289 Engine Rebuild - Heads & Bracket Question

[Wild]

I have a 1698 Bronco with a 289 - I have a couple of questions:

First the Factory 289 Heads are not able to be rebuilt so I am wondering what I have for options. Not necessarily looking for horsepower or anything that has any bling to it, as the truck is still stock and sporting its original paint (3 On The Tree - 3.03 Trans)

Pricing out new heads I found that there are cheaper aluminum options over the cast ones offered, but is there a newer head that would be a plug and play off a 5.0L that I could get rebuilt. I am still running the 2 barrel carburetor, stock manifolds, I am thinking of upgrading the cam shaft when I put it back together. I am looking to keep the stock appearance but want something reliable.

The Block is a 302 C8AE-6015 with 289 Heads

My second question is the bracket that holds the alternator seems to have room for another bolt on item. What was bolted to this bracket?

Thank You

 

[suthernboy]

What's wrong with your original heads that they can't be serviced (rebuilt)?

 

[suthernboy]

Was this a California truck? Could the extra mounting location on the alt bracket maybe be for an early emission air pump?

 

[broncnaz]

Welcome, Dang you have one old bronco. lol

Some engines had smog pumps or A/C. so thats what the extra hole is for in the bracket. Your probably had a smog/air pump
Pretty much any head off any 302/5.0 will work on your engine. If your rebuilding it then you you'll want to pick pistons that will give you the compression ratio you want with the heads you choose. So in that case just about any head you want to use will be fine. Just be aware that heads from 77 up have different rocker arms so you'll need them as well. But Id advise against going with heads from 77 to about 85 as they will have big combustion chambers and your lose a lot of compression. later heads will still lose compression but not as much.

If you are just replacing the heads then you'll probably want to find heads with small combustion chambers ie 58cc which is what your 289 heads should be otherwise you'll lose some power especailly if you go with a bigger cam it just wont make the power it could. Whats wrong with your 289 heads that they cant be rebuilt?

As for what heads will be your best bet. Well GT40 and GT40p heads top the list in the factory department mostly found on explorers. Next would be the very common E7 head used on pretty much everything from 1987 on up.
GT40 P heads would show the largerst gain but they have a issue of spark plug angle although if I remember correct they will fit with factory manifolds.
You may be able to pick some up for dirt cheap from other people that are upgrading to better heads. but keep in mind that you may need to rebuild those as well and that can drive the price up even more so the cheaper you can score them the better. Otherwise you may be better off with aftermarket heads. I know when I was rebuilding my engine I was going to have my stock heads rebuild and setup for adjustable rocker arms it was going to cost just a little less than aftermarket heads that were hands down better than any stock head no matter how much money you dumped into them. So Just weigh your options. Sometimes you can even pick up cheap aftermarket heads from the mustang crowd as they upgrade.

 

[904Bronco]

I have a 1698 Bronco with a 289 - I have a couple of questions:

smog pump...

 

[Wild]

The truck spent its life in Montana - It was primarily used as a plow truck at the owners place in the mountains it has only 68,000 miles but I am assuming they were hard miles being used as a plow truck. One of the valves was trying to make it way through the head and I guess the machine shop thinks that he may have to go too far into the head in order to fix it.

 

[Wild]

I appreciate your help, this is my first Bronco so I am fairly new this whole game.

 

[suthernboy]

Too bad about your heads, I always gravitate toward older iron when possible. They are so clean, too. What a shame.

I think I am doing about the same thing with my '76 as you are talking about doing with your '68; a little more power with modern components but keeping it as original in appearance as possible.

When I tore mine down I found the PO had replaced the original D5 heads with the very common and very inexpensive E7 (later mustang GT) head. I was dismayed as mine is otherwise numbers matching, so I started looking into getting some original vintage heads. I found that most folks consider the E7 heads "boat anchors" (compared to the more scarce and expensive GT40 variations), but it seems the D5 heads are even worse. So I started thinking, wait a minute, the E7 heads were on Mustang GT's which made decent power.....I'm not building a bracket racer, so they should be fine on my Bronco. Since they look virtually identical to the D5's from the exterior, I decided to use them.

I did make some modifications. With a conical burr in my die grinder, I cut the emission "humps" out of the roof of the exhaust ports (about 15 minutes per port), I port-matched both the I & E ports to the gasket and the intake manifold ports as well (another 15 minutes per port), and I had the machine shop mill the heads .030 to reduce the combustion chamber volume (you can go .030 without having to mill the manifold and the stock intake bolts still line up properly). Now, .030 doesn't give a lot more compression, but it helps SOME, and you know you've got a nice flat head, and it only cost me $50. Of course, they got a complete service and multi-angle valve job.

If you go with later heads, you'll need different rockers as Broncnaz said above. I found a set of factory Ford/Crane rollers off of an early 90's Mustang Cobra for $75. They might have come on other models too, not sure. They attach with an Allen bolt -vs- a stud. They're non-adjustable, but I never liked adjusting valves anyway (that's why they invented hydraulic lifters). Pair roller rockers with a nice roller timing chain and you get a few extra "invisible" horsepower.

With the new rockers you'll likely need new pushrods. Order an adjustable "measuring" pushrod and find out the exact length you need before buying them. It's easy.

Good luck.

 

[No1hedberg]

Late model small block heads are ok. You get the benefit of hardened exhausted valve seats, which are a must on modern unleaded fuel. Of course you have already discovered the math of properly machining old heads vs. aftermarket aluminum heads. If you search Craigslist you will probably find a cheap set of GT 40/P heads which are excellent cast iron options. If you decide at go aluminum, beware the ultra cheap heads out including Edelbrock E Street versions they are Chineese and very poor quality.

 

[broncnaz]

Yeah those heads appear to be trash it would cost quite a bit to fix them on top of that they are big chambered heads 63cc so you'd be better off with late modle heads all around.