I was poking around on an Australian truck web site. They had lots of six cylinder engines, (I'm sure there was a 300 in there somewhere) Anyways, several had a crossflow head, something I haven't seen before on any ford 300s here in the U.S. Is it a fairly common mod? What are the benefits and disadvantages? Is it just something different to do? Thanks

 

I'm not sure if I've been specific enough. The header was set up so that the intake came in from the driver's side of the truck and the exhaust just stayed in its normal location. I'm not sure of where or even if the spark plugs were moved. Anybody have any ideas?

 

Fantastic mod. You'll probably need the Aussie manifolds, but it's totally worth it. Grab it if you can.

They do high performance over there in OZ. You can get practically any GM car (Holden) with an LS1, and they were making SCREAMING 300 and slant-six motors back in the day. A crossflow head turns a 300 into a wicked motor. Just look up the Frenchtown Flyer.

 

Not sure that FTF is using a cross-flow 300. As far as I know, the cross-flow six heads are almost all for the small block and not the big block. The only exception that I've come across was a proto-type series that reputadly doesn't flow any better than the stock head.

 

FTF I think uses welded 351W heads. You're right about the crossflow; I think. It was on the 250 small six. Someone out there is making an all aluminum crossflow race-only head.

 

So if I had wild imagination and free access to a good engineers shop, could I build a cross flow header (purely hypothetical) out of one and a half windsor heads?

 

The problem with that is that the coolant journals don't line up. It would only be good for drag racing.

The benefit of a cross flow is seperation of the intake from exaust thus removing a major heat source from the intake runners. (cooler air has a higher density).

 

So it's strictly for drag racing? Is there anything else that would match up or am I just spitting in the wind?

 

For a cross flow? Basicly spittin in the wind.

There an old thread over on Classic Inlines forum about a couple of the suspected proto-types being available. As far as I know they're still available but expensive.

I presume that your looking for better head flow. In that your in a little better luck than I am. Since your 77 is carb not EFI there is more "room" to port-n-polish as well as larger valves. Then it's a matter of which cam you select and the rockers you use with it, but you will get better air flow. There are also intakes available from Edelbrock and Clifford that flow better than stock. Headers or polished EFI exhaust manafolds will improve outflow over the log manifold.

Long term, Classic Inlines is developing an aluminium head for the small block six that is promising. Flow bench numbers are in the range of GT40 heads for the small block 8's. Better yet, the head for the big block six is being worked on by the designer. Expect prototypes in 18 months to a year based on the developement cycle for the small block.

 

Hmm, interesting. I don't plan on doing any wild modifying for a while, but's it's always nice to know that I potentially could. Thanks for the comments.

 

The topic of a crossflow head has come up fairly often, but I have to say that I have yet to see a shred of evidence that it will work better than the stock head just because it is crossflow. If you look at the pros and cons of the crossflow head vs. stock I think you will find that the only adavantage the crossflow has is that it separates the intake ports from the heat of the exhaust ports. 10 years ago that was a big deal. Now days you can apply thermal barrier coatings to both ports and be in great shape.

The crossflow head brings with it some serious compromises. Possibly the biggest is getting the intake ports around the pushrods. This is the biggest hurdle to intake flow. Pro engine builders spend lots of time and money moving pushrod holes around to make the intake ports bigger. Another problem that comes to mind is the angle to the valve within the port. Unless the valves are canted significantly, either the exhaust or the intake will have to make a big turn in the port because the valves are leaning towards one port and away from the other. In the stock head that isn't a problem. Both valves are leaning towards the port, so neither port is handicapped by making a huge turn. There is no doubt that the stock head isn't very good in stock trim, but it has the potential by it's basic design to perform very well.

 

One of the big advantages of a crossflow over the stock head is that you can have much larger ports because there isn't the opposing port take up the space. That provides the ability to overcome any interferance from the needed area for the pushrods. If this weren't the case then V heads would no longer be crossflow designs.

 

I disagree that the ports get in each other's way. For all practical purposes they have unlimited space in stock form. They only interfere with each other on one side. The other three sides are free to go anywhere they want. V engines are crossflow because there is no other practical arrangement for getting air in and out of the engine.