Ford Truck Enthusiasts Forums

Ford Truck Enthusiasts Forums (
-   Big Block V8 - 385 Series (6.1/370, 7.0/429, 7.5/460) (
-   -   1996 F250 460 baseline dyno results and head porting info-RESULTS ARE IN! (

Boport 07-07-2010 09:42 PM

1996 F250 460 baseline dyno results and head porting info-RESULTS ARE IN!
Hi, I'm new to the site and thought I'd introduce myself and share some baseline dyno results with you guys. My name is Bo and I recently purchased a 1996 F250 crew cab 4X4 and love the truck! Used to have a powerstroke (which I understand is a bad word around here) and miss the mileage but there's something about this gasser truck I just love. Plans are to use the truck to tow a race car and boat around. I was pretty impressed with the stock power of this big block, truck seems to move out pretty well. But with anything, more power couldn't hurt especially being the majority of this truck's use will be towing. After some searching I discovered the factory air box noise reducer/restrictor and made quick removal of them with the band saw. Also installed a K&N element in the factory air box, removed the cat and installed a 2 chamber flowmaster muffler. With these quick and dirty mods completed, I'm amazed how much better the truck runs and how much more enjoyable it is to drive. I could really notice a difference with each mod. Now that the easy mods are done with though, it's time for some more!

I run a cylinder head porting shop that specializes mainly in the 2.3 ford 4 cylinders. I'm not here to promote my business or step on any toes, I just didn't see much (or any) before and after head porting results for these trucks and thought I would share what we find with others. I plan to remove the heads and freshen them up with a performance multi-angle valve job and perform some mild porting to the intake bowls and the exhaust ports. I don't have the heads off yet, but from what I have found searching these are the main areas of improvement on these stock castings. I plan to do a before and after flow test, along with a before and after dyno test to show any gains we have made (hope so at least!) I will also post pictures of the work on the heads we do for anyone curious or to help the DIY guys get an idea of what to do. I realize without larger injectors, headers, or other supporting mods the head flow improvements may not be all that great but we are going to do what we can and give it a shot. The engine has 140,000 on it and a good rebuild on the heads cant hurt anything even if we don't pick up the big power.

We dyno tested the truck today on the 'ol trusty dynojet chassis dyno down the street from us we use regularly for dyno work on the 4 bangers. Made 2 pulls that were within 1 hp and had identical torque so we stopped there. Peak power was [email protected] 3850rpm, and peak torque was [email protected]

Mods again if you didn't read above are:

Stock 140,000 1996 Ford F250 460
Intake silencer/restrictor removed
K&N air filter element in stock air box
Cat replaced with straight test pipe
3" flowmaster 2 chamber muffler dumped at axle

Here is the baseline dyno sheet (sorry torque line is hard to see-it's a crappy scan):

And here is the dyno mule!

33homerdoodle 07-08-2010 10:15 AM

Very interested in your after results. My 96 is virtually identical with 204,000 and appears to never been rebuilt. And a little down on power, about time to freshen it up. Where is that restrictor plate your talking about?

Boport 07-08-2010 12:49 PM

The silencer is a plastic piece located between the throttle body and air box that is connected to the 2 sets of rubber intake hoses. Take a hack saw to the "horns" leaving enough room to still re-connect the rubber hoses. I couldn't believe how restrictive it is, you will understand when you find it!

33homerdoodle 07-09-2010 01:49 PM

Wow, never thought to look in there. ID of each horn is about 1", pretty pathetic to feed a 460 some air. Hacksaw appointment tonight. Thanks for tip.

PatsPOS 07-09-2010 08:56 PM

Hiya Bo, and welcome! Got a request, I suppose. Is there any chance you can find an unmolested silencer in a junkyard and put it in your intake hoses for your next dyno pull, BEFORE you make any more mods? I know that logic dictates that a 460 with the silencer is like a marathon runner trying to breathe through a straw, but the "silencer vs. no silencer" debate comes up from time to time, and it's be nice to have some hard numbers to refer to. The reason I ask is a lot of guys swear to having a SOTP improvement (maybe because there's a bit more noise?) and others say they didn't notice a difference...and I don't recall anyone saying "I gained three-tenths at the track by cutting the silencer out." Since your truck seems to be pretty consistent, I'm thinking that if the silencer really is a restriction, it would show!

Considering how much dyno time costs, we'll understand completely if you decline! :D

dmanlyr 07-11-2010 08:09 PM

I, as well would be interested in starting with a stone stock engine / truck and going from there.

On my 1990 F250 with a 460 / E04D / 3.55 / stock size tires pulls a 14k trailer just fine in absolutly stock form. I rarely get above 34-3500 rpm, and even at that RPM it is still fast enough to get a speeding ticket here in WA state.

I would be interested as well in MILEAGE gains with the mods??

I would be be interested as well in a before / after DB (noise) changes as I am concerned with overall noise.

Here in Washington, we do get flooded roads from time to time, how does the removal of the factory water diverter afect operation in that case? Or is the factory diverter something that just does not work that well?

THanks, David

Boport 07-11-2010 10:58 PM

Thanks for the replies. We should have the heads off the truck tomorrow, got most of the way finished on Friday afternoon.

I do not have a factory silencer to re-install on the truck and my time on the dyno will be very limited. I'm trying to keep this project inexpensive and hourly rate on the dyno to perform a test like that (even as simple as it is) just isn't in the plans, hope you understand :(. If we had our own dyno here or the dyno time was free sure if someone sent me one, sure I'd be happy to test it.

In my opinion the silencer appered to be an obvious restriction to airflow (when comparing to the size of the throttle body and rest of the inlet tract) and I didn't want to take the chance of it hurting any results when we start increasing engine airflow further with the porting. My thinking was most enthusiasts that would consider porting the heads on their truck have already done the basic mods we have done prior and that is why we dyno'd the truck as we did with these minor mods.

I realize this application is not going to be relevant to every set-up out there, but for guys like myself that are just looking for a little more passing power while towing or to surprise a oil burner or two this seemed like the next logical "bang for the buck" path to take. The results will tell the story good or bad... so stay tuned!


mjp_t98 07-12-2010 04:07 PM

Is this a Speed Density or a Mass Air system?


Boport 07-12-2010 05:07 PM

Speed Density.

Boport 07-12-2010 11:11 PM

Got the heads off, taken apart and washed today and also managed to get some baseline flow testing done. We tested the heads as is, right off the truck (aside from basic cleaning). Here are the specs and the numbers:

Stock F3TE casting (EFI)
28" H2O depression
1/2" clay radius on intake, no pipe on exhaust
4.25" test bore
SF600 flow bench calibration

Valve Lift---IN Flow---EX Flow

You guys were not kidding about the poor exhaust flow, WOW. I put a test pipe on at .600" lift to see if the port really needed a pipe extension to work well and flow only jumped up another 7cfm to 148.8 I then began probing the port with a pitot tube to see what the velocity was doing and found a couple areas that could use some reshaping. I will give the heads a mild port job and see how the numbers respond. If that exhaust flow doesn't pick up to at least 70% of the intake flow after porting I am going to consider going to an oversized exhaust valve. I normally like around 80% intake:exhaust ratio and anything below 70 is really hurting power. Should have some initial results tomorrow evening and some pics. One neat feature Ford did was put a factory back-cut angle on the intake valve, looks about 30*. Good for the joe blow stock set-up, bad for guys like me looking for quick tricks for increased flow :) Stay tuned, and enjoy the pics.


DIYiT 07-12-2010 11:37 PM

I may not have an intimate understanding of how to interpret the flow numbers, but I can appreciate the amount of work you're going through to share this information with the community. Let me be one to thank you!

Boport 07-12-2010 11:48 PM

Hey thanks you are welcome. You guys have data based a lot of good info here that I have used so its my turn to contribute. Hell if this doesn't work there is always the blower option :-X04 . If you can find one....

Kiwi Petrol Head 07-13-2010 02:52 AM

Interesting stuff Boport - Thanks for your effort. We appreciate your input...
All of us have a ***** load to learn ... everyday. It's blokes like you that help.... Malo lava my friend.


Boport 07-13-2010 02:53 PM

Here's some before and after pics of the porting I have done so far.We are getting ready to machine the valve job right now and then I will blend things back in and run it on the flow bench to see how we did round 1. Enjoy the pics!

ceetwarrior 07-13-2010 09:41 PM


All times are GMT -5. The time now is 08:59 PM.