Considering BP 331 Stroker over ATK 351

[Jamie Chriss]

I am getting close to having to make a decision on a new motor. I am open to all suggestion. I was originally going with a mildly built ATK 351 in the same price range as the 331 below. The Blue Print Stroker 331 motor below is being installed by Green Bean Bronco and it looks like a nice fit for a EB. The projected cost for the Stroker, new X15 and new transfer case is approx $9,500.00, then I need a good EFI system, Explorer front dress, 3G, radiator, mid to long headers, etc. I know Coyote fans are saying you could... but I have no idea how to source all the parts, I don't really see a plug and play option out there for lets say $12,500... I don't have the motor skills to piece together such a project.
>
331 Stroker - what EFI set up for all around use: 70 percent road, 30 percent
trails, exploring, light rock climbing, etc. I like the look of the old school Explorer EFI, but all the hoses and wires turn me off. I will spend money on really good stuff, this is a keeper EB for me.

Headers: questionis this motor going to be super loud with headers vs standard Ford manifolds. I think the best option is mid to long headers for a Bronco where torque is king? Then two into one exhaust.

Set Up:
X15 or simular manual transmission
32" BFG All Terrain Tires


BluePrint Engines 331CI Stroker Crate Engine | Small Block Ford Style | Longblock | Aluminum Heads | Roller Cam
$4,300.00

DESCRIPTION:
HP & Torque: 375 HP / 390 FT LBS
Compression Ratio: 9.7:1
Aluminum Heads
Hydraulic Roller Cam
Cast Steel Crank
Hypereutectic Pistons
BLOCK:
Hand picked seasoned block
Square and parallel decked
Align honed main bearing bore
Cylinders honed on computer controlled machine to within .0002 straightness and roundness
Cylinders are sonic tested for thickness
2-Bolt Main
4.000" Bored .040" Over
1-Piece Rear Main Seal
Mech fuel pump provision: Yes
ROTATING ASSEMBLY:
New BluePrint Cast steel crankshaft
3.250" Stroke
Forged I-beam 5.400" connecting rods
Hypereutectic pistons
28oz External balance
CYLINDER HEADS:
BluePrint Aluminum Cylinder Heads -HP9008
60cc chamber
2.02" intake/1.60" exhaust valves
190cc intake/65cc exhaust runners
CAM SPECS:
Cam Type: Roller
.543 Intake .554 Exhaust
218 Intake / 226 Exhaust duration
@ .050 - 112 degree lobe separation
IGNITION TIMING:
34 Degrees Total at 3500 RPM
ALSO INCLUDES:
Oil pan, Timing cover and valve covers
Brass Freeze Plugs
Dyno tested and shipped with results

 

[needabronco]

Trust me, anyone can build an engine. Frankly the flunky at ATK is a $12 an hour guy who installs parts and doesn't really care... YOU can build a much better mill in your garage with a few tools and some know how. AND boring a small block Ford "0.040 is a non starter for me, I wouldn't even consider it.

 

[Broncobowsher]

Intentionally boring a performance small block .040 over? That is not a good plan.

I've owned both a 351 and a 330" stoker (only a .020 overbore), the 351 is a much better Bronco engine. Put the same aluminum heads on the 351 will make it run great.

Want a really strong affordable small block? https://www.youtube.com/watch?v=p1w8OU_8-JM
Put it together yourself.

 

[bronconut73]

When you have a 260/289/302 torn apart right next to a 351W torn apart you really see how robust the 351W crank, main bearings and short block is.
Its also a long stroke small block. They easily make great low rpm torque.

My Grandfather once told me that if I did all the stuff I did to my 302 to a 351W it would suit a little 4x4 with big tires much better...
He then said its like all your Buddy's spending all that money on 305's in their Chevy Trucks. Yank that boat anchor and put those parts on a well built 4 bolt main 350. It was the early 80's, lol.

 

[Apogee]

I have a 351W, so I'm biased, but my mild 351W is plenty fun to drive and doesn't really have or need anything fancy to get me where I'm going. While the 289/302's get the job done, the added torque of the 351W really improves driveability IMO. For the types of dollars you're talking about, you could even consider a 393, 408, 418, etc, but then everything else will need an upgrade to keep up.

 

[Broncobowsher]

A properly built 351 (throw a little compression, some good heads and matched cam at it) and they run really good.

The problem I have is most of the 351 to 331/347 comparisons are comparing a stock 351 to a built 331/347. Of course a built smaller engine will run better. But throw the same parts at the 351 and it will run great as well.

A zippy engine is great in a lightweight vehicle. If you got the Bronco under 2500 pounds yes an engine that is lighter will be better. But with what a Bronco weighs, that little extra mass won't be noticed. But the extra strength will help. The 302 has a weak point in the thrust bearing is marginal. The 351 has a larger thrust bearing. I know of several thrust bearing failures in the 302 blocks, never heard of one in a 351 block.

Yes, the 351C crank has smaller bearings and is preferred for racing. That has more to do with high RPM bearing drag. Bearing drag is a factor at 10,000 RPM. But for a Bronco engine that turns half that speed it won't matter. Race motors only need to last as long as the race, thus a smaller bearing that lasts just long enough. Large bearings last a long time.

 

[sykanr0ng]

BTW, have you ever noticed I'll debate things when I'm on the fence about it myself?

A good way to get the arguments for or against to help you figure it out, isn't it?

 

[Dlish]

The other question in the OPs post, headers are going to help your performance vs the stock manifolds. If you are worried about noise it just comes down to muffler choice.

Space is tight under a bronco, I had long tube headers and it made accessing the transfer case impossible for oil change/check. Also were a problem when using long arms.

Currently have the BC Bronco shorty headers, Stainless Steel, ceramic coated, a little spendy but freaking awesome.


People seem to be having good luck with the throttle body EFI kits, FI Tech etc, I think they look pretty clean vs the mustang/explorer efi with hoses and wires everywhere.

 

[edmedlin]

My 302 from ATK dynoed at about the same specs as that 331. Most everything else is the same. Same heads, valve sizes and lift/duration on the roller cam. My heads are the Dart Pro-1 heads and they are fantastic.

 

[73azbronco]

331's are typically peppy mustang motors, designed to rev even faster. A 347 is more in line with a 351 because of the effectively longer crank approaching that of a 351, resulting in very similar torque and HP numbers. We have a guy or two here who has a 331 and loves it, but if your doing a 331, why not 347?

40 over is to much for a stroked motor unless you plan to burn the motor up doing 1/4 miles.

I have a 347, but in the end would have saved thousands going for a simple 351. I will say, a 302 based motor means it bolts right in with zero mods needed.

 

[BajaBronco]

I disagree with all the .040 being too much - it's too much if block ALREADY at .040 before bore and hone. Have it sonic checked if you are worried, but I've built several (4+) in the last 5 years and no problems with any. I've heard that on a 289 .040 is too much, but again, I've built one recently and have another in my Mustang that has 100k on it. Got hot when I ran the stock 4 blade fan, but hasn't been a problem since 98.
Also - I just built a motor similar to the original posting through a local machine shop. Decked, balanced, etc, using alum Edelbrock E street heads, intake, Comp cam, same comression, roller rockers, flat tappet cam, Mexican 302 (thicker mains) and paid around 4750 not including oil pan and timing cover - but those were leftover stock parts. Custom hand built locally is the way to go in my opinion

 

[Broncobowsher]

... I will say, a 302 based motor means it bolts right in with zero mods needed.

Should bolt right in. Most are based on a late model block, so there are a few little bugs that will creep in.

 

[Jamie Chriss]

ATK HP11C-EFI Ford 351W with FITECH EFI 390HP $6,500.00



ATK has introduced a new line of EFI engines based around FITECH'S NEW Self Learning EFI systems. This engine comes complete from Throttle body down to the oil pan. The only thing you will need is to supply your own fuel system (In Line, In Tank, or the FITECH Fuel Command Center). These engines are dyno tested with your EFI system and ready to go! Take advantage of the latest EFI for better drive ability, trouble free cold start, no tuning required regardless of elevation, driving habits and part swap!

• Horsepower: 390
• Torque: 420 lb/ft
• Block: Seasoned OE Roller Block
• Bore/Stroke: 4.040 x 3.500
• Displacement: 351W C.I.D.
• Crankshaft: OE Ford Cast 3.500" Stroke 1 Piece Seal Externally Balanced 28oz.
• Connecting Rods: OE Steel Rod 5.955" Stock Bolts
• Pistons: Hypereutectic
• Piston Rings: Moly Rings
• Compression Ratio: 9.8:1 Compression
• Camshaft: Hydraulic Roller
• Camshaft Specifications: 220/224 @050 .512in/.512ex 112LSA
• Camshaft Bearings: Installed & Clocked to OEM Position
• Cylinder Heads: Dart Pro 1 aluminum 58cc/170cc 2.02/1.60
• Freeze Plugs: Brass Installed & Sealed
• Rocker Arms: Billet aluminum full roller 1.6 ratio
• Oil Galley Plugs: Installed & Sealed
• Oil Pan: OE 5qt. Front Sump
Weight:430
Oil : 10W30
Oil Filter: Wix or K&N Recommended Per Your Application
Fuel Delivery : FITECH Go Street EFI 400HP
Intake Manifold : Weiand Stealth Dual Plane #8023
Spark Plugs : Autolite #3923
Spark Plug Gap : .035
Harmonic Balancer/Damper : Professional Products Externally Balanced 28oz Dual Bolt Pattern #80006
Flex Plate / Flywheel : Externally Balanced 28oz 164 Tooth
Timing : 34-36 Degrees Total
Water Pump : Standard Rotation Right Hand Inlet
Firing Order : 1 3 7 2 6 5 4 8
Exhaust : 1 5/8 Headers
Fuel System: FITECH Inline Electric fuel pump kit, Command Center or Custom In Tank Electric pump system (No fuel system provided)
Fuel : 91+ Octane
Ignition : Pro Billet RTR
Automatic Transmission Stall Converter : 2200-2500

 

[Dlish]

there ya go, 351 with Fitech, ready to go. Dart alum heads. maybe they will credit you for the stall converter since I thought you wanted a manual behind it.

 

[Jamie Chriss]

I currenty have a rebuilt C4, I am not interested in using it. I think I like the idea of a 5 spead manual? In my youth (23-30) I had a 1973 EB with a C4, it was easy to drive but it was never really exciting. I have saved enough money since my last EB, 24 years to do it right, problem is I still don't know enough about EB to make any real final decisions. I guess that is why I lean so heavy on this site. I am half way through a complete tub rebuild and need to wrap my brain around the suspension and engine set up.

Engine:
Heads:
Intake:
Cam:
Distributor:
EFI: Like the Edlebrock Pro 3, then Fitech, Holly Snipper
Front Dress: Explorer
Wiring: Painless
Alternator: 4G
Headers: BC SS Ceramic, Short
Trans: X15 or Better
Transfer Case: Atlas or Rebuilt Dana 20
EFI 23 Gal Tank:
Frame:Throttle Down
Body Mounts: 2" Billet WH or Duff
Front Supension: WH 2.5 progressive Spring
Radious Arm: Duff T Rex
Rear Suspension: WH 2.5
Shocks: Bilstein 7100
Rear End: Rebuild...
Front End: Rebuild GM W/Disc
SteeringBox: 4 Point Rebuild
Steering: 1Ton?
Exhaust: 2 into 1

 

[Dlish]

Tech article link
http://classicbroncos.com/tech/early-bronco-transmission-guide-manual-options

Awesome info. Lot depends on your use.
The atlas tc option is awesome, but do you need it? D20 holds up really well, wasy to rebuild etc.
and trans really depends on your use. Unlimited funds, the nv4500 is great, low granny gear and overdrive, but its expensive and uses a different crossmember etc. the toploaders are getting somewhat harder to find. Street cruiser the ax should hold up, but if you wheel it may e a np435.

Check the tech link above, and advance adapters has good write ups of most the tranmissions (strengths and weaknesses) as well.

 

[PCDan]

331's are typically peppy mustang motors, designed to rev even faster. A 347 is more in line with a 351 because of the effectively longer crank approaching that of a 351, resulting in very similar torque and HP numbers. We have a guy or two here who has a 331 and loves it, but if your doing a 331, why not 347?

40 over is to much for a stroked motor unless you plan to burn the motor up doing 1/4 miles.

I have a 347, but in the end would have saved thousands going for a simple 351. I will say, a 302 based motor means it bolts right in with zero mods needed.

I went with the BP 331 over the 347 because it has lower a compression ratio and delivers more torque than Hp @ 375/390, the 347 is @ 415/415 .

Don’t agree that 40 over is too much unless the compression is being blown up. JMO.

 

[surfer-b]

The one thing I see on the 351 that will need changed is the front sump oil pan, but that's no big deal, I'm sure they will swap it

 

[Broncobowsher]

If you ask, I bet they will build your engine with a rear sump pan.

 

[PCDan]

Tech article link
http://classicbroncos.com/tech/early-bronco-transmission-guide-manual-options

Awesome info. Lot depends on your use.
The atlas tc option is awesome, but do you need it? D20 holds up really well, wasy to rebuild etc.
and trans really depends on your use. Unlimited funds, the nv4500 is great, low granny gear and overdrive, but its expensive and uses a different crossmember etc. the toploaders are getting somewhat harder to find. Street cruiser the ax should hold up, but if you wheel it may e a np435.

Check the tech link above, and advance adapters has good write ups of most the tranmissions (strengths and weaknesses) as well.

For reference ICON goes with the AX15 behind a coyote