IH DT407 Head October 10, 2018 11:34AM
I have a hot farm IH 856. Still a 407. 10 mm A pump S300 3500 RPM.

I need more airflow as my stock head is restrictive. Can I put the head from a 1456 on and gain anything? I also have a stationary 407 that was in a crawler. It has a different casting number on it are they any different from the farm tractors?

With no intake manifold I know the 407 heads are hard to port and polish. Are there any shops who can tackle this in the Midwest?

Buckeye Binder

Re: IH DT407 Head October 10, 2018 12:32PM
Ive done some 407 heads and also cut the intakes off the outside of the runner is already large theres no difference in the heads ive done between the 361s or the 407s except for the valve size a 361 has a smaller valve because of the smaller boore you can go through the big freeze plugs in the intake for some access would your class allow you to make an intake ,Those are good heads just dont have any swirl

Re: IH DT407 Head October 10, 2018 01:16PM
With a s300 I highly doubt that you're head flow is a problem. Heavier valve springs maybe

Re: IH DT407 Head October 10, 2018 02:18PM
Lewis, I think you could cut the head and make an intake manifold. Rules don’t state anything about that.

DH966, how do I know how much head flow I need? Exhaust and intake. Are there calculations that I can use to figure this out? I don’t have an exhaust pressure or intake pressure gauge but I suppose that would be the place to start.

Re: IH DT407 Head October 10, 2018 02:58PM
A good cleanup at the most is all you need running that small turbo your short stroke is not helping at 3500 rpms those engines love rpms

Re: IH DT407 Head October 11, 2018 04:43AM
I guess I assumed airflow was my issue. I can never power out at the end of the track, always get under the turbo. Maybe it is exhaust flow? I get prolly 420 cc of fuel and smoke is black from start to finish. Just can’t seem to stay lit. Where would one start to correct this?

Would also like to stroke my engine. Class limit is 504.


Re: IH DT407 Head October 11, 2018 09:22AM
Got a pyrometer on it? What is your timing set at? If it's coal black, it's fat on fuel, you're snuffing it. The 361/407 heads have good airflow characteristics, they really don't need ported or opened up much until you go really big turbo or high RPM's.

Re: IH DT407 Head October 11, 2018 12:19PM
What size s300? Are you running water injection?

Re: IH DT407 Head October 11, 2018 01:22PM
What weight are you running?
What gear are you running?
What is the pump limit?
What is the turbo rule?

Re: IH DT407 Head October 11, 2018 03:29PM
Pyrometer runs 600 at idle
1700-1800 end of the track
Timing is 6 degrees
Was told stock timing allows for some lug at the end and the more we advanced it the less lug I would have? That was when we had a 450 Roosa tho.

2.6 inlet
2.89 exhaust I think?
Can’t run water injection
Would make 40-45 psi boost when I had gauge on it.

8500 lb
Run in hi 3 or 2 teeth under direct depending on track
Pump limit any size A pump
Turbo limit 3LM or S300 I believe need to check.

Re: IH DT407 Head October 11, 2018 11:51PM
Yes, timing a Roosamaster and an A pump are different, especially if the Roosamaster still has it's advance mechanism. I've had good luck with about 25 degrees timing on my A pump DT407.

Re: IH DT407 Head October 12, 2018 01:31AM
I think I’m confused on my timing. Need to find my bore scope and check it. So I want my EGT numbers up as heat drives the turbo?

So head flow is not an issue more than likely? I have probably 170 CFM intake and 160 exhaust???

What about stroke? How much can I add and would that help?

Re: IH DT407 Head October 12, 2018 02:54AM
A 2.6 inlit should be a s366 once you figure out your timing you will need more than 420 ccs of fuel. Also your exhaust housing will have a lot to do with how well it runs at the business end of the track

Re: IH DT407 Head October 12, 2018 03:13AM
I added a 1/2" of stroke to my 407, makes it a torquier engine. Takes some work to get it to swing past the camshaft.

I'd say once you know what your timing is truly set at, you'll have a good idea where to go from there.

Re: IH DT407 Head October 12, 2018 11:58PM
Tighter exhaust will spin turbo harder and pull down farther. It may also raise exhaust temp by
Added restriction to exhaust. Right now your timing being that retarded is not allowing
Your fuel to completely in the cylinder, keeping exhaust cold. Does it throw some cool flames?

Re: IH DT407 Head October 11, 2018 04:06PM
Timing a roosa master at 6 degrees is the end of injection and your timing an A pump
At 6 degrees for beginning of injection. That is WAY different. Not sure on how many degrees
Of injection duration a roosa master has to get in the ball park.

Re: IH DT407 Head October 11, 2018 04:30PM
We are not clear on the timing here. That could be your only issue. You should be mid 20s with an A pump and that would bring your EGT down IF your are in the 6 degree range.

Re: IH DT407 Head October 12, 2018 02:52PM
Thanks for the help. I need to get the timing figured out and start there.

Tighter exhaust housing? What are the drawbacks of that? Obviously the given flow now would push the charger harder if the housing was tighter.

Have a lot to work on this winter......

Re: IH DT407 Head October 13, 2018 02:55AM
Go to the dyno.

Re: IH DT407 Head January 03, 2019 03:06PM
BuckeyeBinder. Pm me if you’re looking for a higher flow head

Re: IH DT407 Head January 04, 2019 03:21PM
I haven't run a 407 since I was a kid. But we ran a Keith Underwood 450 rosa a 3lm off of a 1456 16 degrees timing. Always made 45# of boost at 4500rpm and a foot of fire. I have an attic full of trophies and a lot of found memories of those years

Re: IH DT407 Head January 08, 2019 02:48AM
What kind of CFM flow numbers can you get out of a 407 head thinking about building a dt361 3000 rpm tractor curious how much work does it take to change the intake and flow good numbers out of the head i am trying to decide if i want to go this route or build a dt360 motor


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