347 in 1997 Mountiaineer, what do I need to know?

[bronchole]

My 5.0 has seen better days (212K miles) so I am looking to build a new motor for it. Since I do ALLOT of towing miles with it, I am considering building a 347 stroker for it. I believe that what I am after is an “off-idle” torque motor. All in by 5000 RPM is fine. It needs to be smogable in California though. I’m thinking of using a block from a 1996 Explorer I have from a motor that developed rod knock. Have the block gone thru and machined. Throw in a 347 kit and some aftermarket heads, a nice cam and go. I have Torque Monster headers on it. No muffler, but all 4 cats and ran all the way out to behind the rear tires seem to quiet it down. The lack of muffler has not been an issue with smog. They say the muffler is not part of the smog equipment so its not a problem. What else do I need to change/know? I would defiantly prefer to end up with something that will still pass the standard California smog testing. Pretty sure I will need to talk to Damper Dudes about a dapener for the 347. Will I require different injectors? MAF? Throttle body? ECM programming? Other stuff?


Things to consider because of the 347 build:

Harmonic Balancer:
Because 347 kits are primarily designed with the Mustang crowd in mind, they are all typically 28oz balance type. Our Explorer specific harmonic balancer is 50oz balance.
- Rework a 28oz harmonic balancer to work with the trigger for the Explorer. Probably not an option for this since I have not ran across anyone that has done this and retained the Explorer belt/pump system. I did see mention of a couple years of Cobra harmonic balancer that are more similar to the Explorer, but are balanced to 28oz.
- Re-balance the crank to work with the 50oz balance stuff. This option is interesting. From what I see some cranks do not have enough meat on them for this though. Will need to work with some local balance shops and see what they think.
- Have a custom harmonic balancer made that will work with the Explorer belt system and balanced for the 28oz crank.

Dampener sources:
ron at damper dudes Welcome to Damperdudes.net
Thier dampener specifically made to work with the Explorer front dress and ingnition trigger wheel, reballanced to 28oz:
PN: FO3024EX28OZ
(Just under $200 as of 8/2021)

Flexplate:
If I stick with the 28oz balance on the 347 crank, I will need a flexplate balanced to 28oz and the correct tooth count for my starter.

Injectors:
The increased displacement may end up running the stock injectors in excess of 80% duty cycle. If that happens I may have to change to a larger injector set. Since my build intent is not a high RPM build I might get away without this though.

MAF:
Larger injectors means something will need to happen here. Re-calibration or a matching MAF to the new injectors.

Fuel pump:
With larger injectors comes the possibility that I may have to supply more fuel, but not likely given the power curve I am looking to get.

Cam/vacuum:
I am looking to build a monster torque motor. I am hoping that I can achieve that with a cam that will still provide good vacuum at idle.

ECM tune:
In the end I am hoping that the motor can run acceptably without a tune. I believe it is possible to select matching injectors/MAF that would allow this. Of course to get optimal performance I will need a tune. Will need to discuss what strategies would work best with the tuner people.

Tuners:
don lasota a call or email at LaSota Racing Technologies


Here are some other 347 build related threads I am referencing:
347 question
5.0 347 swap
Stroking an Explorer 5.0L engine?

My rig description: Monsterneer

Motor builds that are inspiration:
"base" 5.0 engine: Ford 302 Base Engine 300HP Crate Engine

347's:
Fordstrokers
SMALL BLOCK FORD
FORD BluePrint Engines BP3474CT BluePrint Engines Ford 347 C.I.D. 415 HP Base Stroker Long Block Crate Engines | Summit Racing
CNC Small Block Ford 347 Stroker Street Engine, 390+ HP
BluePrint Engines 347CI Stroker Crate Engine | Small Block Ford Style | Longblock | Aluminum Heads | Roller Cam
347 Ford Small Block Stroker Crate Engine: F347-HR-C1
347 Stroker "Balboa"
Ford 347 Stroker Base Engine 410HP with Fox Body Oil Pan


Type of use:
Towing (85% of miles):
I do ALLOT of heavy towing with this rig. I tow a 8.5x16x7 enclosed aluminum trailer with it on long hauls anywhere from 150 miles one way to 1000 miles one way. The total load of the trailer is about 4500 pounds (trailer weight, SXS weight, camping gear, ice chest…). My rig weighs in at 5000 pounds when loaded for travel.

Wheeling (10% of miles):
I do off-road this rig when I am not towing with it. Always driven to the trails, never trailered.


Typical RPM’s:
70MPH in OD ~2300 (rarely in OD while towing. The 5.0 won’t pull it!)
70MPH in D ~2900

My power objective:
MONSTER TORQUE, high 300's from idle thru red line. 400 would be great.
HP..... whatever HP results from the torque curve I am looking for will be just fine. I'm not building this for HP, I'm building for torque.
Red line: all in by 5500 RMP or less!

Torque/HP curve desired.

 

[boominXplorer]

I'd put a cam / valve spings and roller rockers in it and call it a day. That alone with good exhaust really wakes up these trucks especially mid range. You start going 347 with aftermarket heads and so on your going to need to hit 3500 rpms to have more power than you have now down low.

Stock gt40p iron heads are way more durable than aftermarket aluminum and the swap doesn't gain as much power as you'd think. Nice cam setup will give you 40-60 hp gain since you already have exhaust to flow it.

 

[Gary Crist]

Alloy heads will let you run an extra point of compression w/o detonation fears.
Stick w/ smaller intake valves (1.90) intake. Think of a short cam and put 2 to 4 degrees
advance in when you degree it in. 24's and a MAF and you might get by w/o tune.

 

[vroomzoomboom]

you will want alum heads. trickflow and afr are the most popular, and a mls head gasket. you will also want to stay around 9 to 9.5 to 1 compression (you will also most likely have to use premium gas from this point on as well). cams, i would call a cam company, or tell you motor builder what you want to accomplish. maf, you can get away with a ford lighting 90mm. injectors, 32-42lbs as well as a fuel pump. with all of this, you will want to run a tune. give don lasota a call or email at LaSota Racing Technologies
ron at damper dudes is a great guy to deal with, i have one of his dampers coming to me, as well as had one repaired, and know another member that has purchased one from him.

 

[boominXplorer]

I feel like sure an aluminum top 347 might give plenty of power but once you start dicking with everything long term reliability starts to go out the window unless premium parts are used and the right person puts it together.

 

[Josh P]

How strict are the emissions numbers for this engine in california? It would suck to build the engine the way you want it to have it fail the load test on the rollers.

 

[Gary Crist]

I have a simple dumb question.....

How much torque or HP do you want to make?

 

[bronchole]

Thanks for all the input.

I'd put a cam / valve spings and roller rockers in it and call it a day. That alone with good exhaust really wakes up these trucks especially mid range. You start going 347 with aftermarket heads and so on your going to need to hit 3500 rpms to have more power than you have now down low.

Stock gt40p iron heads are way more durable than aftermarket aluminum and the swap doesn't gain as much power as you'd think. Nice cam setup will give you 40-60 hp gain since you already have exhaust to flow it.

The 96 motor is already a full roller motor from the factory. I am quite sure that just doing the cam and springs over a stock rebuild will be quite a bit more peppy than my 210K motor is now, but I'm pretty sure I will want a bit more grunt when pulling the trailer up grades. Currently I have to tack the motor up to 4500 RPM for several minutes at a time to pull the grades I am talking about with the tired old motor.

If I could hit the torque numbers I'd ;ike with worked over iron heads, I'd prefer that, but I think that is a bit beyond what stock casting heads can do.

I know from the 351W that I built for my Early Bronco that some Trick Flow TW heads and a cam can do allot. Makes pulling the front tires off the ground allot easier

 

[bronchole]

Alloy heads will let you run an extra point of compression w/o detonation fears.
Stick w/ smaller intake valves (1.90) intake. Think of a short cam and put 2 to 4 degrees
advance in when you degree it in. 24's and a MAF and you might get by w/o tune.

I am definatly considering aftermarket heads. For sure a specific and likely custom cam will be needed. The selection of both will need to be done as the final configuration comes together. They all need to play well with each other for the final song to play well.

 

[bronchole]

you will want alum heads. trickflow and afr are the most popular, and a mls head gasket. you will also want to stay around 9 to 9.5 to 1 compression (you will also most likely have to use premium gas from this point on as well). cams, i would call a cam company, or tell you motor builder what you want to accomplish. maf, you can get away with a ford lighting 90mm. injectors, 32-42lbs as well as a fuel pump. with all of this, you will want to run a tune. give don lasota a call or email at LaSota Racing Technologies
ron at damper dudes is a great guy to deal with, i have one of his dampers coming to me, as well as had one repaired, and know another member that has purchased one from him.

I am also considering Dart heads as well as a couple others. Need to work with the a builder to find the right combination.

Gas: I would like to stay out of using premium fuel, but if it is what is required then so be it. Its not the first thing I own that would need it....... In fact right now its the last thing I own that can take regular gas.

It's my understanding that since my desired build will not be tacking all that high (less than 5500 RPM red line) that I will not necessarily need to go with a monster MAF, although I may have to change injectors/fuel pump. Maybe a minor change in MAF..... But thanks for the input.

I suspect that to achieve optimal performance a tune will be needed, but I am unsure how a tune will impact the smog testing here in California. Can the tune be done Volkswagon style (sneak it in and it will work as long as they don't look too close)? Will I have to revert to stock tune for smog check? Can it run good enough on stock tune to pass smog?

Thanks for the tips on the tuner and dampener.

I'll add this info to the first post.

 

[vroomzoomboom]

if you change injectors, more then likely you wont be able to run a stock tune. the reason for that is your pcm will think you have 19's in it and pulse for that injector, and not for the larger ones so it will over fuel it. also, and if this isnt your first rodeo, if you change injectors, you would also have to recalibrate your maf to them as well.

 

[bronchole]

I feel like sure an aluminum top 347 might give plenty of power but once you start dicking with everything long term reliability starts to go out the window unless premium parts are used and the right person puts it together.

Dicking with everything is what I do

Not sure why reliability would suffer. Unless you are referring to the rest of the driveline having to deal with the additional power. I feel confident that my driveline can handle 500HP and over 400ft/lb of torque, nothing in the driveline is "Explorer" except the transmission and motor. I;m running a 4406 transfer case and a F150 8.8 rear axle with a traction bar.

There is allot of "concerns" about the rod angle on a 347 stroker causing more wear on the cylinder walls resulting in less total engine life. The way I figure it, how hard I have to work the 5.0 to achieve the desired performance (4000 to 5000 RPM pulls for 10's of minutes up hills pulling the trailer) is also not a good way to have a motor live a long life. I am pretty set of going 347 unless it is going to be a smog nightmare or just not going to get the torque curve I am looking for. My hope is that with the stout torque curve I am looking to get I will not have to tack out the motor so much to achieve the same speed up the hills.

 

[bronchole]

How strict are the emissions numbers for this engine in california? It would suck to build the engine the way you want it to have it fail the load test on the rollers.

I don't know the exact numbers, but it does go on the rollers and if everything is not working right, it will not pass. O2 sensors, EGR hoses, all that crap needs to be working optimally in order for it to hit the numbers. I have been using the same place for smogs since I got this rig. It is a test only place, they do not do repairs. The guys there are very helpful. It always passed until the last time. I had to do a couple of the O2 sensors, a new air filter and replace one of the hoses for the EGR system before they could get it to pass. If you think you could interpret the difficulty, I could go find the requirements?

 

[bronchole]

I have a simple dumb question.....

How much torque or HP do you want to make?

Power - Torque: If I was able to get in to the high 300's for torque to the wheels from idle on I think I would be pretty happy.

Power - HP: I am totally unconcerned about what the final HP numbers will be for this motor. It is whatever results from the torque curve I am aiming for.

 

[bronchole]

if you change injectors, more then likely you wont be able to run a stock tune. the reason for that is your pcm will think you have 19's in it and pulse for that injector, and not for the larger ones so it will over fuel it. also, and if this isnt your first rodeo, if you change injectors, you would also have to recalibrate your maf to them as well.

My Bronco has throttle body EFI on it so I am a little familiar with the rodeo, but nothing like I am sure you are. I was collecting stuff to do a Explorer upper based EFI on the Bronco, but I think I will just be going with a more modern throttle body type since they seem to have got them working pretty well.

AS for this build, ya it would need a re-cal or the matching cal MAF. Will need to go over this with whoever I use for the tune.

 

[bronchole]

I have a simple dumb question.....

How much torque or HP do you want to make?

Power - Torque: If I was able to get in to the high 300's for torque to the wheels from idle on I think I would be pretty happy.

Power - HP: I am totally unconcerned about what the final HP numbers will be for this motor. It is whatever results from the torque curve I am aiming for.

 

[bronchole]

OK, I am updating the first post with all the info provided by responses. Keep it coming!

 

[CDW6212R]

The CA smog check will be the hardest limitation. You should want to remove the rear cats, increase to 347 CI, raise the compression, tune required, heads need to be much bigger, cam custom to optimize everything, and enlarge the entire exhaust. That's a good game plan, the details are way harder.

If allowed, 2.5" cat pipes would be best for a 347 or 350hp level. Stock is already 300lbft, you should aim for 350+ at the wheels. There is no issue with rod lengths or side loads, ring oil usage etc, that is all very old myth, forget that. You could run regular fuel with maybe 9.7:1 compression, but only with a custom cam made specifically to achieve that. No OTS cam will do that, with OTS crap, plan on premium gas no matter what. With premium and the best custom cam, maybe 10.5:1 would work.

The stock heads are low performance, they flow under 190cfm. Most aftermarket will be 250cfm or more, the cheapest stuff will be 220cfm or so. A 347 needs more flow than a 302 to make great low rpm power. The GT40 heads on a 347 will make 302 power, it'll just be at a lower rpm. Some bargain heads cost $1000 that produce decent flow, in that 240cfm range. That should be the bare minimum to hunt for on a 347. I'd say those are the best deal for a towing SBF engine. More money can get you higher power levels, but at a much bigger cost per HP. Have the Intake ported fully top and bottom, a $300+ job should do well.

The gains would be limited by the exhaust flow, which as OEM, is horrible. Every part of the exhaust is terrible, very restrictive, and not good for any V8, let alone one for performance. If you improve the headers, great, but don't ignore the cat pipes or the mufflers, or the tail pipes. One muffler flows half as much as two, simply adding one stock muffler, doubles airflow there. Same for the tail pipe, one is not enough, it's fine for a 200CI engine, a 4cylinder, but not a V8, never has(100% of all EFI Mustang V8's have two mufflers and two tail pipes, same 2.25" size as the single exhaust Explorer). Two of most muffler will fit back there, the space is about three feet long, and 9" or more high, and wider. Two 2 1/4" mufflers and tail pipes re barely enough, the cat pipes should be at least 2.5" unless it's a stock engine.

Passing smog testing is about what they do test for, and having the combination tuned optimally. A basic tune chip device is not going to do well, a canned tune or base tune from a tuner won't pass. It will need a full tune by a good expert, and then it has to pass the visual stuff and OBDII computer checks etc. I know nothing about smog testing, other than I don't want to ever have to. Good luck with that.

 

[gmanpaint]

 

[CDW6212R]

Don't forget the transmission. It needs a much larger cooler than the stock one, way more than double stock. Find a long Super Duty cooler, from the early 2000's, the long version. That will fit in the front a little lower than the stock one. Install a temperature gauge too, keep the temps under 175 or so if possible. Add at least one external filter, I'd suggest two in parallel, one simple inline filter, and a bypass filter with a .060" restrictor in the line. I think that's the required hole size, thos filters are not made for full flow, it takes multiple passes for all fluid to go through them, because they remove everything down to 2-3 microns. With that you could replace the filters about once every two years at the most, longer if the ATF is premium and not getting dirty.