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Discussion Starter · #1 ·
Hello - new to this forum. I just bought a 66 coupe with 289/2 barrel. I was looking to this forum for some ideas to upgrade the engine without pulling it - running well now but looking to work on it with my son and have some fun increasing power. Any input would be great I was thinking:
1. aluminum heads, they look cool and increase power, any recommendations?
2. Improved intake manifold - again any recommendations?
3. 4 barrel
4. Headers and dual exhaust - can headers go in while engine is in the car?

Thanks for any input from this group!
Jason
 

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For what it’s worth, improve the brakes first, then the suspension. If you have any money left, then work on the horsepower.

Budget BRAKE improvement:
just buy new friction material. If you have drum brakes on all 4 wheels, get the Porterfield R-4S brake shoes and have the drums turned (made perfectly round again). Don’t omit the drum machining, it costs very little and the new shoes are a waste of money without it. Then drain the old brake fluid and replace with a good DOT-4 fluid.

if you have front discs, then get the ebc redstuff pads and have the rotors tuned so they are flat .

SUSPENSION: call or email John at Opentracker. Tell him your use of the car and goals. He will advise you on what parts you need to reach your goals. Without trying to upsell you parts you don’t need. Trust him. His advice alone is worth big bucks in money saved.

the fact is, better brakes and suspension will make the car more enjoyable, not to mention more safe, than just throwing $$$ into increased horsepower. Nothing wrong with having more power, but get the priorities straight for maximum enjoyment of the car.

Z
 

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Hello - new to this forum. I just bought a 66 coupe with 289/2 barrel. I was looking to this forum for some ideas to upgrade the engine without pulling it - running well now but looking to work on it with my son and have some fun increasing power. Any input would be great I was thinking:
1. aluminum heads, they look cool and increase power, any recommendations?
2. Improved intake manifold - again any recommendations?
3. 4 barrel
4. Headers and dual exhaust - can headers go in while engine is in the car?

Thanks for any input from this group!
Jason
Aluminum heads are a nice upgrade, but you need to pay attention to combustion chamber size. You can get AFR 165's milled to 54cc. Not cheap, but one of the best flowing cylinder heads for a 289/302.

For intake go with either an Edelbrock Performer RPM or Weiand Stealth. Both are good dual plane intakes.

Carb brand choice is a matter of much debate. Stick with something 600cfm or under and vacuum secondaries. Many like the Summit carb with annular boosters.

Headers can be installed with the engine in the car. Long tube, 4 into 1, offer the best power potential, but can hang low. A good set of tri-y headers generally tuck a little tighter and give more ground clearance. Some compromise power with shorty headers solve ground clearance and clearing power steering systems.
 

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Hello - new to this forum. I just bought a 66 coupe with 289/2 barrel. I was looking to this forum for some ideas to upgrade the engine without pulling it - running well now but looking to work on it with my son and have some fun increasing power. Any input would be great I was thinking:
1. aluminum heads, they look cool and increase power, any recommendations?
2. Improved intake manifold - again any recommendations?
3. 4 barrel
4. Headers and dual exhaust - can headers go in while engine is in the car?

Thanks for any input from this group!
Jason
1. AFR #1399.
2. Weiand Stealth #8020 or Edelbrock Performer RPM #7121.
3. Summit M2006VS500.
4. Reproduction HiPo cast manifolds and 2-1/4" OE-style exhaust. Will require "HiPo" clutch equalizer bar if manual transmission.
5. Distributor re-curve by Dan Nolan at "The Mustang Barn".
6. Recommend replacing cam and lifters using Holman-Moody C9OZ-6250-C cam.

Should run like a scalded rat.
 

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The above mentioned AFR heads are good, but I wouldn't bother with them unless you plan on a ground up rebuild with all parts matching the intended performance level. I would concentrate on brakes, suspension and for the engine limit the upgrades to a four barrel intake and dual exhaust. Then tune the carb and the ignition as good as you can and off you go :)
 

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Discussion Starter · #6 ·
Thank you all for the replies! The engine upgrades are great recommendations and exactly what I was looking for.

I am also doing the suspension, it’s in good shape but all stock. I was planning on using the street or track stage 5 but thanks for the info on open track, I will call them to see if they have a better product.
 

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I wouldnt go crazy on suspension mods. Update to the Shelby drop, its proven. Or better yet upper A arms that will allow you to get +3 degrees of castor along with the drop. And adustable strut rods. CJponyparts has a sale on specialty products upper adjustable A arms with adjustable strut rods. 50% off this weekend. They combine a Shelby drop cross shaft, and the castor adjustments you want. No drilling of new holes required. When these cars were built they used bias ply tires. Radials require different alignment specs. That goes for all older muscle cars too. Make sure your rear leaf springs and hardware are in good shape as well. For your engine, skys the limit. But I will caution you. Be careful of what you build. I have a classic car with over 500 rear wheel hp. Yes its got power to spare, but quite honestly, my 289 A code built to factory specs is a nice driving car. I would like another 100 hp out of the engine though. AFR 1399 heads, a hydraulic comp cams camshaft, an Edelbrock dual plane intake (30 hp alone) and free flowing exhuast will get you that. Have fun!
 

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Discussion Starter · #10 ·
Thanks for these inputs, especially the street or track suspension info.

one more question with heads, I have stock 289 pistons in this 66 coupe, it sounds like there are clearance concerns with flat top pistons when upgrading to bigger aftermarket heads, is this an issue?
 

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Thanks for these inputs, especially the street or track suspension info.

one more question with heads, I have stock 289 pistons in this 66 coupe, it sounds like there are clearance concerns with flat top pistons when upgrading to bigger aftermarket heads, is this an issue?
There are issues with intake valve diameter in a stock 20* head. There's really no reason to exceed 1.9" in intake and 1.6" in exhaust valve diameter. The second potential issue with piston-to-valve clearance is in the selection of the camshaft and how far the valves are open at TDC on the exhaust/intake stroke.
 

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Thanks for these inputs, especially the street or track suspension info.

one more question with heads, I have stock 289 pistons in this 66 coupe, it sounds like there are clearance concerns with flat top pistons when upgrading to bigger aftermarket heads, is this an issue?
This and many more details are the reason I say that (things like) AFR heads are great, but on an engine that's build up from the ground. That doesn't mean that everything has to be of high end race spec, but everything has be in good condition and matched to other parts. Otherwise it will be mismatched disaster. If you want to go that route, by all means go for it. It's certainly doable and fun.

If you have other things on your mind/list/budget for now, I would keep it simple and stick to a few simple upgrades like an intake manifold and a well tuned carb.
 

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I'll write a separate thread about the installation and a simple review of the new suspension parts I just recieved from CJ that I mentioned in my earlier post. But just looking at the pieces out of the box, they look very well made. I have a complete coil over suspension from a high end $$$$ manufacturer under one of my other cars, quality of welds, materials used appear to be equal. I had installed new GT front coil springs when I put the Mustang together initially 2 yrs ago, along with KYB gas shocks. So, for about 11-$1200, that is about as budget friendly as you can get. I guess the next upgrade would be a bit better shock. But this is a street driven car, not a track car.
 

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My take on things is that cylinder heads are not super chargers and not turbos. They’re only going to improve performance if your current heads are a restriction to your power goals. Being automatic especially you need to be more particular in matching everything. The 289 is a great little engine but it’s big problem is being a short stroke and large bore means your combustion chambers are going to be on the large size and volume. Keeping that ratio in size to the volume of the cylinder is going to be more challenging. When Ford advertised the compression ratios of theses engines are more “advertised”. Very simple calculations excluding a lot of important factors such as valve reliefs, head gasket volumes and exactly how far down the bore the piston is at TDC. These are mass produced and not blue printed engines. So it comes down to instead of a A code 289 having 10:1 it’s closer to low 9’s. A C code is what 9.2 or 9.4? It’s probably much closer to low 8’s. Now a lot of aftermarket aluminum heads are more geared to a 9:1 compression on a larger 302/5.0 engine and as such have around a 65cc combustion chamber. As I said a C code is probably closer to low 8’s and that’s with a smaller 55cc chamber or so Ford says. That extra 10cc of volume is a easy full point loss in compression.

Now aftermarket heads are going to breath much better and are going to fill the chambers much better which will offset a lot of that compression loss. Except at lower rpm where the engine will feel lazier. I would lean towards having a shop go through your current heads. Put the larger 351W intake and exhaust, they’re 1.84” for intake and 1.54” on exhaust. A mostest increase but then again you’re doing modest work. Your shop will do a multi angle valve job, clean up the valve bowls, nothing crazy and slightly open the exhaust. It’s not crazy work and not going to be crazy expensive and should give a very nice bump in performance. For a cam, nothing crazy. Something like a RV type. But don’t ask me for a specific cam, who knows I could recommend a Cummins diesel cam. Call a cam company. They will ask a lot of questions and give you free expert advice.

For intake, again nothing crazy. For your use and build a Edelbrock Performer 289 will or should be fine. They are designed to work on street cars in rpm range where we drive most of the time. You should be able to find a good used one reasonably, about $125. For exhaust shorty headers will be fine. A stock 2” dual system with a turbo type muffler will be fine. A few years ago I put a junkyard Explorer GT40P into my 66. Initially I was going to run stock exhaust manifolds so I could do a 1 day turn around on swapping motors and put headers in during the winter. I was really eager to see how my exhaust manifolds would work. I hade matched the manifolds to the exhaust ports which are much larger then the 289. I also noticed the outlet of the manifolds severely reduced in size just before the exit. I would say maybe 1.5”! I ground them open to the full size. Unfortunately never got to use them as the Z bar adapter for the clutch linkage prevented that.

I would highly recommend sending the distributor out to a shop that does recurring. This is a great low hanging fruit modification. Probably one of the best things you can do. It really can make or break your engine performance. I can’t say this enough!

You don’t need to go crazy on mods just have everything working together. As I mentioned I have a Explorer 5.0. Nothing crazy, only thing I did was swap the cam for a stock Mustang 5.0 cam that is slightly hotter. It’s all cheap used stuff. I have maybe $1k into the motor and that includes the motor, new billet flywheel, new balancer. I’m having issues uploading a clip to YouTube or I’d show you how well a somewhat sorted out combination of parts will work. I’d suggest thinking of swapping in one of these motors but you said you want to leave the motor in which is ok.

As far as suspension. I don’t race but I did do a lot of work on my suspension. All aftermarket tubular control arm. I spent a lot of time understanding what I needed to do. I’m happy with my results but what’s right for me is not for someone else. I’m not trying to talk you into what I did but more to say I went down the same road as you are now figuratively speaking so I can give you some hind sight thoughts. First you absolutely do not need to do what I did to have a great handling car. The absolute most important thing is to have everything in good shape, no worn out stuff. The single best thing you can do is lower the upper control arms period. I like the roller bearing idler arms. Bart raised concern about roller bearings for a static load. He’s pretty much right. You typically do not use roller bearings for static loads for his stated reasons. I avoid using them for a while for these reasons. I’ve been to a roller bearing seminar too. It wasn’t until I saw roller bearings listed for static loads did I give it a shot. 10 years later, no issues. Besides if nothing else they’re going to far out last stock rubber bushing perches and who wants to change them on a regular basis? If the money is there, adjustable struts. You can fine tune caster but the money shot is that they act consistently where as the stock set up with rubber bushings that compress erratically don’t. They’ll improve day to day driving but they’ll really shine under harder braking. The car will no longer dart around but will simply stop dead straight. Nuff said. Shocks, you get what you pay for. Good handling does not mean stiff ride IMO. If you can I highly recommend investing in good shocks. Either Koni or Bilsteins. It’s money well spent. Last, good alignment. I would say 1/2* negative camber with as much caster as you can get. You want at least 2* positive caster, 3 would be great. With the stock suspension with shims you’re going to be limited and it’s going to come down to a dance between caster and camber. Do anything you can to stiffen the front end up. Such as a Monte Carlo bar between the shock towers and a export brace between the towers and fire wall. Install a 1” front sway bar. You don’t want or need one on the rear axle with the leaf springs.

You don’t need to spend crazy money just buy a few right parts. Don’t be in a rush to do this or that because you’ll probably end up redoing it later arm. The more you can learn, the better off you are. Have fun driving it in the mean time. This photo was from a opening day at Watkins Glenn. 3 paced laps at 55 mph for $25. They’re typically fun and a couple times they got a little lax with speed and I saw 115 mph a few times on long straight sections.
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