I used to hang out at www.corral.net about 8 years ago when things were a little more sane there. There was a guy whose name I can't remember who used to build the 5.0 HO and retune it for a living. His experience and advice was to stick with the stock HO cam. You can get plenty of power by tuning the other parts. Pesonally, I think the E303 cam would be ok, but the stock cam would be better for fuel injection, and especially with the E6 heads.

The E6 heads gets trashed-talk on the corral board. Most over there think the E7 head is better. I disagree completely. The E7 head is a pretty 'open chamber' design. The E6 is a closed chamber design that should give more torque and power at lower RPMs. But you have to zero-deck the pistons.

I wouldn't 'unshroud' the intake valves. Shrouding the valves actually has a benefits; it causes all the fuel that's drawn into the cylinder to be concentrated in the center of the chamber. Fuel drawn into the side of the cylinder will cause a rich zone and cause a corresponding lean zone on the other side of the engine. Ford actually got a patent for the technique of shrouding the valve to improve the air/fuel distribution. The technique was used extensively on 60's windsor (221/260/289) engines.

Grinding the smog port bump doesn't yield any airflow gain at low RPMs. From what I understand, the bump might actually reduce reversion. The majority of airflow follows the port floor so that's where you'd want to focus attention. If you can increase the rate of flow on the short side, that will improve the reversion characteristics. The first thing to do is to smooth any edges left by the valve job. Way more power is made with attention to a good valve job than can be made by porting.

Most 5.0 headers are 1 5/8", but you might want to go with the 1 1/2". The unequal length headers will work fine.

For the money, I think the best investment would be a 3.25" stroker crank. I'd go with stock rods if you could find flat-top pistons with the right compression height. But it sounds like you've already got pistons, so save the money for the SEFI conversion. Otherwise, a highly tuned but stock 5.0 has a ton of torque.

BTW, I bought three SEFI manifold/TB/EGR/injector setups, usually on the Corral's parts for sale forum. The price used to be pretty cheap for the stock stuff, like $75.

Good luck. I'll be doing a similar build this winter for a 53 Studebaker pickup; SEFI with stock roller cam 5.0 with E6 heads. The engine's coming out of an 85 Lincoln. Zero deck block, flat-top no notch pistons, pocket ported heads. Tune the computer and install it with an AOD. If the crank needs work, I'll go with a cheap stroker.

 

Yeah.. that's entirely possible.. but what about at higher rpms? If memory serves me, the '86 motors were the torquiest of the 5.0's, but they ran out of steam before the E7 equipped 5.0's. The exhaust port hump is hugh compared to other ford heads, it blocks probably half the port area.. so it's definitely a restriction once the rpms come up.

I don't agree with this comment. That will apply to the intake port where air is being drawn in, but not the exhaust port where expanding gasses are forced against the roof of the port, even at lower rpms.

 

I agree with Conanski's disagreement.

The rule for amatuer porting of SBF's has been: "Don't touch the short radius turn." Although the port volume will be increased, it may kill the flow velocity at all rpm. Removing material from bowls and a little from the roofs, along with getting rid of the bumps in the exaust side, seems to work best. The Cleveland guys even talk about adding material to the floors, because they are so big to start with.

 

PCMENTEN; If you'd look at a cross section of the Exhaust port, you'd blow your "flow follows the port floor" theory completely out of the water.The majority of the flow will be concentrated up, not down, removing the thermactor bump does yeild improved flow, Ford will be the first one to tell you that. They suggest removing the bumps in their 5.0 book. Only reason they didn't do it at the factory was the increased cost. Ditto for your thinking that the shrouded intake valve moves the air/fuel mixture closer to the center. Not going to happen. Ford shrouded the valve to make the incoming flow, swirl around the cylinder, to improve the mixing. All this is compressed back into the chamber when the piston comes back up, so it's all in one place. They also moved the spark plug closer to the center of the chamber to improve ignition, this was carried over to the GT40P heads(they both use the same, longer plugs)

 

I can verify that even with the intake valves unshrowded some, there is still a ton of swirl action happening with these heads, and it does a very good job of promoting complete combustion. On my motor there is a distinct tan/brown combustion wash that's heavier on 1 side of the spark plugs, and I run 18deg initial advance on 87 octane fuel with no sign of detonation. I agree that these heads are not nearly as bad as some would have you believe.. there is lots of potential in them, it just takes a bit more work than with E7s.

 

Below the speed at which the air separates from the port walls, it will take the shortest path between high pressure (the cylinder) and low pressure (the tailpipe) - the port floor. Also, if the speed of the exhaust gasses at the port floor is very different than the speed of the gasses at the roof, there will be a path for reversion. By improving the speed of the exhaust gas at the port floor, you decrease the difference between the roof and floor and cause the center of the flow speed to occupy the center of the port instead of hugging the port roof. The thermactor bump adds a restriction to the port roof.

Check out David Vizard's research about this. He does a good job of explaining why a well shaped port with the smallest diameter is better than a oversized, polished port.

With regards to shrouding; from what I've seen in the more recent publicatons, the intake valve is more than big enough to maximize torque. Once you have a big enough inlet valve, the focus becomes on optimizing the mixture. They've published pictures showing the soot patterns on pistons tops that demonstrate the concept of fuel distribution within the cylinder. They've simultaneously shown the graphs of torque production. Shrouding helps direct the fuel into the center of the piston, preventing lean and rich spots.

And I still think the E7 heads are losers. Don't replace E6 heads with E7 heads no matter what you hear. Try to find some F7 heads. They're a lot like the E6 but with larger intake valves and better exhaust ports.

And thanks to everybody in this discussion. This is great.

 

I don't personally have any experience with the E6 heads, but my brother is very happy with the motor I built for his F150 using the total package deal (TFS cam) from www.thumperoforangepark.com. Not a bad deal compared to the price of aftermarket heads and/or pro port work.


Pete

 

You just deep sixed your own theory here about the E6's. The F7 is more commonly refered to as the GT40P head, which has the chamber of the E7 head, the spark plug location of the E6, and as you said, bigger intake valves and a larger exhaust port.

 

Simply doing a couple hours work with a die grinder on a set of E7's will produce a head almost equal to the GT40P head, only less the spark plug location and larger intake valve.

 

Iv'e always liked the E6 head for tourqe applications. I think it'a good head, were real high flow isn't really needed. I have a pair, but I eventually stepped up to the TFS Twisted Wedge and/or aluminum GT40 Swirl type heads, as a matter of policy in my builds. One of the brothers (IRRC Bryan) at BBK used to use a mildly ported set of E6S's for a SCCA road racing 86 Saleen Mustang. As I recall, he had laid the chamber wall back a little bit on the quench side, using a slight angle from the intake valve seat and this really helped. It wasn't so much, as to destroy the swirl effect. The ports themselves are essentially the same as E7's. You can get the E6's to support good HP, if you do enough careful work.

Ford patented the swirl combustion chamber eventually used on E6S heads in 1968. In terms of combustion swirl, they work great, but you just can't completely get around the shroudings ill effects. It was a great idea, but it needed further development. This is basically the reason why such things as Twisted Wedges and Turbo Swirls exist. With those heads you get the swirl combustion chamber effects, but the valves arn't shrouded.

 

Hi baddad,

I think the E7 heads are much more open chambered than the E6 and the F7 heads. I have a pair of the F7/GT40p heads in my garage. They have a lot of quench.

I think the reason that the E7 head makes more top-end power than the E6 is because the open chamber unshrouds the intake valve and allows more flow at high RPMs.

I haven't had the E6 heads off of either of my 5.0's yet, but I'm pretty sure that the combustion chamber is more like the F7/GT40p than the E7.

Either way, I think the E6 head, with its large quench area, is a better low-rpm torque producer than the E7 head. I might steal the E6's off of my Lincoln's 5.0 to use on a 351w block I have sitting around.