Different Heads on 289

Ping254

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Sep 30, 2007
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Hello- This is my first post here. I have a 64 1/2 mustang with a 68 289 in it. The previous owner said that he had the engine rebuilt from the bottom up by an experienced engine builder. I was taking the plugs out in preparation to replace the exhaust manifold with some new headers. In doing so, I found that the left head has small plugs and smaller plug holes than the left side of the engine. It has autolite plugs with the larger ones #45 and smaller ones #25. According to the parts store the 45's were the correct plug for that engine.

I pulled the valve covers off and the driver side head is stamped 302, the passenger side head is stamped 289. The engine starts up and appears to run real nice. Will this setup cause any problems down the road? Should I just replace one of the heads with a matching head. If so which one should I go with?

Thanks a bunch!
Jim
 
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Tim65GT

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Feb 24, 2004
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First, Welcome to StangNet. :nice:

It seems very unusual to me that your engine would end up with mismatched heads. Apparently, someone took the easy/cheap way out and replaced only what they had to.

Do you know how may miles were put on the car with this configuration?

I would do a compression check to make sure there isn't a significant difference between the left side and the right side. If you have all 140 psi on one and all 170 on the other, it would be obvious there is a difference in combustion chamber size between them and may cause problems down the road.

If they match within 10-15 of each other, you could probably go with it. You said it runs fine...

Just my $ .02 worth
 

Ping254

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Sep 30, 2007
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The compression is about 140 on the side with the 289 head and 170-175 on the 302 side. I thought compression would be lower with the 302 head?

Anyway, you said that it would cause a problem down the road with compression this different. What should I do? I don't want to spend a fortune, but I want a solid engine. Should I get a used 289 head and replace the 302, or should I just get a new set of heads from Summit or Jegs?
 

D.Hearne

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You definately need matching heads. You sure you got the readings right ? I'd pull both and inspect the 289 head, it could have the valves recessed from running unleaded gas. If you do pull them, post the casting numbers here and we can tell you exactly what heads you have. 68 289 heads had 63 cc chambers, there's a chance the 302 head has smaller chambers. Be a good time to check the stroke too to see if you actually have a 289.
 

Ping254

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Sep 30, 2007
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I think I'm going to go with some Trickflow heads anyway. I'll pull the heads this weekend and post the casting numbers.

I've never worked with a 289 before. What do you think of this setup.

Trickflow TFS-51400004 heads
Summit Rockers
Weiand Stealth Intake
Holley 4160 600CFM carb
Tri-Y headers
2.5 dual exhaust

I've never put aftermarket heads on. What else should I get when putting all of this new stuff on.

Thanks for all of your replies.

Jim
 

5.0ina66

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Jun 6, 2003
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I think I'm going to go with some Trickflow heads anyway. I'll pull the heads this weekend and post the casting numbers.

I've never worked with a 289 before. What do you think of this setup.

Trickflow TFS-51400004 heads
Summit Rockers
Weiand Stealth Intake
Holley 4160 600CFM carb
Tri-Y headers
2.5 dual exhaust

I've never put aftermarket heads on. What else should I get when putting all of this new stuff on.

Thanks for all of your replies.

Jim
Sounds like a plan, I prefer Edelbrock carbs, but that's like chocolate or vanilla. If the TFS heads don't include it, you'll need the TFS bushing inserts to reduce the head bolt size to 289/302 size. The valve configuration on the TFS heads might not clear your stock pistons, you may want to look at other heads, or rebuild the engine with compatible pistons :D
 

Ping254

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Sep 30, 2007
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The TrickFlow description for the Twisted Flows says "They don't require flycut pistons for use with cams up to the specifications listed—no other 2.020 in.-valved head for small block Ford offers these features! "

So, have you (or anyone) heard that the stock pistons wont work with these heads? The previous owner said that the pistons were just replaced on a fresh rebuild, so I would hate to change them out right now. I'm not sure if they are stock pistons or not, but I would bet they are stock. I'll find out when I pull the heads this weekend.

Thanks,
Jim
 

ga289stocker

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May 23, 2006
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I think I'm going to go with some Trickflow heads anyway. I'll pull the heads this weekend and post the casting numbers.

I've never worked with a 289 before. What do you think of this setup.

Trickflow TFS-51400004 heads
Summit Rockers
Weiand Stealth Intake
Holley 4160 600CFM carb
Tri-Y headers
2.5 dual exhaust

I've never put aftermarket heads on. What else should I get when putting all of this new stuff on.

Thanks for all of your replies.

Jim
I'm close to doing my head swap on my 289. Cast stock heads to 165 AFR's.
There's several things you may need. As mentioned the stepped washers most likely as many aftermarket heads come 1/2" holes and 289 is 7/16. Also would recommend some ARP 7/16 head bolts as well. Then you have pushrod selection, I'm going to get a pushrod length checker and make sure I have the correct lengh, don't just assume you can swap them, they may work but could be off for correct valve timing issues. Then you got gaskets(head, intake, exhaust), maybe upgrade to a double roller timing set, sealers etc...This small things add up. That's my .02...Welcome to Stangnet..
 

Ping254

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Sep 30, 2007
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I'm looking for something that will bolt up with minimal modifications. I don't want to get in a Trickflow/AFR battle, but would you recommend the AFR 165's over the Trickflows for ease of installation? I'd rather not have to get them milled or change out the stock springs. I am not going to be doing much more to the engine unless something blows up, so I don't need anything too tricked out. The previous owner said that they put a slight bigger/mild cam in when they did the rebuild, but I don't know which one or how big.

So the push rods will have to be changed as well?

Thanks!

Jim
 

D.Hearne

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The 165's would be a better match to a 289. Smaller valves and ports = more velocity and more power overall in the rpm range. You'll be happier. I'd also suggest a Holley 570 Street Avenger carb for it. You mentioned Summit rockers, I'd go with them only if they're full rollers, roller tipped only are a waste of money. And as blkfrd mentioned pay attention to the chamber cc's, you want to keep the same or smaller to keep the comp ratio or increase it slightly. It doesn't take many cc's to drop or increase the comp ratio in a 289.
 

BarnStang

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Mar 2, 2001
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When I put Trick Flow twisted wedge heads on my 93, I called Trick Flow tech support. They told me everything I would need and even gave me the part numbers. to order from Summit. You have to use hardened push rods with the guide plates. They should be able to tell you exactly what length to get, but you should always double check. Easy to do. That being said, if I had to do it over, I would also go with the AFR 165. Better choice for your application. Ditto for the carb. I like Edlebrok carbs too, so a nice Performer would be cool too! We have put a few of the Avengers on and so far they are very adjustable and tune in easy. Have only had one that gave us a fit.
Was hard to find. Max valve lift is .540 So that's a lot of cam. Stock pistons assumed.
http://www.trickflow.com/partdetail.asp?part=TFS-51400002&autoview=sku

THose are 61cc heads with single valve springs. See what others here recommed. I'm not up on what the 289 would would work bet with.
 

Ping254

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Sep 30, 2007
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Thanks for all your input. I orders some AFT 165's today. It looks like that's what most people like here. I already ordered the Holley carb, so that will have to do. I also got the Weiand Stealth intake.
 

Ping254

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Sep 30, 2007
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I got the Holley Street Avenger 570. I ordered a pushrod length checker and I'll figure out what pushrods to get later.

I decided to go with Harland full roller rockers.

How critical is a double roller timing set? Should I do that now as well, or can it wait for rainy day?
 

phazersonstun

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Feb 28, 2007
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Sound like a good setup! But I would definitely step up to the double-roller timing set. It will add to the overall durability of your engine and will give you piece of mind. Seriously, replace/ upgrade essential stuff such as the timing chain, water pump, fuel pump, get a hardened oil pump drive-shaft, and so on. Some people may say that this is a little extreme, but again piece of mind. Especially if you want to get on it and put the pedal to the metal!!!
 

68EFIvert

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Thanks for all your input. I orders some AFT 165's today. It looks like that's what most people like here. I already ordered the Holley carb, so that will have to do. I also got the Weiand Stealth intake.
Yesterday was a good day for AFR. I purchased my 165's yesterday as well. I am now planning on what pushrods I will have to use. I forgot to order a pushrod checker from Jegs when I placed the order so I'll try to score one locally. It sounds like you will have a nice combo there. You got some real good advice. :nice:
 

Ping254

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Sep 30, 2007
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You and I appear to be doing the same project:) I just ripped the old heads off today. I can still see the honing marks that were done during the last rebuild. So I guess it hasn't been used that much.

The pistons are stamped with .060. Does that mean it was bored .060 over? I get a measurement of 4.050 on the cylinders. According to my manual the original bore was 4.000 for the 289. I'm confused.

Now I'm shopping for a cam and timing set. I'm searching through old posts now, but do you guys have any suggestions for my setup? Nothing to wild.