I am curious. I just did a search on our forum for this and couldn't find what I was looking for. In the past, the HD exhaust manifold which was used on large Ford trucks with the 300 six has been mentioned. Some have even compared the flow to the EFI manifolds, etc. From what I remember, it has a 2 1/2" outlet and was used by these trucks due to the fact they were run wide open, quite a bit [i.e. 3000+ rpms].

Some have mentioned a problem mounting the stock intake due to the reported fact that the HD exhaust has 4 holes (threaded) for attaching to the intake, where as the stock intake (and normal exhaust) use three mounted at different locations.

Stevens Specialty Engine Parts, in Fort Worth, TX, lists this HD manifold for 1965-1974 HD Ford trucks. Their part number is F7TE-9430 and they specify a 3 bolt flange [they may be referring to where the headpipe connects?]

So, has anyone actually ever installed one and if so, what were the results?

Thanks!

 

If I recall correctly, the HD Manifold had both a 3-bolt and a 4-bolt hookup to the intake. There's a lengthy discussion of it over on Fordsix.com

FORDSIX PERFORMANCE • View topic - 300 HD heavy duty exhaust manifold

 

Here it is:



And the flange side:



I live about three miles from Stevens and took a look at it prior to purchase. They say it is an exact replica of the original Ford part. I like the look and EFI exhaust manifolds are too easy.

If you need more pics let me know!

 

Looks like a nice piece! Should notice quite a boost over stock. Cool on being different too.

 

My exhaust manifold on my Ford 300 I6 looks precisely in every way like in your picture above but mine doesn't have any screw in plug facilty near the no. 6 cylinder side between the ribbing like your picture shows. Is mine a HD exhaust manifold?

 

The Ant, does the outlet pipe come STRAIGHT down?

The stock exhaust looks rather similar, but the outlet curves towards the rear.


If yours is straight, looks like yours has a HD manifold.

 

Woo hoo, mine comes straight down. Whats one of these engines with this manifold worth in good working order?

 

Whats one of these engines with this manifold worth in good working order?

In which country...

I'll trade U for a cross flow intake n head ($1500 s/h costs)...
No just B/S*^tting U.

 

Not sure if it's really "worth" anything. The HD manifolds were put on to just allow higher flowing exhaust, since the engines were usually revved a lot higher and for longer periods in the larger trucks they were put in. The engine's were pretty identical to their light duty truck counterparts.
If the manifold wasn't put on your engine by a previous owner, and you actually have an engine from a large work truck, there's a possibility you have a forged steel crank, which would be really nice. The manifold can be had for $200 new, and the crank is worth whatever someone will pay for it. But other than that, the engine's a standard 300 engine.

 

The engine came out of an Australian 1970 F-700 prime mover and was reconditioned to standard specs by Ford a few years ago which has a plaque on the side of the block stating so and has been sitting on a bench for 3 years when the truck was dismantled by its new owner. It did 2 years occasional work since being reconditioned and has a Turner 5 speed box. The guy I bought it off who dismantled the truck hasn't pulled it apart.

 

Sounds like a nice find. Personally, I'd love to have that in my truck, especially with the 5 speed transmission. There are very few, if any, five speed trannies readily available for a mechanical clutch. Most require a transmission from a newer truck that require a hydraulic clutch conversion.
Who knows, with a little luck, you may have the forged steel crank too. Not sure how to tell without opening it up and looking at it though.

 

Thanks. Is there somewhere on the forum where I can see all the specifications of the 300 engine? Can Australian heads be fitted to the 300 engine?

 

The Ant,

Thanks for the photos! "A picture is worth a 1000 words". Now, please keep us updated as you install it.

Abandoned Bronco,

Thanks for your input!

 

Australian heads be fitted to the 300 engine?

Why?
As cited above, I'm 'on' a site Down Under, a Falcon site (these motor grew out of a 144ci made to beat the early VW invasion 'Bug'). They have this motor in ALL it's current iterations and could help better from your geographic local. I know a 240 would fit but that's going 2 have drawbacks to what U NOW have. Here U may visit fordsix.com (I believe is the URL). Help with the other sites, guys...
Oh, our home page has the other appropriate forums here @ FTE (turboed etc).

 

That is so cool! I didn't think they exsisted.