Another AFR Head

maximos · Sep 28, 2007

So I've decided to go with some AFR 185 heads. Is there anything I need to check in my engine now before I do the swap? Any type of clearance issues I might come across? I have an Edelbrock Performer 5.0. I also plan to use an
E303 cam. Anything I should replace while I'm in there? Thanks in advance guys.

BlownFiveLiter · Sep 28, 2007

You'll absolutely need to check PTV clearance if you use them. The AFR 185 heads come with a 2.02 intake valve, and to my knowledge, the only heads that can get away with that on a stock shortblock are Twisted Wedges because they're a canted valve design, versus the inline valve design of AFR's. If you're comfortable with flycutting your pistons and using clay to check clearance, then the 185's are good to go. If not, you may want to consider using the 165 heads. The 1.90 intake valve in those will clear stock pistons, given you're not using a cam with outrageous lift.

5spd GT · Sep 28, 2007

The AFR heads have a 23*/23* valve angle as opposed to Trickflow's 15*/17* design.

With that being said, the lower angle of the Trickflow's allows the use of a 2.02" intake valve, while the AFR 185's typically can not. An AFR 165 flows very similar to summit's trickflow heads and they use a 1.90" intake valve.

Check with clay is a good way to see if you will have clearance issues.

By the way, the amount of peak lift is one of the last concerns I would worry about when talking about piston to valve clearance issues. The period of overlap is where the clearance issues occur, with to early intake valve openings and late exhaust closings.

maximos · Sep 29, 2007

I'm new to everything from the valve covers down so bear with me please. You're talking about Piston to Valve clearance, what exactly is getting in the way of what? Also, I've always liked Twisted Wedge heads, but I've heard numerous stories of how weak the valvetrain is on them, is there any way to beef it up? Or should it even be a concern if I'm don't plan on putting out more than 500hp give/take when I'm finished?

final5-0 · Sep 29, 2007

maximos said:
I'm new to everything from the valve covers down so bear with me please. You're talking about Piston to Valve clearance, what exactly is getting in the way of what? Also, I've always liked Twisted Wedge heads, but I've heard numerous stories of how weak the valvetrain is on them, is there any way to beef it up? Or should it even be a concern if I'm don't plan on putting out more than 500hp give/take when I'm finished?

Hello

How about being more specific with what you want from your Stang

I looked at your sig and you now got some nice stuff
to build upon

Also ... since you are new to all this
Share what you now understand needs to be done
to do to accomplish your goal of 500 hp

We got some knowledgeable peeps here and they will be more than
willing to give you the benefits of their findings from doing what
you are attempting to do with your Stang

Grady

mojopony · Sep 29, 2007

Is your bottom end stock? The 185's are a little big for a 302. 165's work good on a stock shortblock. I'm not such a big fan of the E cam. It might be good for certain combos, but I prefer a wider LSA.

5spd GT · Sep 29, 2007

maximos said:
I'm new to everything from the valve covers down so bear with me please. You're talking about Piston to Valve clearance, what exactly is getting in the way of what? Also, I've always liked Twisted Wedge heads, but I've heard numerous stories of how weak the valvetrain is on them, is there any way to beef it up? Or should it even be a concern if I'm don't plan on putting out more than 500hp give/take when I'm finished?

Sorry for the confusion...

What ends up happening during the period of overlap, when both the intake and exhaust valve are open, the piston is near the top of it's travel.

As the intake valve opens on a 2.02" valve (like the AFR 185's), the radial (edge) of the valve can touch the piston. This is called piston to valve clearance/interference.

The AFR angle of 23* makes it where the 2.02" over rides the stock valve reliefs in the piston. Summit's TW heads have a 15* angle for the intake valve, so it will slide right down into the valve relief, instead of overriding the valve reliefs.

Aftermarket pistons takes care of these problems with larger/wider valve reliefs

If you are looking at 500 horsepower, I would look into another block. The stock block tends to want to go kaboom around that range.

Do you want to go with a stroked combination or do you want some boost

As for the valvetrain issues, I believe those have all been solved. There are still quite a few people that refuse to run them because of the past. I have seen a couple guys with higher compression with detonation (not good) crack the combustion chambers.

blksn955.o · Sep 29, 2007

I also thought the 185's had an "issue" with the bore size in relation to the valve/valve angle to a stock 4.000 bore.

I would get TFS TW heads and the spring upgrade or AFR 165's if you want an alum head to work well with your stock bottom end.

Grn92LX · Sep 29, 2007

maximos said:
Also, I've always liked Twisted Wedge heads, but I've heard numerous stories of how weak the valvetrain is on them, is there any way to beef it up?

The springs that come on twisted wedge heads are good enough for the typical mild aftermarket cam's (motorsport letter cams, tfs stg 1 ect) Same goes for afr's, edelbrocks.

You can upgrade the valve train to suit your needs for the camshaft youre running and rpm youre spinning. I just had my twisted wedge heads freshened at my machine shop as I managed to break one of my FTI ps3 springs among other things. We upgraded to crane springs, manley titanium retainers and comp cams 10* locks with proper installed height set. I shift my car near 7,000 rpm so I needed to upgrade to titanium. It doesn't sound like you need that.

Zero_chance · Sep 29, 2007

Id just go with the 165s myself. The AFR website has a test between 165s and185s where the two are nearly identical as far as power numbers are concerned. The 185s only put out between 4 and 15 more HP as the revolutions climb. If memory serves me correctly, the 165s peak in the mid 4000 RPM range and the 185s push it into the mid 5000 RPM range. These tests were done on a 347 with a performer rpm II intake and supporting mods. Im on my playstation 3 so I cant link it but its right there in the small block ford magazin articles. Dont forget, with heads, bigger isnt always better. Depends on what your other mods are and / or your ultimate goal for the car. But if you plan on keepin stock pistons, 165s arent a bad choice.

maximos · Sep 29, 2007

When all is said and done, I'd like to have a 331 stroker with a blower on it. I've been speaking with the gentlemen at Brothers Performance and I was told that a "seasoned block", like mine, with a girdle on it should be able to handle what I would like to do. Initially I had planned on going with the 165's but 185's seemed more appropriate for what my goal was.

The setup I would like is as follows:
AFR 185's
Ed Curtis Custom Cam
Edelbrock Performer Intake
Vortech V1 T-Trim Supercharger

Thanks for all your help thus far. Really the only thing that is making me consider all of this now is something that took place during my intake swap last weekend. It's kind of a long story, one I don't wish to relive.

blksn955.o · Sep 30, 2007

I would never run a boosted stroker on a stock block.

mojopony · Sep 30, 2007

blksn955.o said:
I would never run a boosted stroker on a stock block.

Yeah, I'd skip the blower part.

maximos · Sep 30, 2007

Fair enough...The search for a block begins. Any suggestions?

5spd GT · Sep 30, 2007

Yep, a Dart block

final5-0 · Sep 30, 2007

Considering I started with a stock GT Stang

I had nothing but the lowest performing heads, intake, etc when starting
to mod my Stang

I knew I wanted to go NA
and
The application would be using the OEM block for a Street Combo

I saw two main options

1) OEM stuff
2) After market stuff

I had seen the after market stuff out performed the OEM stuff
but
I also saw the gain was usually not more than around 8 to 12%
and
The cost to obtain that last % of power was not the best value around :Word:

I did #1 to start out with self ported E7 heads/intake but bailed out early
as I knew I would want more.

I then went with #2 and things have worked out much
better than I expected

I have since thought about a blower and will do a KB some day

Now after doing all that
and
If I started out all over again from scratch as I did before with the
same OEM block and Street Car application

I'd do the NA combo with ..........
after market parts from the start and totally skip any OEM stuff

however

If I was gonna do a blower ........
I'd do OEM stuff like gt40 heads/intake with the blower

The OEM stuff will make enough power to split the OEM block

Why put expensive after market parts or put a bunch of money
in machine work to stroke the OEM block when .......

As said above ... the less expensive OEM stuff will make big power
with the added air flow from the blower

To me ... It just seems like throwing good money after bad

If you are stock
and
If you KNOW you are gonna go blown

Get the most power for the least amount of dollar spent and you
still will make way more power than the typical NA Street Combo :Word:

Grady

blksn955.o · Sep 30, 2007

Dart sportsman or BOSS 302.

strongest avail. but overkill,
Dart iron eagle or world Man-O-War.

Zero_chance · Sep 30, 2007

I agree with Grady. Unless money is no concern, uber expensive heads arent really a necessity. All the flow numbers for heads are given at atmospheric pressure. With a blower, youre going to be stuffing air in there like its going out of style. Granted, an expensive aluminum head does have better characteristics and would flow more under the same circumstances, but youll still make great power if you went say with GT40Ps or a similar head. I was inthe same train of thought as you until Grady made the same exact point and hes right. I dont race and I dont street race so there was no point in me going for the expensive gear I was originally aiming for. I still plan on going with a Vortech myself but Im probably going to stick with GT40 p heads and a GT40 intake because I like the look of them, I like Ford stuff (bleeds Ford blue), they make good down low torque where it matters to me, and the money I save versus aftermarket stuff can be well used elsewhere. If you search on the GT40 p heads, theres some very good articles on them and flow charts and numbers for people that are running them as cast. I think you might be surprised by what theyre gaining. Now on the other hand, if you plan on racing then like has been said, you might want to have a side account saved up because the stock block will be on borrowed time. It would be kind of self defeating to waste all that money on nice top end stuff and keep the stock block. Kind of like putting a new dress on an old wh@re. Looks great on the outside, but underneath its still and old wh@re...

Another AFR Head

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