I'm still new here, and maybe many of you know all this, but I saw from one thread that at least a few of you might have need of it:

Everything you want to know about Ford sixes can be found on www.fordsix.com[/URL] , a good group of enthusiasts, racers, etc.. One of the first things they will recommend is that when rebuilding a 240/300, replace the phenolic camshaft drive gear with an aftermarket metal one. Also, there are better pistons available than the originals, which tended to crack, particularly in the 300 with its worse rod angularity (rod length to stroke ratio). You can rebuild your 300 with the longer 240 rods, but you need to go to the site for info on what special pistons to use. Oh, another also, if your 300 is a carbureted one, it has the open chamber, low compression smog head; get more power (esp. low-end torque) by switching to the later fuel injection head (high swirl) or, next best, the 240 head. If you do this, read the discussions on quench or squish (same thing) at Speed-O-Motive The fuel injected 300 has more efficient exhaust headers as well.

(Site hosts, if this post is superfluous, please delete it!)

(Uh, yeah, as I look further, over the 521 pages here, my little post would appear to be superfluous!!)

 

actually i found it interesting, i would think though that you would lose stroke with that mod.

most people go to an overhead cam to solve that problem with the timing, i just found out about that myself i did not realize they changed to a synthetic gear, so that is on my my list of to do's right now it runs fine but it only has about 125k miles or so, which is nothing an I6.

 

Although the other forum you mentioned is pretty good, and there are some very knowledgeable guys there, I found that the way they run it is like an 'good ol' boys' club. And that I found left a sour taste.

To anyone rebuilding one of these engines, I would say to steer clear of the EFI head. It is subject to cracking, a well-known fact, and finding one that is not cracked can be a daunting task in the J.yards. The desirable higher compression can be achieved by milling the head, and by using a higher compression piston, such as a hypereutectic from the EFI years. Coverting to a 240 head bumps your c.r. by about half a point. The 240 head can be identified by the bean or peanut shaped c.chambers.

Here is a 300 head/chamber with the over-size valves installed:

<a href="http://s659.photobucket.com/albums/uu316/bobbyrogue/?action=view&amp;current=P1010114.jpg" target="_blank"><img src="http://i659.photobucket.com/albums/uu316/bobbyrogue/P1010114.jpg" border="0" alt="chebby valves in a FORD??"></a>

And below is a 240 head. Note the shape of the chambers.

<a href="http://s659.photobucket.com/albums/uu316/bobbyrogue/?action=view&amp;current=240head2.jpg" target="_blank"><img src="http://i659.photobucket.com/albums/uu316/bobbyrogue/240head2.jpg" border="0" alt="Photobucket"></a>

Another option concerning c.r. and piston choice, is to have your block bored .060" over, and using 360 pistons to achieve the higher c.r.

<a href="http://s659.photobucket.com/albums/uu316/bobbyrogue/?action=view&amp;current=dishvsvrelief-1.jpg" target="_blank"><img src="http://i659.photobucket.com/albums/uu316/bobbyrogue/dishvsvrelief-1.jpg" border="0" alt="Photobucket"></a>

 

I thought the 360 was 4.050 bore stock. If that's the case, you would only need the block bored .050 over.

 

Changing rod length can't change stroke, Furius; the stroke is in the crank. And the camshaft gear was always phenolic, even on early 240s. Mine was good for 120,000 mi.. But most rebuilders buy a steel gear.

A long-running controversy, with knowledgable engine-builders and good arguments on both sides, concerns the rod-length to stroke ratio. If you have a 4" stroke and the length of the rod between the centers of each end is 8", you have a rod-length to stroke ratio of 2:1. Long ago, in the days of Model A's, Deusenburgs, and so forth, 2:1 ratios were thought by engineers to be the way to go. In more recent years, the ratios used have gotten shorter and shorter. This does not NECESSARILY mean that shorter rods are "better" in performance terms; we always have to be aware of all the compromises engineers must make. One of the constraints on engine design, surprisingly, is body style. For thirty or forty years, until very recently, car and even pickup truck stylists wanted lower and lower hoodlines. To get this requires lower and lower engines. If you build an engine with short rods, you don't have to have such a tall block. Unfortunately for us, the inline six (OHV, not flathead) is an inherantly tall engine. Mopar's answer was to tilt their I-6 to get the height down: the Slant Six. Everybody else started replacing their inline sixes with V-6s, which are lower . . . with some extra work. The few V-6s built before the modern era were 60-degree V-6s (60 degrees angle between the banks) because this was necessary for the engines to balance. But if you make a 90-degree V-6 it will be flatter and lower so you can have a stylishly low hoodline. Buick did this first, about 1965. Their old 225" V-6, later known as the "odd-fire" V-6, was an okay engine, but it was a shaker, especially at idle. About ten years (?) later Buick casting experts came up with a wierd-looking crank with split and offset rod journals that gave them a smooth-running 90-degree V-6, the "even fire" engine. We all thought that crank looked like a cobbled-up mess that would be prone to breaking, but in truth you could probably put 400hp through that crank. The Buick engineering team won an industry award that year; all of the other automakers in Detroit went to 90-degree even-fire V-6s, the stylists got their low hoodlines, . . . and the inline sixes disappeared, even though in almost every aspect except tallness, they were better engines than the V-6s that replaced them.

Anyway, you'll get lots of opinion for and against putting the longer 240 rods into a 300. It means extra work, and likely you'll notice little worthwhile difference. Most opinions are that long rods help a racemotor, where short rods favor a torquer, but you'll even get arguement on that. So unless it's a subject on which you have long-standing strong feelings, just forget about it and build the engine with its own rods.

Hey, you just taught me something, F250. For all the time I've spent B.S.ing with Sixers, I never heard about that cracking problem!! All I've had myself were 240 heads and smog heads. That info is VERY much appreciated . . . I've got feelers out for an EFI head. Maybe I'll forget that and continue with 240 heads as before. Thank you sir!!