Hellraiser 3

Chassis Plans





Check out the Build Up

which will cover the build up of one of these chassis.

Estimated Chassis weight - 325 lbs

Guy Paananen's HR3 Chassis

Front mounted radiator.

8.1L, 4L80e & NP205 fit with minor mods to the sub frame.

2-28-11 Update

Decided to put the radiator in back.


My latest design is another 3 seater chassis.  It differs from my older 3 seater design in a few key areas, the biggest being the rear mounted radiator. With the radiator mounted in the back the chassis gains a sleeker appearance up front due to a lower hood line, this affords better front visibility as well as more potential suspension up travel. 

The passenger compartment is also few inches wider despite the overall width being narrower due to the elimination of the outer nerf bars. The seating arrangement places the rear child's seat in the center with entry and exit via the passenger window area. A mid-sized child seat (or such as a PRP Pre-teen) should also fit for future expansion. With some changes to the roof you should be able to get a full sized seat in back although you will want to modify the C-pillars for side entry.

The slightly larger size is more apparent when comparing this new 3 seater design to my older 4 seater designs (very similar to the BMP 3 seater).  Ample storage is provided via a basket above the rear mounted fuel cell as well as the areas to the left and right of the rear seat.

3 Seater overlayed onto the Hellrasier Pickup

Customizing the chassis is very straightforward and I note in the prints where certain dimensions effect important parameters such as chassis width, belly height, etc. I also feel this chassis would make an excellent 2 seater if you want a good go fast chassis with ample passenger space. Eliminating the rear set and moving the radiator up provides a ton of room for fluid coolers out back and the rear storage basket would make a nice platform for a spare tire holder.

Specs:  Outside of rocker to outside of rocker is 55.62", outside of door bar to outside of door bar is also 55.62".  Belly to highest point on the roof is 53.62" and length from front bumper to rear most tube is 139". Estimated chassis weight is 300-350lbs depending on bracing. The wheelbase shown is 110", I'd recommend sticking with 108-115" wheelbase.

As always some of the advantages of my designs include:

No bars near your head (unlike many homebuilt chassis designs).

A cockpit that is big enough to keep you from hanging outside of the chassis when seated.

A suspension that works excellent for both crawling and climbing. The exact suspension numbers I used can be found in my latest project buildup here (rear 4 link numbers) and here (front 4 link numbers). The FAQ talks more about this.

As a bonus I will be making available to purchasers of my plans the .dxf files for the suspension brackets and other water jet parts I had made (like the rear storage basket).  These can be given to a local laser or water jet cutter so you can work around the brackets like I did or you can try cutting them by hand.  I just ask that the files only be used by the end user and not distributed in any other form or used for financial gain.  I will include a link to the files with the chassis blueprints. 


Motors - As per the FAQ:

Short Block Chevy V8 w/ TH350 & Dana 300 Shown

Pretty much anything can be made to fit.  4 cylinders are no problem and most 60 degree V6's are actually more compact than a lot of the inline 4's currently out there (Suzuki 1.3/1.6, Toyota 2.4/2.7l, etc).  About the only engines that would give me pause are 90 degree V8's like a Ford 5.4L or 4.6L since they are so darn wide. That said It is easy to make adjustments to the chassis so if you did have a blown 5.4L and wanted it in the chassis you could as long as you were willing to put up with a wider front end.  Inline 6's present another problem - length.  You'd have to stretch the nose of each chassis a few inches (assuming a front mounted radiator) except for the BMP 2 seater which was designed with a Jeep 4.0l drive train in mind.

If you go with a rear mounted radiator you should be able to fit just about anything.

For reference my 3.8L/904/D300 is roughly 54" long (pulleys to rear output), 28" Tall (oil pan to top of motor) and 22" wide at the valve covers.

Axles: Whatever you desire.

Suspension: The skies the limit. I ran a dual triangulated 4 link front and rear utilizing 16" travel ORI struts and provide the numbers to duplicate this link setup. Wheelbase in the plans is approximately 110" and with 42" tires the belly is approximately 23" above the ground. The wheelbase and belly clearance can be changed to suit your needs. For further suspension information see the FAQ.  

The plans you will receive are laser printed on 11 x 17 sized sheets of paper.  I have broken down the entire chassis into stages and include a suggested order of assembly guide to help you build your chassis.  The guide lists how I would tackle the chassis build and notes when you should mock up major systems and suggests other systems that need to be considered at that stage.

Things to keep in mind:

1. I make no warranties of any kind for the performance or durability of this chassis.  You are buying plans only. If you chose to fabricate something using these plans you assume all risk in the fabrication and operation of the project.

2.  You will need a basic knowledge of tube bending and access to a tube bender, welder, chop saw, etc. Access to a plasma cutter or cutting torch would be very helpful but is not required.  The chassis is designed around 1 5/8 tubing with a bend radius of 4.5"***.  Larger tubing  or bend radii could be used with some adjustments to the initial tube lengths.  there are no bends over 90 degrees.

*** It has been brought to my attention that the 4.5" radius die is no longer available from JD2. See the FAQ here for information on compensating for different die sizes. It is actually a very quick and easy adjustment to accommodate larger bend radius dies.

3.  The plans are meant to be a guide.  Since there is no way to get the bends to match the plans %100 expect to have to make small adjustments.  The plans do have suggested cut lengths and start points for the bends.  It will be your responsibility to cope the tube ends.  In spots where there are straight braces I usually provide a recommended tube size and length, however in most cases your best bet is to measure the distance between the nodes to determine the actual cut length.

4.  The plans only cover the dimensions of the basic chassis.  This means gussets, mounting tabs, suspension related mounts on the axles, body panels, component mounts, and all interior mounting tubing, etc are your responsibility. You can use my buildups to fill in the blanks or to give you ideas.

5.  I will include a recommended list of material for the basic chassis.  You may want to purchase additional material if you would like to leave extra material on the cuts or if you feel you may have to re-do a section of tubing.

For costing purposes I used approximately (10) 20ft sticks of 1.50 x .120 DOM, and (3) 20ft sticks of the following: 1.50 x .120 and 1.00 x .095 for the main chassis bracing. To save money you can get away with using HREW for any piece of tubing that does not contact rocks. I will update this budget as I work thru my project, it contains the most accurate lists of costs I have seen yet on what goes into a buggy.

The plans cost $120 which includes all drawings on 11 x 17 paper; shipping is included in that price to any address in the Continental US.  I do not offer electronic versions. I accept Zelle as payment, email sales@azrockcrawler.com for payment information. I used to accept PayPal but as of 12/9/2020 I am no longer accepting payment from that "service".

All packages ship USPS, please allow 1-2 weeks for domestic orders although actual ship times are usually much faster.

International customers please read -

As of 10-30-2020 I will only ship to the US. I apologize for the inconvenience but I no longer have any faith in the postal services of other countries.

  Answers to the most common questions -

I do not offer an electronic version of the plans.

I do not accept PayPal for any orders as of 12-9-2020


Craig Woodridge's Hellraiser 3 Chassis