Hi guys,

I have an old Ford Bronco which used to have small chamber 289 heads, but those have crapped out so I need new ones. I bought some Ford E7TE heads which started on mustangs in 1987. They are a decent iron head, I got my pair for $90. They came off of a running '94 F-150 (these heads originated in the truck line before being appropriated by the car line), and came with rockers, valves and springs. This truck is my driver when the roads are snowy or icy, I use it 4-wheelin', etc. I can't remember the cam specs off the top of my head, but this is a low RPM torque cam. For the past 7 years I have been running the stock 2-barrel carb on the original 1969 cast iron intake. I now have a performer intake and carb although I am probably going to go with a Quadra Jet soon for better off road performance.

The thrust of this post is how much porting is too much on a set of heads for this vehicle and use. If I do this to my heads will I lose the port velocity that is so important for torque? I have so far worked just a little on the exhaust ports grinding down the Thermactor bumps, and squaring up the ports. You can see that this guy ports and flows, over and over. If I were to grind down the guide bosses, flatten the pushrod tubes where they intrude on the intake port, remove the taper of the bowls, slightly unshroud the intake valve, and polish the ports and combustion chamber will I kill the low end torque of these heads? Many of these sites re: porting these heads are of course, put up by racers looking for high RPM horsepower.

I suppose I have been long winded enough and you all get what I am trying to do and what I am trying to avoid. Any tips or hints would be really appreciated.

Thanks guys, Bob



[Modified by BobMachus, 7:33 PM 11/21/2003]

 

If you look at his final intake port mold compared to the GT40 head, you will see that he botched the bowl port by removing too much metal. He didn't need to remove any metal from the big bottom cuts on the intake (or exhaust) to get best performance out the head. The bottom cut should extend untouched for about 0.25" toward the short side radius, then it should be radiused into the casting by removing a minimum amount of metal. This will put the port cross-section at about 80% of the valve diameter, giving a port area of about 1.5sq. in. That is perfect for those truck heads and the 1.79" intake valve.

I "ported" my E7TE's for my 1986 351W, and it really woke up the upper RPM and the midrange with no low-speed loss. The only major cuts were at the thermactor. Here is a summary of what I did:

Exhaust
Removed thermactor and blended surface straight
Blended bottom cut into port all the way around
Cleaned up port (minimally) without making waves

Intake
Blended bottom cut into port all the way around
Narrowed valve guide boss, but kept leeward side metal
Cleaned up port (minimally) without making waves

Chamber
Blended top cuts into port where needed
Minor unshrouding
Polished chambers, then bead blasted

Valves
Valve job including a back cut on the intake valve

Guides
Guides were within tolerance, but went ahead and had bronze guides installed which were then reamed out of tolerance. :mad Stinky and uses oil.

My heads give me about 300HP at 4200RPM in my 351W with 8.8:1 compression and headers. I put a shorter set of 1 1/2" headers into 2 1/2" collectors on the engine and was surprised that the engine would rev straight through 5000RPM. I use a longer set of headers which covers my prime operating range of 2400-3100RPM. I am using the Performer cam which is a lazy 204/214 with LSA=112 and ILCA=107. I could have done better for my operating range with one of the RV cams, like a snappy 205/210 with LSA=109 ILCA=105. Simulation shows the same power for both, but better low-end with the RV cam.

I hope this helps you. Just don't try to change the shape of the ports. They perform very well in their intended operating range with just the minor blending of the bottom cuts. Also, the Performer 302 EGR is the modern and better performing manifold versus the Performer 289.