Help me choose the heads for my engine upgrade

sportsroof69 said:

You have that backwards. Twisted wedge heads flow and perform a size up. A TW170 is on par with an AFR185' and a TW185 is on par with an AFR205. This is due to the improved cross section of the head. TWs really shine in the mid lifts, where the valve spends most of its time, and that's what makes them perform so good. On top of that, they come equipped with Ferrea 9000 one piece valves, and good quality valve springs. AFRs have poor hardware. Wen you go to research what I just said, make sure you look at what bore they're flowed on. AFR likes to show theirs on a 4.125" bore because the inline valves do well on big bores. TWs do better than other heads on a standard bore because of the valve location.

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My stuff says something similar, but the only source I have for the 170 is from the Web

You are right, starting at .200 the TW170 has an edge that the 165 doesnt catch until .500 lift where both heads are maxed out

The only problem is, I have seen the AFR 165 on a bench and I haven't seen the 170, and never even considered them until this thread. My only source says a 2.02 valve with the AFR at 1.90, that would explain the low lift flow, and he of course needs to make sure his pistons can handle the extra radial clearance (which I expect they can)

However, to be honest I wasn't looking at the 170, I was looking at the bigger runner heads. Plus, after a 2 sets of the early Trick flow heads I used on SBC and SBFs in the 99-2000 range dropped a valve I stopped using them

I am not sure on the size up comment, an AFR 185 will destroy that TW170 in flow if matched to the correct motor, but hey, the 170 looks like a decent head, I just didn't want him going with a big port volume on a short cammed small displacement motor.

Also although I agree with you that low and mid lift flow is important, it is really only significant on the leading edge of the ramp, the rate of change in the cylinder and effects of overlap all happen when the valve is opening, cylinder fill on the backside of the ramp is pretty minor. Again, according to what I see, you are right, but remember that overlap will be more effective with a smaller runner, not saying 5 cc makes all that much difference, but flow numbers alone don't make a head

I am going from experience and performance I have seen with the AFRs. I still recommend them highly, but I'd love to see a one for one swap, I have seen it with the bigger heads and AFRs were on top, I havent seen it with the smaller heads

We recently spun a 347 with the mildest of cams and an Autolite carb from a 4x4 with 165 heads and it broke 400 hp. Not hero numbers for a car that could handle more cam and intake, but glass smooth idle with very wide LSA cam and short duration, with a 4100 carb and an early Bronco offset air cleaner. but made big block horsepower. The motor was built as a rock crawler, literally idling through most anything without more than a blip of the throttle, but it impressed me and would be a monster in a classic Mustang

I am very happy with the 165s and have seen the 185s do amazing things too.

Like I said, not a Trick flow guy, and old habits are hard to break when you put your name on someone's motor, but I know lots of guys have great luck with them.

sportsroof69 said:

Check out the links I posted while you were typing that. The TW185 will actually outdo the AFR205. AFRs are good castings and on an oversized bore, they would be on an even playing field, but a TW just does better on a stock bore block. And they come with good valves and springs. A big bore block is where the AFRs shine.

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Good stuff and I appreciate the great info. I have to tell you though, I'd still use AFRs from my personal experience and the close numbers, but admit that the TW has a bit of an airflow edge. Some good info from Fordmuscle in the link below for the original poster

http://www.fordmuscle.com/archives/2003/02/afr/index2.php

Like you said though, the TWs do flow well at low to mid lift, 5-7 CFM better along the curve, 5 cfm average, that really equates to 10 hp difference at peak rpm if used to their max advantage, but his setup probably wont pull the peak numbers, so who knows where actual differences will end up. It's amazing to see that using the standard WAG of 2x intake airflow, both heads will support almost 500 hp where the stockers will be lucky to flow enough for a 325 hp motor.



The key here IMHO is that from an airflow perspective, both heads dominate the competition

So I will concede to TW 170 being good heads for the application, but I still really like the AFR, and if valve clearance is any concern, I'd still consider the AFR as being equal.

My427stang said:

I dont agree at all.

Not even the best GT40 variant flows as much as an AFR 165, the 165 flows 250/191 out of the box.

Compared to the Trick flow, to make those numbers, you need a bigger intake port which he wont need or want with the setup he has.

I have seen these 165s do some great things, 185s even better, but you need a motor that wants the larger intake port, his motor will do far better with the fast 165 port

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The engine doesn't know what size of intake valves the heads have. At this level of build, valve size is a moot point. I guess my question would be, why would 165's do "far better" on his engine?

When just comparing the two heads, the Trick Flows are cheaper, have better components and have an improved intake valve location over the inline AFR heads which are for the most part a ported stock head in an aluminum casting.

When comparing cylinder heads, peak flow is just a very, very tiny part of the equation. More important is average flow. If you compare the three heads from .300"-.500" (any lower does not factor into hp and higher lower flows can actually hurt hp/torque and anything above .500" is moot since his engine is not cammed that large) you will find that the Trick Flow averages 229.7cfm while the AFR 165 is 206.0cfm and the AFR 185 is 230.0cfm (data from Stan Weiss head flow http://users.erols.com/srweiss/tablehdc.htm).

This is a comparison between a head with a cast port and two heads that are fully cnc ported. A Trick Flow 170 is going to beat an AFR 165 when compared on the same engine; its been done over and over again. Not really a fair comparison when considering the Trick Flow 170 is actually sized closer to the AFR 185 when comparing intake port dimensions. Trick Flow 170's and AFR 185's are usually very close in terms of performance out of the box when bolted on an engine. It can be seen why when comparing mid-range flow data; they are almost identical. The problem is you are comparing a cast ported head which costs $500 less and comes with better components than a fully cnc ported head. If you were to put that extra $500 into those Trick Flow heads you would have a very serious head that would outperform the 185's hands down.

For this build in all honesty the cylinder heads, while the most important upgrade on an engine in terms of performance are not going to mean much without further upgrades. If you plan to make performance improvements in the future then cylinder head selection is that more important. Personally, its a no-brainer for me when choosing a head for a 302. The Trick Flow 170 is as good as it gets for the money. With very minor cleanup of the intake ports you can really wake these heads up. The AFR heads are just too much money IMO for what you get. Yes they perform well but not when you consider what can be done to the Trick Flow heads with the money you've saved.

It will be important for you to find out what pistons you have, how far they are in the hole and what size valve reliefs they have when you go to install your cylinder heads. Milling the deck of the cylinder heads to get an appropriate compression ratio is going to do about as much for you as improving your cylinder heads.

6t9mach1 said:

The engine doesn't know what size of intake valves the heads have. At this level of build, valve size is a moot point. I guess my question would be, why would 165's do "far better" on his engine?

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Valve size is never a moot point, every characteristic has its place. Curtain area under a valve is especially important mid lift. However, when I said "far better" I didn't realize TW made a 170cc runner. Like I said, my unhappy experience with Trick Flow was earlier when they used to break guides left and right, so I stopped using them. I wouldn't go cheap then with my name on it and they left a bad taste in my mouth. I have seen the 5.0 crowd do OK, but have never seen any of them with high miles, so I'll still wait for the guy that can get 10 years out of them

But back to the port size 165 vs 170, not a huge difference, in either case, the port will be responsive enough for a relatively low rpm, small cid motor. A 185 or bigger would be lazy with his small cid, short cam motor

6t9mach1 said:

When just comparing the two heads, the Trick Flows are cheaper, have better components and have an improved intake valve location over the inline AFR heads which are for the most part a ported stock head in an aluminum casting.

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Cheaper is good, I'll give you that. The AFR is FAR from a stock head, the exhaust flows more than a stock intake. The TW heads are a neat concept and have followers I can see, but MANY people make a lot of power with AFR too. If you like them though, life is good and keep using them, I have no reason to argue with you and at the same time I don't see you guaranteeing anything I build

However, not sure about the component claim, first, rarely does an off the shelf head meet the specs for builds with my name on it, and rarely will an early flat tappet 302 be able to run the springs that come on either the AFR or the TW. I also have no way of verifying the parts are "better" when I haven't seen anything substandard on an AFR head. Run what you want, but I run in circles where AFR is the quality head.

6t9mach1 said:

When comparing cylinder heads, peak flow is just a very, very tiny part of the equation. More important is average flow. If you compare the three heads from .300"-.500" (any lower does not factor into hp and higher lower flows can actually hurt hp/torque and anything above .500" is moot since his engine is not cammed that large) you will find that the Trick Flow averages 229.7cfm while the AFR 165 is 206.0cfm and the AFR 185 is 230.0cfm (data from Stan Weiss head flow Stan Weiss' - Cylinder Head Flow Data at 28 Inches of Water -- DFW / FLW Flow Files for use with Engine Simulation Software).

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This isnt my first rodeo, you are completely ignoring the exhaust side as well as the effects of overlap with a better exhaust port. Not only do I use Stan's site, I have talked to him many times about his numbers and a million other topics and those numbers are not exact, they are supplied by many people on many benches, to include manufacturers.

Hell, my own KC Stage 2 heads on my 489 had a flow sheet that said 330, we flowed them and they wouldn't break 285, sent them back, he claimed they were better and flowed 330 :shrug:, back on the same bench they were 285. In the end we worked them to flow low 320s. benches are ALL over the place and using that website as the only input, whether it be peak flow or average isn't accurate unless they were flowed on the same bench, same air, same inlet design.

Matter of fact, you are falling into your own "flow number" criticism, on a bench, the TWs flow more at various lifts, add a slightly smaller runner and a noticeably better exhaust port on the AFR 165 and you get more authority on the runner during overlap, this isn't measured on a bench.

Proper sizing of the header primary pipe causes what we call "supercharge effect" which actually fills the cylinder due to exhaust gas pulses pulling more in through the intake during overlap. I am not saying that the TW 170 vs AFR 165 is one way or another, but I am saying a head with more exhaust flow will hang on longer at the top of the curve and can make more torque on the way up. No specifics as I said, I haven't used the TW, but academically, there is more than just mid lift flow. I'd have to test both in a specific combo to see if the 170 made more.

If they did though, I promise I'd admit it, I have no loyalty to AFR, I am just very pleased with them out of experience.

6t9mach1 said:

For this build in all honesty the cylinder heads, while the most important upgrade on an engine in terms of performance are not going to mean much without further upgrades. If you plan to make performance improvements in the future then cylinder head selection is that more important. Personally, its a no-brainer for me when choosing a head for a 302. The Trick Flow 170 is as good as it gets for the money. With very minor cleanup of the intake ports you can really wake these heads up. The AFR heads are just too much money IMO for what you get. Yes they perform well but not when you consider what can be done to the Trick Flow heads with the money you've saved.

It will be important for you to find out what pistons you have, how far they are in the hole and what size valve reliefs they have when you go to install your cylinder heads. Milling the deck of the cylinder heads to get an appropriate compression ratio is going to do about as much for you as improving your cylinder heads.

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Even that is ok advice but a bit off, if the pistons are deep in the hole, milling the heads will just make a detonation monster and be limited by fuel, if indeed the pistons are so low that he needs to cut a head, then he has the wrong pistons and should set up for the proper quench, something that will allow more power with less timing and a better burn overall.

Overall though, you can defend your TW heads, I am not fighting you, run them all day long and if they work well for you I will commend you for a great build, but AFRs run real strong and as a guy with a TON of builds under my belt, I like the AFR and I know the guy wont be disappointed.

The truth is, he probably wouldn't be disappointed with Edelbrocks, ANYTHING is going to be much better than the stockers

I really don't want to have, or win, an argument, but I have had very good luck with AFR and still recommend them

But back to the port size 165 vs 170, not a huge difference, in either case, the port will be responsive enough for a relatively low rpm, small cid motor.

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The difference in port sizes is more than what the 5cc difference in volume would make you think. Since the Twisted Wedge has an altered intake valve location its intake runner is about 3/8" shorter then the inline AFR head. A Trick Flow 170cc heads has a cross sectional area closer to that of an AFR 185 head. Really its not a fair comparison when comparing the Trick Flow to the AFR 165; the Trick Flow is a bigger head. The AFR 165 does well for what it is.

The AFR is FAR from a stock head

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Is its valve location different? Is its valve angle different? The AFR head has a stock valve centerline with stock 20* valve angles. Its essentially a stock sbf head that has been ported out and larger valves installed. Comparing a Trick Flow head to an AFR head is like comparing apples to oranges. The Trick Flow head has an altered intake valve location and different valve angles. I will say that the AFR is the king of the hill when it comes to 20*, inline heads, but I see advantages to the Twisted Wedge design.

However, not sure about the component claim,

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Trick Flow heads come with Ferrea valves and ARP rocker studs. It doesn't get much better then that. I'm not sure if AFR switched to ARP studs then or not. I know that there were some issues with AFR studs breaking for a while.

a noticeably better exhaust port on the AFR 165

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How is the 165's exhaust port "noticeably better"

Even that is ok advice but a bit off, if the pistons are deep in the hole, milling the heads will just make a detonation monster and be limited by fuel, if indeed the pistons are so low that he needs to cut a head, then he has the wrong pistons and should set up for the proper quench, something that will allow more power with less timing and a better burn overall.

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No argument here. I was speaking of minor compression ratio changes by milling. Obviously, if the piston is say .030" in the hole you are not going to be able to get your quench right even by playing with gasket thicknesses.

The truth is, he probably wouldn't be disappointed with Edelbrocks, ANYTHING is going to be much better than the stockers

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This is the truth. I just see the AFR heads as overpriced for what you get. The Trick Flow is less expensive and gives more room to grow in the future. With a dual plane intake and a stockish cam the engines not going to be lazy because of the larger intake ports and larger valves.

6t9mach1 said:

The difference in port sizes is more than what the 5cc difference in volume would make you think. Since the Twisted Wedge has an altered intake valve location its intake runner is about 3/8" shorter then the inline AFR head. A Trick Flow 170cc heads has a cross sectional area closer to that of an AFR 185 head. Really its not a fair comparison when comparing the Trick Flow to the AFR 165; the Trick Flow is a bigger head. The AFR 165 does well for what it is.

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I was going to stop responding just because we both have our opinions and aren't going to convince each other, but I cant stop a good debate LOL

6t9mach1 said:

Is its valve location different? Is its valve angle different? The AFR head has a stock valve centerline with stock 20* valve angles. Its essentially a stock sbf head that has been ported out and larger valves installed. Comparing a Trick Flow head to an AFR head is like comparing apples to oranges. The Trick Flow head has an altered intake valve location and different valve angles. I will say that the AFR is the king of the hill when it comes to 20*, inline heads, but I see advantages to the Twisted Wedge design.

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You are right about the TWs being unique, however you'd never port a stock head to what an AFR flows. Its not just a stock head, but yes, it is an inline head like a stocker. Also, for this application, I just dont see him needing more CSA, plus the overall runner length is going to have an absolutely minor change when adding the intake.

6t9mach1 said:

Trick Flow heads come with Ferrea valves and ARP rocker studs. It doesn't get much better then that. I'm not sure if AFR switched to ARP studs then or not. I know that there were some issues with AFR studs breaking for a while.

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I didnt say TWs were substandard but you claimed they were better quality components, so you tell me why better than the AFR?

6t9mach1 said:

How is the 165's exhaust port "noticeably better"

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IF the TW intake port is better by having more average flow and better flow down low, then i guess we have to look at the TW vs AFR exhaust on the same wavelength

-Avg flow is 148.7 to 142.5, with the nod to the AFR
-Peak flow is equal at 189 cfm
-However, at every point along the way up, the AFR beats the TW, in some places up to 8 cfm

That's the same evaluation you gave the TW intake.

scroll to the bottom of the link

Testing the AFR Small Block Ford 165cc Aluminum Cylinder Head - FordMuscle

I agree exhaust flow isn't as important as intake, but, thats why I said the exhaust port is significantly better.

6t9mach1 said:

This is the truth. I just see the AFR heads as overpriced for what you get. The Trick Flow is less expensive and gives more room to grow in the future. With a dual plane intake and a stockish cam the engines not going to be lazy because of the larger intake ports and larger valves.

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They are 260 dollars more. It is true, but I still like AFRs irate:

Well guys, I certainly appreciate the spirit of this discussion and I'm glad it has been civil. I can't tell you how much I'm learning through this debate.

I got to talk to my engine builder today. While he can't say for certain, he is fairly positive he used Silv-o-lite pistons that were probably flat topped...though he says he may have used dished. He couldn't be sure about the pistons being cut with either style but he wouldn't rule it out.

When I mentioned I was looking at using the TW heads he immediately interrupted me and started talking about valve clearance. He has had several customers add TW heads and have clearance issues. Of course, that might have been avoided had they done some research...like I'm attempting to do. On the other hand, he spoke very favorably of putting the AFR 165s on a SB Ford. He couldn't say enough about them.

Now, as much as I like the TWs on paper, I just think it is smart to go with what the guy who built my engine likes. I'll probably never know the difference between the AFRs or TWs for my application anyways.

That link provided above talking about mid-lift airflow was a good read. Of course everything varies on a given day, but I think it shows how close the two heads really are.

Assuming I used the correct criteria, these are the two AFR 165 options I came to on Summit. Please feel free to double check for me. They appear the same except one will accept AIR injection. I'm guessing I don't want those!
http://www.summitracing.com/parts/AFR-1399/
http://www.summitracing.com/parts/AFR-1402/

So, now that it looks like AFR 165s are the new final choice can I get any suggestions for rocker arms, nuts and head bolts? Anything else I should consider purchasing.