'76 F250 Turbo Build

jgavac

jgavac

Well-known member
Subscriber
Hey all!

I normally hang out over on the FTE forums, but when it comes to 300 knowledge it's hard to beat the crew here. Figured I would come hang out over here while building the 300 for my truck.

Brief background, I have a 1976 F250 4wd with a 300. Truck has been great to me for the last 7 years, but it lost all compression in cyl #1 during the past 5 years when I was in school (sitting for months on end). I have the original engine yanked out and almost all completely torn down, and I stabbed in a junkyard motor out of an '81 truck to get me by. I have a link in my signature to my FTE build thread for the whole truck if anyone is interested.

Now, for the meat and potatoes if you will. When I first planned to build the motor, I was just going to do a simple build with porting on the heads and MPFI. Then I thought I might build a NA motor to start, but then turbo it later. But now as I dig further and further into this, the more I think I'm just going to do a turbo build right from the get-go. Now, I'm not building a race motor that I want to rev to the moon. This is going in a 4wd truck with short gears and big tires, so I'm shooting for really strong midrange power with a quick spooling turbo for highway driving.

This will be my first full engine build, I've done top end builds and lots of other engine work, but never a full engine all at once. I've been researching for years and years in preparation, so I hope that I can get through this without too much trouble. I am always open to discussion and recommendations about the project, since plenty of you know way more than I do.

I'll start getting into the internals discussion in the next post.
Thanks!
-Jameson
 
Again, Welcome aboard Jameson.
What rpm range are you wanting to operate at?
 
pmuller9":3t5bb05j said:
Again, Welcome aboard Jameson.
What rpm range are you wanting to operate at?
Click to expand...

Thanks! Now that I'm in the right section :eek:opsie:

With my current tires and gearing, math puts me right in the 2600-3200 RPM range for 60-80 MPH. I'm considering gearing down in the future as well, so RPMs will slide north too.
 
So let's say good power to 4500 rpm at the most.
You can use the stock rods.
I recommend having the rods checked for cracks then remove the forging lines on the beams and have them shot peened then resized with ARP bolts.
The rods will look like this when complete.
https://www.dropbox.com/s/k9u6bhvzw0p5w ... .jpg?raw=1

Have Autotec make you a set of custom forged pistons to fit the stock rods and give you around an 8:1 compression ratio.
Those are Autotec pistons in the above picture.

Before you can order pistons the head will need to be completed first so you know the combustion chamber volume in order to figure the piston dish volume.

To make an easy turbo installation use the Ford 300 HD exhaust manifold.

This is Crowers turbo cam that works with the HD exhaust manifold for strong low to midrange power.
https://www.dropbox.com/s/qufkzkwyxoz8o ... .jpg?raw=1

If you are going to do MPFI you can use the Ford 4.9 EFI intake manifold.

Anything different from your initial plans?
 
That's some great info pmuller, because I was unsure about if forged rods would be needed. That was going to be a question for later on

Here's just my WIP list of internals, components, and work
-On pistons, I happened to find a Ross forged piston made for a 351W that has all matching specs except for the pin diameter. 4.030 bore (overbore on the block), 1.757 CH, 0.912 pin (These ones). I emailed them and the pin centerline is not offset. My only concern would be that it is a flat top piston, so controlling static and dynamic CR will be difficult.
-If I use the above ross pistons, I would bush down the connecting rods. Crower part number 90912 would require the connecting rod hole be taken up by 0.003", which there is plenty of meat for.
-If the ross pistons do not work, I am looking into custom pistons by either Ross or Autotec, and I'm planning to reach out to Scat and Weisco

-Machine head for oversized valves. I am undecided on if I will use the SI valves since they are only offered in stainless, or if I will stud the head and go with the longer chevy valves for potentially more options. I'd like to look for Inconel exhaust valves if possible
-I was told by a machine shop I have been talking to that Manley makes custom Inconel valves for around $40 a pop, which is a lot more affordable than I thought. I have not talked to them yet
-As mentioned above, I am considering switching to screw in 7/16" studs to open up the possibility of chevy rockers and valves. Undecided at the moment, but will be driven by what I end up doing for valves. Might still increase to 7/16" studs if I can get an appropriate rocker. Ideally want to go with roller rockers.

-On the cam, I haven't picked one out yet. I've been contemplating a custom roller grind like 81slantnosewp did for his build, but my budget might dictate that more than anything.

-For EFI, the plan was to utilize the lower plenum from an EFI motor, so I don't have to worry about getting injector bungs put in something. I need to do some more digging in this part of the forum, because I feel like I haven't seen anyone doing turbo on the MPFI setups. I've seen blow through carb and TBI, but not MPFI

-What's not mentioned above is I'm also wanting to go with a coil-near-plug ignition. I plan to run the motor using an MS3, which has support to drive individual coils. It can take a cam sensor input for timing, though crank position is still the preferred. I'd like to see if there's a cam sensor out there from another motor that might work down in the distributor hole that would also still drive the oil pump shaft. I feel like I've seen a sensor like that on transitional engines, but I may be conflating it with something else.


Sorry for the chaos :shock: I've had so many parts rattling around my brain the past few months.
 
Answering only your Ignition goals:--thesameguy

/viewtopic.php?f=7&t=67718


thesameguy ":3quuuf66 said:
Total cost:

Megajolt Controller, with pre-installed hard rev limiter and MAP sensor and programming cable: $200.00
EDIS-6 coil pack (Airtex part: 5C1123): $52
Bracket for coil pack (friend of a friend): $20
EDIS-6 module (Airtex part: 6H1107): $15 (@junkyard, $150+ new)
3x Spark Plug Wires (Denso part: 6716089 ): $45
Trigger wheel (Miller's Mule custom part): $120
VR Pickup (Standard Motor Products PC51): $25
Temp Sensor (Airtex part: 5S1018 ): $1 (@junkyard, $8 new)
Misc wiring (VR sensor, coil pack, EDIS module, temp sensor): $10 (junkyard, around $50 new as pigtails)

$488

I think this compares very favorably price-wise to other ignition solutions out there and offers the advantage of full programmability and temperature compensation. Time will tell how well it works, but I'm optimistic.
Click to expand...

honorable mention, the 2bbl TBi guys,

and jdlaugh430

viewtopic.php?t=75869




and jimmyv65

viewtopic.php?f=36&t=75700


and MPGMustang

viewtopic.php?t=68406



And why you should go MS2Extra, Mike1157 with BMW M3 throttle body ITP'S


ttps://www.fordsix.com/viewtopic.php?f= ... 13#p615713
xctasy":3quuuf66 said:
Okay. All that work has been done. ITB's are way easier! ITB's can be run bank fire (by alternating the injector sequence from odd to even), or sequential, but importantly, even if they have six injectors, they don't have to be port EFI with welded in or drilled in bungs. That makes a port on port set up hugely easier with MegaSquirt 2 or 3.

If going it alone, you need to find better people and companies who will work with you rather than guiding you down THEIR preferred path.

Choices are about what you want. In my humble opinion, side drafting an in line Ford small six is not a great idea. With side draft Webers, you cannot match the efficiency of a correctly set up & calibrated MAP system from an unleaded gas 185 to 216 hp 3.9 or 4 liter six from 1988 to 1993. They were down drafted in the 1984 to 1992 EFI x flow 4.1 liters, and then up-drafted for the 88 to 93 OHC sixes.

Since 1984 to 1997 in Australia, EECIV was Fords chosen way to integrate ignition, EFi and meet emissions and reliability requirements, without a MAF sensor, and just one really big 70 to 75 mm throttle body.


Moving to a Weber triple carb system, well, it can work fine, but probably not in a cramped engine bay like the Vintage In-lines intake and Falcon has. No real room exists.

Normally, switching to an aftermarket ecu will bring huge and completely unnecessary cost, both in hardware and tuning. Almost certainly won't drive as well as a stock Speed Density EECIV EFI from a 4 liter OHC Ford. Again, either V6, or the Australian 3.9 or 4 liter OHC from 1988 to 1993 always gives good results, and you can ITB it.

Since the USA just doesn't have as many hard core 4 liter in line six Fords, you have to decide if you want to triple Weber it or ITB EFi or go to some less than ideal stand in non port Throttle Body system (EZ EFI, FITECH, Holley Sniper et al ) which has a whole bunch of other issues, especially on an in line six.

a91what "SendMeUrDataLog" does it all for ITB's from base maps, and he's done everything with a M52 BMW ITB on Mike1157's 4.1 Maverick engine.
imag0065_zpsllunormt-jpg.614519


So that's everything from normally aspirated 3.2 liter to unturboed or turboed 4.1 liters. 195 cubes to 250 cubes, boosted or non boosted. Big cams or little ones.

The cross over point is easy, GM did it first with its speed density TBi for years and years. GM guys provided the 3 bar MAP sensor, the rest is easy.

Turbo

https://www.youtube.com/watch?v=RGvzTMlJ3-U
[bbvideo=560,315]https://www.youtube.com/watch?v=RGvzTMlJ3-U[/bbvideo]

Non turbo
https://www.youtube.com/watch?v=7T_tM-FYwnI

[bbvideo=560,315]https://www.youtube.com/watch?v=7T_tM-FYwnI[/bbvideo]

And the first day out with ITB'S and no turbo and an a91 what? Stevie MegaSquirt tune...

https://www.youtube.com/watch?time_cont ... b37v0Zb6lA
[bbvideo=560,315]https://www.youtube.com/watch?v=Vb37v0Zb6lA[/bbvideo]


Easy.

Three DCNF style ITB's from Jenvey or some ATB400's from DellOrto or Weber, and you don't even need anything other than a log head to mount it on.

ITB's are way easier than single throttle body systems.
Click to expand...
 
The stock rods are forged and will work fine if you are only planning on 10 to 12 lbs of boost if you rework them as previously described.
If you plan to push the boost for max torque then the BBC small journal rods are recommended.
https://www.summitracing.com/parts/cpi-b6385ds3b4ah.

How much boost are you planning on running?

Ross makes a nice piston for the money.
You are correct in that the one you posted will give you too high of a compression ratio.
You will need a piston with around a 30 cc dish to get the compression ratio in the low 8s.
Bushing the stock rods can be expensive. It would be more economical to get a custom piston to fit the rods as is.

You will want to install screw in studs no matter what.
The only roller rocker that has the right length for the correct geometry is the Harland Sharp roller rockers.
They come in both 3/8" and 7/16".

You don't need to spend over $1000 for a roller cam and lifters for a 4500 rpm engine and less than .500" valve lift.
The turbo Crower cam I posted is sufficient.

What are you planning to use for an exhaust manifold for the turbocharger?

I believe the MS3 can decode the PIP signal from the Ford 4.9 EFI distributor which contains both the trigger and cam sync signals.

If you decide to do a crank gear trigger signal you have the option of modifying either the Duraspark distributor for a magnetic cam sync signal or the later distributors for a hall effect cam sync signal.

In both cases a round flat cover could be made to replace the distributor cap.
 
xctasy":iic1l2lm said:
Answering only your Ignition goals:--thesameguy
Click to expand...

OOOh this is some good information. Thanks!

pmuller9":iic1l2lm said:
The stock rods are forged and will work fine if you are only planning on 10 to 12 lbs of boost if you rework them as previously described.

How much boost are you planning on running?

What are you planning to use for an exhaust manifold for the turbocharger?

I believe the MS3 can decode the PIP signal from the Ford 4.9 EFI distributor which contains both the trigger and cam sync signals.

If you decide to do a crank gear trigger signal you have the option of modifying either the Duraspark distributor for a magnetic cam sync signal or the later distributors for a hall effect cam sync signal.
Click to expand...

That's good to know about the rods, I was under the impression they were cast. In terms of boost, I'm not sure at this point. This is my first time building anything with a turbo, so I'm still researching how much boost to run and how to size the turbo. I was likely going to talk to some turbo mfg's at some point to see what they recommend.

For the exhaust manifold, I am undecided. I did a little digging around on the HD manifold, but there's only a couple of them on Ebay and they're listed for around $500, which I guess is the same as going rates for any aftermarket headers. I could do split EFI manifolds or a dual header with a custom 2-1 up-pipe made, but it might be a bit of hassle. I haven't decided either on where I want the turbo mounted; I had considered doing a low mount turbo which would make exhaust routing easier (especially doing a 2-1), but would add extra intake pipe. My concern then would be hitting it on something while off road, but as long as its mostly up above the frame I could make a skid pan. Alternatively, I bring it up and forward in the engine bay, which would make exhaust routing more difficult but give me a really short run to the intercooler. I'm concerned with clearances under the EFI lower intake.... I guess a lot is going to be driven by the physical size of the turbo.
 
you could try Stevens in Fort Worth for the hd manifold [image]http://www.stevensparts.com/images/LOGO.JPG[/image]
Probably get it for a bit less
 
The turbocharger size depends on the rpm range the engine will be run at. The head work and cam profile must also be matched for the expected power band.
Typically for low rpm applications you are looking at a single turbo with a compressor inducer size between 52 and 57 mm depending if the focus is on the low end or upper end of a power band below 4500 rpm.

Here is the lowest cost HD manifold that I know of.
https://www.ebay.com/itm/300-4-9-Ford-H ... SwmCVfUq8~

You can use it with a "J" pipe so there is an exit also for the wastegate.
download/file.php?id=3808&t=1

Here is a turbo set-up using the EFI exhaust manifolds.
viewtopic.php?p=635195#p635195

Here is a twin turbo set-up using two front EFI exhaust manifolds.
viewtopic.php?f=106&t=80555
https://canadianrodder.com/forum/index. ... ost-237657

If you do a low mount or rear mount turbocharger you will need a reliable oil pump to return the oil from the turbocharger back to the oil pan.

If you go coil near plug don't use junk yard parts for a turbo application. You need spark energy!
Use Holley COIL-NEAR-PLUG SMART COIL PART# 556-112.
 
Was the forum down for a while? I haven't been able to get on the website for over a week... But I digress.

The smart coils were the plan from the beginning.

In re: the oil pump, I recall seeing melling makes a high volume oil pump. Would something like that work, or would I be looking more towards an external oil pump similar to what you'd see on a dry sump system?

I'm getting ready to take the engine parts out to the machine shop, and there are a couple things I could use input on.. Namely, what to do with cylinder bore. At the bare minimum I would have it honed smooth, but since it's getting machined I'd have the option to over bore. Would there be any benefit (or risks) to running with a larger bore like 4.040 or 4.060 in a turbo build?

Thanks!
 
For turbocharging you want as much cylinder thickness as possible.
This means just bore enough to get the cylinder walls straight and round. Your machinist will determine this.
Usually a .030" overbore can get the job done.
 
MS3(as well as MS2)code is supposed to be able to decode the signature PIP signal for sequential injection and timing. For the 4.9L, this would be arguably the 1996 model year only, but i have yet to find someone who has used it on the 4.9l, only the more common V8 and don't know if it would cause a problem. *It looks like they dropped all support for signature PIP in the codes, so I wouldn't try it for sequential.

The 1996 balancer is made with a provision for a factory 4(or 3?) tooth tone wheel to bolt on, which is perfect for making a custom 32-1 wheel for and using a factory crank sensor and mount if wanted. You would have to run a serpentine belt setup though. There is no cam sensor that has been found to directly fit the 300 either, so if wanting to use sequential fuel or spark, a factory electronic distributor of any year would need to be used and modified for a simple single pulse per cam revolution. My choise is a TFI distributor for the hall effect vs VR sensor in a DS-II.

GM LS style coils are arguably the best choice, especially with MS3 logic level outputs. IGN 1A's are probably the most popular with MS, other than the cheap factory GM.
 
Been a hot minute since I have been able to really do anything on this project; Having to buy a new car took a bit of wind out of my sails.

But, I'm back at it. I'll be taking my block/crank/head into the machine shop next week.

Something I'm still trying to bottom out on is exhaust valves. Will the stainless steel valves that SI sells be sufficient, or do I need to be looking at having Inconel valves made? I know inconel is usually used in forced induction applications, but I'm not sure if the EGTs I should expect will be that high?


Thanks!
 
If you are doing the occasional boost run for passing or just for fun the stainless valve will be fine.
If you are going to work the engine under boost for towing or other HD applications where the engine will be under boost for long periods of time the inconel exhaust valve will certainly be more reliable.
In both cases be sure to install hard exhaust valve seats.

I talked with SI valves some years ago and at that time they had inconel valves that were not listed.
 
Little update;

My machine shop has been a bit busy, but I finally heard back late last week that my block, head, and crank have all been through cleaning and the block/head have been fluxed and cleared for build.

We're going to focus on cylinder head work first, specifically in the bowl so we can get a head volume soon and let me order pistons. While I'm still undecided on Inconel or SS exhaust valves, I figured I'd just go ahead and get the full SI valve set to get going and I can get Inconel later down the line.

On a side note, I placed my order for the oversized SI valve set through Vintage Inlines a couple weeks ago, but it's been kind of quiet out of VI. Does anyone know if they're still operating? I had emailed them a couple times prior and never got responses.

On the subject of valve seats, I'm open to recommendations on brand and material since I haven't done this before.
 
Usually your machinist orders the valve seats and does the installation.
You will only need to install exhaust seats.
The seat for a 1.60" valve is 1.630" OD and 1.375" ID and a .250" depth. (or close to those dimensions)
Those dimension was used in my last head
The Dura-Bond number for those dimensions is 30646 for the standard seat material.
If you want something tougher but is harder to machine Dura-Bond 70646

Having said that I'm sure your machinist has been installing SBC seats for the 1.600" exhaust valves for many years so just let him handle it.
 
Last edited:
For about the last month Matt has been in the hospital with COVID he just got out a few days ago.
 
bubba22349 said:
For about the last month Matt has been in the hospital with COVID he just got out a few days ago.
Click to expand...
That's what he was saying, I was able to get in touch with him a few days after this post. Glad to hear he made it through.

pmuller9 said:
Usually your machinist orders the valve seats and does the installation.
You will only need to install exhaust seats.
Having said that I'm sure your machinist has been installing SBC seats for the 1.600" exhaust valves for many years so just let him handle it.
Click to expand...
Fair enough lol. Since this is my first rodeo, why doesn't the intake need seats?

Related to VI, he had the intake valves in stock but none of the exhaust valves, and I guess SI is saying it could be a 3-4 months before they're able to make any more exhaust valves due to delays in getting their material. Anyone here by chance have some of those exhaust valve sitting around they'd be willing to part with...? 😅

Thanks!
 
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