New 4 Cylinder Engine Bare Block
Fits 41-53 Jeep & Willys with 4-134 L engine

New 4 Cylinder Engine Bare Block
Fits 41-53 Jeep & Willys with 4-134 L engine

New 4 Cylinder Engine Bare Block

Finally the 4-134 L engine has been reproduced!!

All machined surfaces are milled to original design specifications. Block includes: Valve guides; hardened valve seats, NPT threaded oil galley plugs, freeze plugs and camshaft expansion plug.

- Cylinder Bore: 3.1255 +/- .0005
- Valve Guide  Bore Diameter (In & Ex): .374 +/- .0005
- Valve Seat Surface Width: .09375? to .125 +/- .0005
- Tappet Bore Diameter: .626 +/- .0005
- Oil Galley Taps/Plugs:  NPT 1/8 & NPT 3/8
- Oil Galley Taps - Tapered

The machining operation is using automated CAD CNC machining with tolerances exceeding .0005 inches-far more precise and exceeding the tolerances of American-made '40s Willys engines.

Sample blocks were completely maped on a Coordinate Measuring Machine (CMM) and created a 3-D drawing in Solid Works to begin the process. The CMM factory used can measure up to 1.5 micrometers in accuracy (0.000059").

In effect, they reverse engineered the 4-134 L engine block and set it up as such. Instead of using a green sand casting as the original blocks were made, they used the investment cast method for more structural integrity and durability, as well as surface finish and machining surfaces, even though it is more expensive. In addition, the new grey iron blocks have a higher content of chromium and copper for added strength and durability over the original design.

About of the 4-134 L Engine Block / Warranty Information

Test Run Operations Log

YouTube Build Your Willys: Engine

Each block has an individual serial number.

They are each coated with a rust inhibitor and shipped in a wooden crate and come with a warranty and general prep information and each has an inspection tag with critical specs.

4-134 L engine  (GEAR TO GEAR)

41-45 MB
41-45 GPW
46-49 CJ-2A
49-53 CJ-3A
50-52 M38
46-49 Truck
46-49 Station Wagon
48-49 Jeepster


Item # Price

Availability: In stock

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Product Videos

4-134 L Head Engine Block Test Run

Questions & Answers

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Questions: Will the engine you’re working on for a 1954 CJ3B?
Question By: Chris on Jan 3 2019 4:33 PM
Yes, it would fit under the hood of a CJ-3B since this is a flat head and the CJ-3B had a high hood to accomodate the 4-134 F head motor.
Answer By: Willys Jeep Parts Tech on Jan 4 2019 5:41 AM
Questions: Do you know if there will be an engine bare block for the F-134 hurricane will be made?
Question By: Jax on Jun 10 2018 10:55 PM
Yes, we are currently working on it now. We are hoping to have it ready by the end of the year. Thanks
Answer By: Willys Jeep Parts Tech on Jun 11 2018 5:36 AM
Questions: What is the recommended oil wt. to be used with a built up Allied block? Can I use a synthetic?
Question By: Tom on Jun 3 2018 12:29 AM
We typically use non-detergent oil - 30 or 40. Thanks
Answer By: Admin on Jun 3 2018 4:50 AM
Questions: Is a price for complete engine l134.... long block disassembled.
Question By: Matthew walker on May 23 2018 2:17 PM
This price is as shown with the information above. It is a bare block.
Answer By: Willys Jeep Parts Tech on May 23 2018 8:11 AM
Questions: What is the weight of the bare block?
Question By: Mike on Sep 21 2017 3:54 PM
These blocks weight approx. 88#. Thanks!
Answer By: Willys Jeep Parts Tech on Sep 21 2017 10:57 AM
Questions: What is the cost of a complete L134 bolt on engine???
Question By: Luke Patrick on Sep 15 2017 2:49 AM
We have blocks, engine overhaul kits, crankshafts, camshafts, ect. Please call and ask for Mike M. I can work it up for you.
Answer By: Willys Jeep Parts Tech on Sep 15 2017 5:45 AM
This is a bare block motor. We can build it up with an engine overhaul kit and anything else you need. But the assembly of it you have to do from your location.
Answer By: Walter Andreis on Feb 6 2018 8:38 PM
Questions: What would be the total cost of all the parts needed to build a brand new engine with this engine block if purchased through you?
Question By: Frederic Ruiz-Ramon on Jun 9 2017 9:03 PM
Please call us toll free. There are a lot of variables there depending on what all you really need and currently have.
Answer By: Willys Jeep Parts Tech on Jun 12 2017 5:39 AM
Questions: Do you sell the gear drive front engine plate for this block? I want to do a reproduction gpw.
Question By: Mike on May 17 2017 11:41 PM
We can get those good used. Please call us toll free. The A1463 should bolt up as well.
Answer By: Willys Jeep Parts Tech on May 18 2017 6:04 AM
Questions: Are you going to do the same with the 4-134F engine?
Question By: Erick Vizcaíno on Apr 4 2017 9:09 PM
They are working on it now.
Answer By: Willys Jeep Parts Tech on Apr 5 2017 6:14 AM
Questions: It looks like this engine will fit a wide variety of military and civilian jeeps. How much does it differ from an original MB or GPW block and what additional parts are required to get a running operational block?
Question By: Josh on Apr 3 2017 6:25 PM
No answers yet. Be the first to answers the question!
Questions: Hello, The shipping price to Marseille in France ? Thank you. Mike.
Question By: MICHEL HESSMANN on Mar 23 2017 5:12 PM
Please email your full shipping address and the part number and quantities you need and we can quote you out. Thanks!
Answer By: Willys Jeep Parts Tech on Mar 23 2017 10:27 AM
Questions: what color was the engine painted originally from the factory?
Question By: jacob cabbage on Feb 28 2017 4:28 PM
Typically they were black if civilian and OD green if military.
Answer By: Willys Jeep Parts Tech on Feb 28 2017 10:11 AM
Questions: Will all of the original motor accessories, fuel pump, generator mounting bracket etc. for an 1952 M38 military jeep bolt on to this block with out additional modifications
Question By: Steven Casella on Feb 9 2017 1:32 PM
Yes, it will. This is a 4-134 L gear block.
Answer By: Willys Jeep Parts Tech on Feb 9 2017 5:42 AM
Questions: are the cam bearings installed?
Question By: peter on Feb 9 2017 10:38 AM
There is only 1 camshaft bearing on a 4-134, they are separate part number: 645595
Answer By: Willys Jeep Parts Tech on Feb 9 2017 5:41 AM
Questions: Can we now build a complete brand new l head with parts from your store? Can I get the vin number from my 3a stamped on my new block from the factory, this would allow me to have a number matching jeep? I could supply a copy of my motorized title and any other info needed. My stock engine was stolen during the rebuild.
Question By: j weber III on Feb 9 2017 1:52 AM
We can help you out with pretty much everything from start to finish. These are pre stamped at the factory, so you cannot get the numbers of your old engine put on.
Answer By: Willys Jeep Parts Tech on Feb 9 2017 5:38 AM