhausts are fine, but the intakes are all offset. On two of them we did the normal cut and weld of the guideplates. On the other, the owner was a little more detail oriented and he went through the fun of using backset rockers and offset lifters to get them dead perfect. I'm sure he'll post on this thread, but he spent LOTS of time getting them as perfect as possible and obviously picked up measureable lift when he did it.

Of course that's more than most people mess with and you could do the same with other mfg's heads.

AFR's position was to just leave it alone and run it. Obviously they are right, since I'm sure the vast majority of the owners never even look at it and they run just fine.

Tony builds a great flowing head, no doubt and no one is giving them up!! They make the power and we all know that.....but since AFR is the one that drills the holes it seems like they could have fixed this a long time ago. Just a mfg issue that took too long to get around to.

BTW- has anyone played with the Dart adjustable guideplates? They would be a help in situations like this. Now since they make such a thing, it must be an issue with lots of heads. But I CAN say that the last few Brodix I've messed with didn't have the problem.

Also one thing to pay attention to is pushrod clearance. You will find they can rub the head. Sometimes minor..no big deal...to severe in some cases. With folks going back to 7/16" pushrods in some cases, this is going to be a problem with lots of heads.

Mike...is there a casting date on the AFR's? Maybe we can get an idea when they fixed the issue and anyone looking at used heads and stuff might be able to determine if they are going to have issues or not.

Either way jk67ss396- the heads make fantastic power, it's not too hard to fix and you're doing the right thing by asking. You can't go wrong with the AFR's if they fit the rest of your application.

JIM

Hi Jim,
Really?
I was going by what AFR had told me & a couple of recent sets I used stud mount rockers on with no issue to speak of.
These were in the last 4 or so months so could be the change if one was made is more recent than I thought??
Lined up pretty fair compared to a set of 315's I did about 4 years ago, they were real bad, almost to the point of cutting the plates. Not cool :mad:

I have used Shaft rockers on everything else & there are no problems.
Damn stud mount rockers don't belong on these things anyway :D

And excellent point about pushrod clearance, you need to check this especially with the 7/16 stuff & chances are you will be doing some massaging
Like you said not a big deal if you take the time to check before bolting the heads down.
Goes with the territory.

As for using offset stuff, yes if you want the most lift out of a Rat regardless of head you need to get the pushrod as straight as possible & this is not going to happen without offset stuff.
Very few are going to want to spend the money to do this & I would not consider it without shaft rockers.

I had the issue with my 305's, and was able to slightly elongate the guideplate holes and get things decent.
Mine however are 2 years old now......

I will likely switch to the T&D shaft setup over the winter. Mike and my builder have me convinced.

I'd also like to upgrade the valve springs and retainers at the same time....

Ron

I bought a pair of 325cc as cast heads for my BB 496 this summer. On one of the heads, two of the intake rods bind against the head. One of these rods doesn't fit into the lifter cup. Near as I can tell, the rods are clearing the rod guides. It appears to me that the angle of the bore was off a bit. The other rods all fit fine. I'm using comp cams 7/16" rods. AFR sales weasels weren't at all helpful. best they could come up with was make the holes bigger or use 3/8" rods. Not what I wanted to hear after shelling out some rather large $$ for heads and rods.

Trevor Andersen

Hope this helps to stir the puddin' on this issue.

yeah, im looking for the 325 CNC option.... i was thinking of running 7/16" pushrods too....

where did you get them from? they werent "blem" were they?

thanks

I bought a pair of 325cc as cast heads for my BB 496 this summer. On one of the heads, two of the intake rods bind against the head. One of these rods doesn't fit into the lifter cup. Near as I can tell, the rods are clearing the rod guides. It appears to me that the angle of the bore was off a bit. The other rods all fit fine. I'm using comp cams 7/16" rods. AFR sales weasels weren't at all helpful. best they could come up with was make the holes bigger or use 3/8" rods. Not what I wanted to hear after shelling out some rather large $$ for heads and rods.

Trevor Andersen

Hope this helps to stir the puddin' on this issue.
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Are you kidding me??
I cannot believe some of the whinning I hear sometimes :sad:
What exactly did you expect AFR to do?
Or tell you?
What did you want to hear except you would have to clearance the heads for the larger pushrods??

How much aftermarket stuff have you been involved with? Is this the first engine you have done or what?
Did you take the time to read the instructions?
It tells you in very plain English to check the pushrods for clearance before torquing the heads on along with a number of other things.
And this is with 3/8" pushrods.

I know of no aftermarket head that will always accept 7/16" pushrods without clearancing the intake port & very few that will accept 3/8" pushrods every time.
I have used a lot of different heads & I always check clearance before I bolt the head on, it goes with the territory.

This is big & small block, AFR, Dart, Brodix, whatever.

Hell, I have a set of Dart 335's in the shop right now & you think the AFR has clearance issues??
You should see these.
And this is Dart heads on a Dart block.

This is all part of performance engine building & if you are not willing to check & do what is necessary to make aftermarket parts fit you should probably be buying a crate engine,,,
Or possibly a Honda :D

Here's a copy of my response I sent in an email earlier this afternoon responding to his concerns....hopefully this should clear up and clarify everything right from the horse's mouth as they say...

Hello Trevor...

In a nutshell our BBC heads were set-up to take 3/8 pushrods which provide adequate support and work well in most bracket race and Hi Perf street engines. Installing heavier (larger diameter) pushrods in a bolt on style BBC head that normally requires less than a 9.5 inch total length pushrod (or there abouts) may or may not show you a power advantage...valvetrain mass should always be kept as light as possible to get the job done. There are many 3/8 pushrod BBC engines out there with springs approaching 800 pounds of open pressure without failure turning 8000 RPM. A Pro Stock style (Big Chief) head requires the thicker pushrods because of there much longer overall length (11+ inches)...different story with the standard BBC stuff unless your running crazy spring pressures and very high RPM's. With that said, a 7/16 pushrod install is no different than a guy that wants to install a shaftrocker system on one of our BBC heads....in most cases be prepared to modify the head to accept both but of course be careful because you are modifying at your own risk (don’t blow a hole in the pushrod pinch of the intake port). Also, worst case scenario a head can be welded so you don’t have to proceed forward like it’s a life and death type of situation....just remove as little material as possible is my best advice.

Hopefully this email clears up the situation a little better for you but I'm sure you were hoping for a different response.

Regards,
Tony

PS...Our sales "weasels" try to do a good job and most of them are pretty dedicated to trying to help you guys out...some have more experience than others though and when push comes to shove I try to make myself very available to you guys as well. Sorry you were a little disappointed with our original "customer service".


Thanks guys...
Tony M.

I also had to cut and weld the guide plates on my AFR 305's to get the geometry correct. Not a big deal for me to do.

Here's a copy of my response I sent in an email earlier this afternoon responding to his concerns....hopefully this should clear up and clarify everything right from the horse's mouth as they say...



Thanks guys...
Tony M.
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So,,, you are the "weasel" that caused the problem,, now this explains everything,, I should have known,, :D

If I had known that I would have at least expected you to drop everything & rush to his house & fix his problem for him,,,
That is what a nice "weasel" would have done. :p

Oh, btw the new T&D shaft set up with the one pc intake bar bolts to your head without issue at least in the last two instances I have done.
It is a really nice setup.

No problem other than a slight misalignment on one exhuast stem with 7/16" Mantons and Jesel SS rockers. Never tried it with stud mounted rockers.

John

Hi Tony,

A serious question from a satisfied customer: why isn't the AFR head cast w/ more pushrod clearance? It seems to me (and I admit to being largely ignorant to the details of casting and machining processes required to manufacture a finished head) that additional pushrod clearance in the head would be a difficult endeavor? Especially given the wide variety of ratios and rocker systems your customers regularly employ.

Is there some inherent issue w/ supplying these heads w/ additional pushrod clearance?

Again, an honest question from a very satisfied customer.

Thanks,

Mark

One more thing unrelated to pushrod clearance....

We had a few people that had issues with some geometry on the intake side of our BBC line a long time ago after we initially launched the product. At the time it seemed very related to which type of rocker arms were being used. The Crane Gold which we feel is probably one of the more common out in the field worked OK but some others did not.

Long story short is that Engineering moved the intake rocker stud I believe about .040 and while that doesnt sound like alot it improved the geometry considerably making rocker arm choice a lot less sensitive. Note that our original location was very similar to some competitors heads but ultimately the move we made dialed the rocker/geometry situation even better. Those heads that have the different (improved) stud location used to be stamped with an "S" (short for stud shift) on one of the end pads I believe and quite possibly are still stamped that way. Mike (Wolfplace), thats probably why you haven't had any issues with our BBC product in a long time. Any BBC head we have produced for at least two, probably closer to three years, would have the better intake stud location.

Have a good Holiday weekend...

Tony

Thanks Tony...that's good to hear. At least they did something about the issue. It is too bad the Tech guys don't mention any of that when you call them though. We already knew they were in the wrong place, they just denied it. Too bad Mark, Nick and Rick got their hands on the older ones when they ordered them. They would have been right on that edge if there was some stock on the shelves.

Just for reference, this was with Comp. and Crower rockers I think.

The good news as I said, is that once it's fixed, they do make great power!!

Thanks again Tony for coming on here and telling us what's up. It really helps.

JIM