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It's safe to say that ANY aftermarket aluminum head ( China or otherwise) is superior ( air flow wise) to a production iron head including '69-70 351W or late model GT40 and GT40P heads. Porting those iron helps "IF" the person doing the work knows what they are doing. It's not as simple as just grinding away and making the port bigger. Using the repop HP iron manifolds takes away "most" of the increase in performance because they become the "restriction" (compared to tube headers). It's also important to remember compression with an aluminum head can be higher than with a cast iron head because the aluminum head absorbs more heat ( energy ) than an iron head.
For "street performance" it's more about making all of the improvements work "together" , not "excessive".
Randy
 

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I'm probably in the minority in that when I was faced with this decision, I decided to stick with my iron heads and have them worked on. I paid $650 for a full rebuild and intake/exhaust porting (also included porting of my intake and exhaust manifolds). I am very happy with the work that was done. When I started doing the research, it seemed the absolute cheapest I would get a set of heads I could trust would be about $1000. While I saved money, the bigger factor for me was that I wanted to retain as much of the original flavor as I can. That doesn't mean they need to perform as they did from the factory, but I think it's cool that I'm running vintage stuff in my vintage car. Obviously if/when my block gives out I'd upgrade the heads at that time, but for now, I decided I wanted my 289 to wear the same heads that it came from the factory with for as long as it could.
 

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I went with the AFR165's and they worked great on my 289. I went with the smaller 58 cc combustion chambers. A quick check showed the larger valves would hit the stock pistons, which did not have valve reliefs. KB116 pistons worked great to get me gobs of clearance AND put the CR back to about 10:1.

Point is...as others have said you need to make all decisions before you start buying parts. You need to keep your compression ratio up or you will kill your power. AND...you have to have valve relief with big valves and even a moderate performance cam.

Phil
 

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I am rebuilding the original 289 engine in my 66 Mustang Coupe. I am rebuilding as a Hi Po, 4V holly carb, dual plane intake manifold, Hi-Po exhaust manifolds, 2.25 exhaust pipes with turbo mufflers with resonators, mild Competition Cam. Which would be better/ cheaper? Have machine shop rebuild original heads with parts in cam kit or aluminun ready to install heads on ebay for $600.

Thanks, Steven
One key ingredient missing from this post is what you intend to do with your "new" engine. As indicated in another post in this thread, if your focus is maximum horsepower or maximum torque, be clear about where on the power band the power is being made (ie: above 5500 rpm may make for a slug off the line and the need to rev the crap out of the engine to feel the gain in power). Think about how you expect to be driving your car and what performance goals you have for the type(s) of driving you will be doing.

As for the parts themselves, the good news is that you have lots of choices. The bad news is that mixing and matching "go fast" components from different manufactures is that choices must be carefully made and, to the maximum extent possible, all parts work well with all other parts to achieve your performance goal. Define your goals (drag, track, daily driver, cruiser, or ?) search out and go talk to others that have already made their build choices to see how satisfied they are with those choices. For example if you plan to open track your car attend open track events and talk to the winners to see if they might share their ideas with you.

In the end, keep in mind that old racer's maxim "Speed costs money, how fast do you want to go?"
 

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Here is an example (now remember this is Desktop Dyno, not an actual dyno). 308CI, 9.67:1 comp, E-street heads with the smaller valves, Comp Cam 256H, alum performer intake, 500 CFM carb for he simulation (I have Sniper EFI), HiPo Manifolds and a stock style "GT" dual exhaust.
738628


In my playing with Destop Dyno I was able to closely replicate stock Mustang engine configurations, giving me confidence that this is at least a good comparison tool. Do I think my car will make these numbers? Maybe, but the point is I wanted low end grunt and don't care about going over 5500 RPM. So the E-street heads were a good choice for my motor build.

Below is a "stock" A-Code 289 I modeled a while back just for reference.
738631
 

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You can polish a turd but it is still a turd! I know because I did it. The BEST ported cast iron heads may have peak flow of 215-220 cfm on the intakes which a crappy piece of crap Chinese head will achieve with much less effort, about 50 lbs off the front end, and less cancer from porting the aforesaid cast iron doorstops. Don't even mention the exhaust ports which are about as constipated as Wilbur on free cheese night!
 

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Staple, consider keeping the original iron heads. The guys who are calling them crappy don't understand what they are talking about. YES, aftermarket aluminum heads can flow more. But if you bolt on fancy new aluminum heads, and then choke it down with your twin 2 & 1/4 exhaust....you'll gain,.....nothing. You may even lose abit because almost all of the aftermarket heads have combustion chambers bigger than the 54 cc that a 289 needs. What is more importnt, the 'better' or the 'cheaper' ? The factory irons can support 400 ~450 if they are prepped right. Is that enough ? LSG
 

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If it came down to the two options of spending $650 on porting your cast iron heads or putting that money towards new aluminum heads I'd definitely go with the later. Aluminum is going to be much lighter, better performing and isn't going to run as hot as the aluminum heads will dissipate the heat much better than cast iron. You should be able to find several reputable brands of aluminum heads for around $1000 for the pair. Trick Flow, Edelbrock, RHS and Dart come to mind.
 

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I had my C4OE heads rebuilt, valve work included hardened valve seats, 1,94" intake, 1,6" exhaust valves, threaded rocker studs, ported intake and exhaust, milled mating surface, The cost was $650 back in 2010, I thought about a set of used aluminum heads for about the same price but wanted the smaller CCs that were in my stock heads.
 

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$850 seems a little high to just rebuild your stock heads? As I recall, I had mine done for under $400, and that included resurfacing, new SS valves, 3 angle valve job, and guides. Also assembly including setting the springs to proper LB at lift.
That machine shop is known for quality work, so I could rest assured that what I get back from them will be right.
There is one other person I am going to check with to see what he wants to do the heads.
Machine shops aren't as plentiful as they once were.:(
 

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I would like to see a "streetable " , 400 hp 289 with factory 289 heads , I don't care WHO ported them , headers or not. We do "vintage road race legal" ( not streetable) engines with 351W or original '66 GT40 heads and 12+ compression that are around 450 and it's allot of work.
I agree with you that a 250 CFM aluminum head hooked up to stock cast iron exhaust manifolds is a VERY bad idea ( performance wise) but so is a ported 289 head with a stock cast iron exhaust manifold. Many guys build engine combinations where the components "fight " each other. Too little understanding and too much reliance on "buzz words". Just this old guys opinion.
Randy
 
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