We have a lot in store for Project Grandma this week. With the mini tubs all in, our fabricator Mike Ryan got ready to start on the Chassis Engineering roll cage. However, first we would need to build the frame rails to comply with the 25.5 spec that would make the car legal to 7.50 e.t.’s.

Granted, we expect the car to run in the 8.80’s with the 555 ci Pat Musi / Edelbrock pump gas big block going in between the frame rails, so 25.5 might be considered overkill. However, eventually we will go nuts and slide in our 427ci twin turbo LSX engine built by Billy Briggs, and we want this car to be able to handle it without having to add more cage later.

Before work on the Chassis Engineering cage could be started, we had to build the inner frame rails, and then tie-in the support for the stock suspension to take the brunt of the 1,100 to 1,300 hp engines.

Excuse our crappy lighting. First, Mike started with the cross-member. This is the cross bar runs between the frame rails, that dips down in the middle for the driveshaft. The cross bar was welded to two plates that Mike welded to the stock OEM outer perimeter frame rails.

Once the cross member was finished and tacked in, Mike added the two inner frame rails as required by SFI 25.5. We used 1-5/8 inch chrome moly supplied by Chassis.

Here is another shot of the inner frame rail. You can see that it is straight and then it curves forward to meet the frame rail at the front of the chassis. This will later by gusseted by the front cross bar and transmission x-member.

This is where the front frame rail intersects the frame. You can see the plates that Mike welded to the frame, and then the actual 1-5/8 chrome moly tubing to those plates.

This is where you need to be careful, and smart – with stock suspension. You can see the rear cross member here, and to the left the front frame rails moving forward. To the right is a bar welded from the lower control arm forward to the cross member which intersects the inner frame rail. Remember, lower control push while upper control arms pull. Mike is designing this chassis so that the lower arms force is directed squarely into the frame of the vehicle and not into the flex in the stock attachment points.

Here is the finished product so far with where the frame sites. Keep in mind, there are going to be additional bracing and gussets forward of the rear cross member. This is just the “bones” of the system so to speak. What will be added is the front cross member, front trans mount, a lower seat bar, and possibly an x-brace underneath the inner rails.

Since we started to get into the roll cage, you can check out the rear cross bar that was welded between the frame rails as the down points for the rear bars to come down from the main hoop. Of course, we’ll also use this to mount our fuel cells, battery mounts, parachute, etc.

Later this week we will be starting work on the roll cage. It should go in really smoothly given the fact that we are going to be using a Chassis Engineering 10 point moly cage and add a few bars to it to complete the 25.5 spec. It’s already pre-bent so that is saving us a lot of hassle!

One cool trick. We have a painted car (if you can call the original OEM 30 year old stuff on the body paint), and if we welded the tubs to to the body – even tack welds – we would melt the paint. So we are going to use seam sealer, but Mike added a few little gussets in the middle of the tub to keep it from deflecting. Pretty sweet. This will give them some support.

On a side note, our Publisher Lloyd Hunt showed Mike an easier, more stress relieving way to bend the tubing for the underside of the car – by using Editor Mark Gearhart’s face.