[rdwright66]

Anyone have a suggestion on the best aluminum head for my 66 289. I currently have a 289 performer intake, 4160 Holly 4bbl, K code exhaust manifolds, Mallory Unilite distributor, no ac or power steering, T-5 conversion with hydraulic clutch.

If anyone could tell me what heads they have installed and if they like them, I would really appreciate it. I'm considering AFR 165's non emmission legal with stud mount rockers so I can reuse my 1.6 magnum rockers currently installed. I also need to make sure exhaust manifolds will bolt up to new heads.

I'm hoping for a decent increase in Hp and lighter front end.

Thanks,

Rich

[EagleAutosports]

The AFR 165's would be ideal for it. Not too large but they flow some serious air. Well worth the money and any larger than the 165cc ports would be overkill on a 289.

[5.0 in a 66]

AFRs are pretty much IT, if you ask me. The non-emissions 58cc AFR165s would do nicely here. The exhaust port location is the same so it will all bolt up.

On second thought, did you say exhaust MANIFOLDS? That's like having a 1hp shop vac breathing through a Mickey D's straw and then hooking a 5hp vaccum cleaner to the same hose and expecting a giant increase in performance.

Get some coated headers

[rdwright66]

I want to go with the Tri Y headers, but concerned about clearance with the shock towers. Does anyone know which headers will work on 66 coupe without AC or power steering. 5 speed car with hydraulic clutch. Would appreciate any advice, I really don't want to cut in to shock towers to make room, but it is a pretty tight area.

[argo]

I have tri-y's on my car .. 289 66 coupe C4 no-ac manual steering. They fit pretty good, and have enough room to pull on off when needed. From what i have read the problems with exhaust start to show up when you have 351w's and such. You should need no mods to the shock towers for 289's 302's...

[5.0 in a 66]

Originally Posted by rdwright66

I want to go with the Tri Y headers, but concerned about clearance with the shock towers....I really don't want to cut in to shock towers to make room, but it is a pretty tight area.

OMG! Not making fun of you or anything, but I've NEVER seen headers that required shocktower mods on mustangs. It'd be interesting to see though, I dunno whether I'd laugh or cry. Your primary concerns would be mechanical clutch linkage and PS but you have neither to get in the way so you're good to go.

[not2brite]

I know it becomes an endless chain but you need more than a head change to make power. I would think about heads, cam and headers for the following reasons:

Changing to AFR 165s will provide the capacity for better breathing. However, I would not change the heads without helping the exhaust as the change to aftermarket heads will lower your compression ratio. If you just change the heads you might be very disappointed in the power category. Your 289 now has 52.6 to 55.6 cc heads and the smallest cc AFR head is 58cc.

You didn't mention cam specs but, if you are running a stock cam, you will have an excellent opportunity to upgrade while you've got the engine down to the shortblock for the head change. A flat tappet cam, 16 lifters and 16 pushrods is a cheap way to ensure you get the most out of all your intake, exhaust and head money.

Any of the reputable cam companies will help you pick the right cam.

[Mark64.5]

I agree with with the previous post, if you put a set of free breathing heads with larger combustion chambers on your 289 you will kill your low end power without making other mods. My friend took a set of small cc heads; had Chevy valves installed and we did a little porting to open up the valve pockets. He's running a performer cam and the Edelbrock dual quad setup. This combo kicks butt! He can a run 12.75 1/4 with a 4 speed and 3:89 gear in his 65 FB.