Chassis Engineering Inc. founder Roy A. Lewis passed away Tues. October 17th, 2017.

Services will be Saturday October 21, 2017.

Visitation 10am, Celebration of Life 12pm.

Henderson Barker Funeral Home in West Branch, IA

He will be greatly missed by all who knew him.

AS-0305D Boxed Frame Universal Frame Adapter 3-5/8 inch

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Boxed Frame 3-5/8" Universal Frame Adapter

Chassis Engineering AS-0305D comes as a pair of universal frame adapters for Box-style frames.

box frame mount

These frame adapters work similar to AS-0304, except they come at a fixed length and only allows for a small amount of adjustment. These (AS-0305D) are 3 5/8 inch, measured from the edge to the center of the hole.

universal frame mount

chassis engineering frame mount

The AS-0305D is our most popular frame adapter because of its length. With a starting length of 3 5/8 inch, the frame mount can be trimmed down quite a bit, which makes it the most universal. If you are unsure of the length of the frame adapter you need, this is the best frame mount to choose.


Other lengths we have available for the AS-0305 frame adapters, which might eliminate the need for trimming the frame adapter:

Note: These adapters can only be trimmed slightly, so make sure to pick the length closest to your needs.


Important note: Because these are weld-on frame adapters, if the inner wall of your frame is thin or has holes, you may need to modify your frame by cutting a portion of the inner frame wall and replacing it with 3/16 inch steel to give it enough material for supporting your engine.


For best results, have a look at our engine mounts selection to find a matching set of mounts for your particular engine, and we recommend using our special, street rod-engineered SS-0011 engine cushion set with Thru Bolt Construction for safety, stability and durability.

SS-0011 Universal Engine Cushion Set
For some tips on engine mounting, have a look at our Common Sense Engine Mounts blog post, located here, and our One Technique for Engine Swapping blog post, located here. Both posts go into some detail on what comes into play when swapping/installing an engine, and should help in doing it right the first time.


Don't reinvent the wheel!


We have a large collection of complete engine mount kits for various car models. Before going the universal route, have a look at our collection here, link, and see if there is a swap kit for your car listed. If there is, use that kit instead.

If you can't find a kit for your particular car frame and engine combo, you can use the steps below to determine which parts you need.


Each engine mounting kit is made up of 3 parts:


1a. Frame adapters (link).

Boxed Frame 3-5/8" Universal Frame Adapter


Our universal frame adapters come in different styles.


  • For  channel-frame-small.jpg channel frames use AS-0106 (linkas-0106-small.jpg .
  • For  boxed-frame-small.jpg boxed frames use AS-0304 (linkas-0304-small.jpg or our most popular  AS-0305 (link) as-0305-small.jpg , which is available in 4 lengths.
  • For  top-hat-frame-chevy-small.jpg top hat frames (1936-1954 Chevy cars) use AS-0204 (link) as-0204-small.jpg


All of our universal frame adapters are adjustable and can be cut to the length needed to properly align the frame mounts with the engine mounts.

To determine the length of the frame adapters, use the information below to determine the frame width and the engine mount width:

  • If you are using a boxed-type frame, measure the distance on the inside of the frame between the boxing plates.
  • If you are using a channel-type frame, measure the distance on the inside of the frame between the side walls of the frame rails.

box-frame.jpg channel-frame.jpg

if you are using existing engine mounts, measure between the center points of the engine block mounting points, otherwise use the chart below to determine the width of the mounts you need.


Then simply substract the engine mount width from the frame width and divide it by two (for a frame adapter on each side of the frame).


We have a frame of 23 inches wide. According to the chart, we would use 19" engine mounts.

23 inches minus 19 inches leaves us with 4 inches, so the frame adapters would need to be (4 divided by 2) 2 inches long (from the edge to the center of the mounting hole).



Again, before you go the universal route, check and see if we have a full kit for your car and engine combination listed (link). If we do, it will save you some fabrication work.


1b. Engine Crossmembers (link) for use with wide frames.

Weld-On Engine Crossmember 8 inch Drop

For cars with a wide (26 inch or more) frame, we have engine crossmembers available, link.

We offer crossmembers with various drops. To determine which one would work best with your setup, locate the center line between the 2 engine mounts and place a flat strap across the bottom of the oil pan at this point. Then measure from here to the center of the crank shaft. This distance corresponds to the drop listed for the crossmember. Note: allow at least an extra 1/2 inch of clearance between the oil pan and the crossmember.

If you use our 19 inch engine mounts, our engine crossmembers can be used with any engine.


2. Engine mounts (link).


We offer engine mounts for a large variety of engines, in a number of different lengths to make them work with just about any frame type. 

The engine mount style is chosen based on the type (brand/model) of engine, and the engine mount length is determined by the width of the frame.


  • For boxed frames, measure the distance on the inside of the frame between the boxing plates:


  • For channel frames, measure the distance on the inside of the frame between the side walls of the frame rails.



To determine the length for the engine mount, measure between the center points of the engine block mounting points. Then use the information below to determine the length you need.


Note: If you are using one of our engine crossmembers instead of our frame adapters, use 19 inch engine mounts.


3. Engine Mount Cushion Set (link).

SS-0011 Universal Engine Cushion Set

For all the Chassis Engineering Engine Mounting Kits we use our biscuit style, streetrod-engineered SS-0011 engine cushion set (link).

This cushion set is impervious to gas and oil and offers great shock- and sound absorption as well as increased resistance to deformation and temperature extremes. It uses Thru Bolt Construction for safety and stability with a larger cross section to support even heavier engines.


2 Reviews Hide Reviews Show Reviews

  • 5
    Great Universal Engine Mounts

    Posted by John Lampo on 3rd Oct 2016

    These are simple and to the point mounts strong and well built. Thank you CE.

  • 4
    Heavy duty

    Posted by Jerry on 25th Feb 2015

    haven't installed yet