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7/22/2019 8:21 PM  #1


Cylinder head shopping - what numbers matter most?

67 Cpe, 289, Summit 4bbl, C4 daily driver... or it was before the engine tore itself up a month ago.

Fast forward to today and the short block with RV cam is ready to go.  One of the heads was checked out as good, but the other needs to be replaced.  So While I'm At It... I'm considering an upgrade to aluminum heads. 

What do i use as my decision making guide?  Intake runner volume, exhaust volume, combustion chamber volume, valve sizes, etc.

Again, its a daily driver, so i'm not looking for tons of power, but I don't trust the old heads, so i want/need a new or rebuild set anyway.... the comfortable budget is $1k.

Opinions & recommendations???


 

 

7/22/2019 8:29 PM  #2


Re: Cylinder head shopping - what numbers matter most?

Boy you're 'gonna get a lot of opinions on this one TKO will have a more in-depth reply than I do, but I'll offer my opinion. If it were me I'd look at a basic set of TFS "Twisted Wedge" small block Ford heads. Something like this https://www.summitracing.com/parts/tfs-51410004-m61/overview/make/ford These have served the 5.0 crowd for years!

*But* having said that there's a lot more information you'll need. What type of pistons will you be running? What type of fuel is available? What are the specs on that cam? From the sounds of it though the 170s should be solid and allow some room to grow if you ever get a bit more fiesty!

 

 

7/22/2019 8:48 PM  #3


Re: Cylinder head shopping - what numbers matter most?

Id second the Twisted Wedge 170 Trick flow heads.

 

7/22/2019 9:15 PM  #4


Re: Cylinder head shopping - what numbers matter most?

I agree with the 170cc intake volume - perfect for your app, but I see a couple of issues. 

Your 289 has 54cc combustion chambers.  The TFS has 61cc chambers.  Even with flat top pistons you will reduce the compression ratio significantly; a lot more if you have dished pistons..  Meaning less power, not more power.

Those 2.02 intake valves are made for high rpm use.  You will lose flow rate at low rpm, and, one more time, lose power.

I'm thinking that a set of GT40 iron heads might do you in better stead.

I can't give you more specifics.  I will let others fill out any other  data.


Original owner - 351w,T-5, 4whl disks, power R&P
 

7/22/2019 9:25 PM  #5


Re: Cylinder head shopping - what numbers matter most?

lowercasesteve wrote:

I agree with the 170cc intake volume - perfect for your app, but I see a couple of issues. 

Your 289 has 54cc combustion chambers.  The TFS has 61cc chambers.  Even with flat top pistons you will reduce the compression ratio significantly; a lot more if you have dished pistons..  Meaning less power, not more power.

Those 2.02 intake valves are made for high rpm use.  You will lose flow rate at low rpm, and, one more time, lose power.

I'm thinking that a set of GT40 iron heads might do you in better stead.

I can't give you more specifics.  I will let others fill out any other  data.

All good points, TFS does offer different combustion chamber sizes. But I didn't want to go in to that until we find out more about the shortblock, specifically the pistons and the cam. Deck height would be good too.
 

 

7/22/2019 9:47 PM  #6


Re: Cylinder head shopping - what numbers matter most?

The original motor was rebuilt in Oct of last year, so this is essentially warranty work.  With the exception of an "RV"cam, the rebuild was to stock specs.

I could just have the shop find & rebuild suitable factory heads.  But, the WYAI disease has entered the situation and while the shop is seeking a suitable set of cast iron heads to rework for me, I figured i'd see what's out there.  if I find something I like, I'd be taking advantage of having someone else do the labor of installation, etc. if I get the parts.

 

     Thread Starter
 

7/22/2019 9:48 PM  #7


Re: Cylinder head shopping - what numbers matter most?

The original motor was rebuilt in Oct of last year, so this is essentially warranty work.  With the exception of an "RV"cam, the rebuild was to stock specs.

I could just have the shop find & rebuild suitable factory heads.  But, the WYAI disease has entered the situation and while the shop is seeking a suitable set of cast iron heads to rework for me, I figured i'd see what's out there.  if I find something I like, I'd be taking advantage of having someone else do the labor of installation, etc. if I get the parts.

 

     Thread Starter
 

7/23/2019 7:38 AM  #8


Re: Cylinder head shopping - what numbers matter most?

cgomate wrote:

The original motor was rebuilt in Oct of last year, so this is essentially warranty work.  With the exception of an "RV"cam, the rebuild was to stock specs.

 

Why is the motor needing to be worked on after recent rebuild??

I don’t know anything about the heads available to you. The guys are right for mentioning how you existing piston and the size of the combustion chamber can effect you compression ratio.
 


John  -- 67 Mustang Coupe 390 5 speed
 

7/23/2019 9:46 AM  #9


Re: Cylinder head shopping - what numbers matter most?

Suspected oiling issue in one of the heads that lead to the #6 exhaust valve breaking off at the stem... parts then dropped into the cyl and punched a hole in the wall.  Bottom line is i'm getting the engine replaced at his cost.  I'm only considering upgrading heads because the engine is already out, short block built and the engine builder would do all the work putting it back together and into the car.

     Thread Starter
 

7/23/2019 9:51 AM  #10


Re: Cylinder head shopping - what numbers matter most?

To maintain as much of the compression ratio as possible, it looks like there are only a couple choices with 58cc combustion chambers.  Flo-Tek @ $800 for a pair, or AFR @ $800 for EACH.

Clearly the AFR's are top notch, but what about the Flo-Tek (203505) heads?  Anyone know anything about these?

     Thread Starter
 

7/23/2019 12:51 PM  #11


Re: Cylinder head shopping - what numbers matter most?

cgomate wrote:

To maintain as much of the compression ratio as possible, it looks like there are only a couple choices with 58cc combustion chambers.  Flo-Tek @ $800 for a pair, or AFR @ $800 for EACH.

Clearly the AFR's are top notch, but what about the Flo-Tek (203505) heads?  Anyone know anything about these?

I've only ever used Ford Motorsport, TFS, and AFR. There's other ways to change up the CC of the head, you could have it surfaced, but that adds cost. You can also look at the compressed thickness of the head gasket and see if there are alternatives. For the $1k range it might be a better bet to search around for a set of used brand name heads. Just make sure the seller will agree to have them checked by your guys or some other way to verify they are good.

On edit: Also thinking about your budget lowercasesteve had a good idea too about the GT40 heads, although it looks like GT40P's might be better https://lmr.com/products/what-are-gt40-heads-mustang
 

Last edited by Raymond_B (7/23/2019 1:00 PM)

 

7/23/2019 4:50 PM  #12


Re: Cylinder head shopping - what numbers matter most?

Here's my advice.
The chamber volume should be your main concern. 58cc or less. Forget about  202 valve size...big runners...you ain't got the "stuff" to use all that.
Think ...Windsor jr. iron heads.(World Product) Get the machinist to mill them down to 54cc or a tad less. Shoot for 9.5:1 cr.
Aluminum heads will need 10.5:1 or a dab MORE . Ain't gonna happen with your stock dished /flat top pistons!  IF you go with the Alum. heads ask the machinist for some Gravy Train because it will be a dog! Just can't get the CR you need with them and stock pistons.
Jus say'in
6sal6


Get busy Liv'in or get busy Die'n....Host of the 2020 Bash at the Beach/The only Bash that got cancelled  )8
 

7/23/2019 6:08 PM  #13


Re: Cylinder head shopping - what numbers matter most?

The more I read, the more i focused on the compression ratio.... decision made,  I will save my $$ and just let the shop finish the rebuild with the cast iron stock heads and get back to enjoying my car.

Besides, the money saved would get me started on an AOD or T5 conversion setting the stage for a X-country test drive... I hear beaches of South Carolina can be nice in the spring...

Thanks to all who chimed in...

     Thread Starter
 

7/23/2019 7:24 PM  #14


Re: Cylinder head shopping - what numbers matter most?

cgomate wrote:

The more I read, the more i focused on the compression ratio.... decision made,  I will save my $$ and just let the shop finish the rebuild with the cast iron stock heads and get back to enjoying my car.

Besides, the money saved would get me started on an AOD or T5 conversion setting the stage for a X-country test drive... I hear beaches of South Carolina can be nice in the spring...

Thanks to all who chimed in...

 


You got that RIGHT!!!!
April is a GREAT time to be at the beach.......April23-24-25
6sal6


Get busy Liv'in or get busy Die'n....Host of the 2020 Bash at the Beach/The only Bash that got cancelled  )8
 

7/23/2019 7:31 PM  #15


Re: Cylinder head shopping - what numbers matter most?

Solid, now just find a nice 331 with a big roller cam and we can talk heads again

 

7/28/2019 5:41 AM  #16


Re: Cylinder head shopping - what numbers matter most?

The biggest concern for me is matching components.  You have an "RV" cam, specs unknown, but I'm going to go ahead and assume its a cam designed to bolster low end torque.  The stock hydraulic cammed 289s were basically done at 5,000RPM.  I'm thinking the cam you now have is going to be be at best in that area.

So, big compression numbers, big runners, etc. are not a good match.  I would keep compression in the 9:1-9.5:1 range.  The issue you've encountered is that with a flat top piston and the 289s tiny stroke length the swept volume in quite small, so without an really tiny chamber a 289 ends up with low compression.  You could go to a steel shim head gasket to reduce the nonswept area, which might buy you 0.25 or so in additional compression ratio depending on what the stock composition gasket's compressed thickness was.  BUT, to really get where you need I would assume you are going to need to mill the heads a bit.  It will add cost, but will also produce a more powerful and snappy engine.

A 2.02 intake valve (Chevy size) is too big, but there's not much to be done about it.  Most aftermarket head makers use 2.02/1.60 valves to keep production costs down.  Runner volume therefore becomes more important. I would not go over 170, and something in the 155-165 range would be better, but is going to be hard to find.  Though I know AFR makes a set of 165 heads.  

My advice would be to run a set of Edelbrock Performer heads.  They are the best suited aftermarket aluminum heads you will find for this engine.  They will need to be milled to get your compression right, and  would run a steel shim gasket to reduce the amount of milling needed.  Verify with the machine shop if the intake needs to be milled or not to match.  You'll also need a set of custom length pushrods most likely.  WYAI, roller rockers would also be a good idea, and I'd go to 1.7s to get a little more top end.

The TFS heads would also work, but are geared more towards a 5.0's RPM range, which topped out at 6,250 RPM, whereas the Edelbrocks are geared ore to a idle-5,500 RPM range, which is right where your engine lives.  AFRs would be better, but I don't think the additional $500 or so is justified on a build like this.

 

7/28/2019 11:08 AM  #17


Re: Cylinder head shopping - what numbers matter most?

Also  you  need to think about NOT getting a camshaft with a large amount of duration and an LSA of 112-114 or higher because........high CR +large duration + long LSA number sometimes lead to spark knock at low speeds even if..........you use hi test fuel.
All goes back to the "whole-package" when modifying an engine.
Windsor jr. iron heads like mine! have the 1.94" intake.......54cc (or58 can't remember)chambers.....cheaper than Eddy heads.....and since they are iron less worries about warping if/when overheating.... Good bang-for-the-buck.
6sally6


Get busy Liv'in or get busy Die'n....Host of the 2020 Bash at the Beach/The only Bash that got cancelled  )8
 

7/28/2019 11:42 AM  #18


Re: Cylinder head shopping - what numbers matter most?

I'm confused, mill the heads the put a shim under it?? What did I miss? Lower the compression chamber by milling it then raise it with a shim?


70, ragtop 351W/416 stroker Edel Performer heads w pro flow 4, Comp roller 35-421-8. T5
 

7/28/2019 3:06 PM  #19


Re: Cylinder head shopping - what numbers matter most?

A steel shim head gasket is about 0.020” thick. A standard head gasket is at least 0.040” thick. Cometic lists head gaskets for small block Windsor engines as thick as 0.140”.

Last edited by Hornman (7/28/2019 5:56 PM)

 

7/28/2019 4:42 PM  #20


Re: Cylinder head shopping - what numbers matter most?

lowercasesteve wrote:

I agree with the 170cc intake volume - perfect for your app, but I see a couple of issues. 

Your 289 has 54cc combustion chambers.  The TFS has 61cc chambers.  Even with flat top pistons you will reduce the compression ratio significantly; a lot more if you have dished pistons..  Meaning less power, not more power.

Those 2.02 intake valves are made for high rpm use.  You will lose flow rate at low rpm, and, one more time, lose power.

I'm thinking that a set of GT40 iron heads might do you in better stead.

I can't give you more specifics.  I will let others fill out any other  data.

If you go with a set of GT40 heads, make sure to match the valve springs with your cam. I used the stock 5.0L valve springs when I swapped over to the GT40 heads (98 Explorer) on my 351W and I ended up having to swap to heavier springs because my valves were floating at about 5K and the engine would just fall flat on it's face. The original 69 heads worked okay with the cam, but not the 5.0L ones.
 


68 coupe - 351W, 4R70W, 9" 3.25 -- 65 convertible - 289 4v, C4, 8" 3.00
 

7/29/2019 6:04 AM  #21


Re: Cylinder head shopping - what numbers matter most?

GT40 heads are a decent budget head, BUT they need to be in good shape.  They are getting harder to find, and are often high mileage at this point.  Once you have to rebuild them the costs start to rise, and there were a rash of them that ended up cracked, so at the very least they would need to be Magnaflux inspected to ensure they are sound.  If you get into springs, valves, guides, etc. you end up close to the cost of entry level aftermarket heads, but without the aftermarket heads better flowing ports. 

The smaller valve heads aren't a bad way to go, but on a 4" bore engine there shouldn't be valve shrouding issues, which is the primary reason to use a smaller intake valve.  Consider the difference between a 1.94 and a 2.02 is only 0.08"; a bit larger than 1/16".  More to the point of flow, its only 0.04" per side, as the concern with valve size is the obstruction presented by the valve head and how it impacts flow, especially at lower RPM.  I would advise that in this situation port design and flow is going to be much more important than valve size. 

Aluminum, iron, the debate continues.  There are definitely pros and cons.  Aluminum heads are considerably lighter, and in a car that already has a bad front/rear wight bias every bit taken off the front end helps handling.  Aluminum heads also tolerate about 1 point more compression without detonation compared to iron.  The other side of that being that iron heads need less compression because they keep the heat in the chamber, which promotes better atomization of fuel, more complete combustion, and more power.  Once you get into aftermarket heads you've essentially corrected for the differences between stock and aftermarket port design when comparing iron to aluminum.  Factory iron vs. aftermarket aluminum (or iron) there really isn't much comparison, especially at higher lifts.  The factory ports are compromised due to the need to reduce machining costs.  Now, they could be ported and flow can improved considerably, but the biggest problem there is that newer heads like the GT40s have a port design much more efficient than the old school heads.  They are more apt to be ruined by at home porting than helped.  To get better flow you need to farm out the porting, and now cost wise you have a head that does what you want, but also one that is still out flowed by an entry level aftermarket head that also now costs less.

 

Board footera


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