Using solid cab mounts on my pro-touring 69

[tranz am]

I'm at the point in my build where I will need some kind of cab mount. Im building this truck with drag racing / pro-touring in mind. I will have a fully boxed in frame and i will be installing a roll cage in the near future to further strengthen the truck, but not at the present time. My question here is will a boxed in frame be stiff enough alone to keep it from popping cab welds or cracking it if i use solid cab mounts? Since i plan to do a cage in the future and will be attaching it directly to the frame, I need my cab to stay put, thus the need for solid cab mounts. any input or experience with this would be great to hear. Thanks!

[tranz am]

I know a lot of people on this board frown on solid and even poly cab mounts, and a ton of you reading this probably feel this way. Because of this, it seam hard to find any info on anyone that's even used solids or where to find them, or how to make them. I know on 2nd gen Trans Am's and Camaros, aluminum body mounts are used quite often.

[PGSigns]

We ran the solid mounts any time we put in a cage. It just helps stiffen everything up. Not the best idea on a cruiser but for your application should work fine.
Jimmy

[tranz am]

Thanks jimmy, what solid bushings have you found to work? did you have to make them?

Originally Posted by PGSigns

We ran the solid mounts any time we put in a cage. It just helps stiffen everything up. Not the best idea on a cruiser but for your application should work fine.
Jimmy

['68 Newtricks]

You can compromise with poly mounts. I run them on my 85 blazer, plus the body is sandwiched between the roll cage and frame mounts. Little to no deflection while rock climbing, I can't see it in any pictures anyway. (bumper spacing) And I'm still running a regular frame.

[Keith Seymore]

I used solid aluminum mounts on my Chevelle (homemade pucks). Roughly 1000HP big block, 9.80 ETs naturally aspirated.

I think you will be fine in a truck application. Most of the twist on a pickup truck takes place between the cab and the box, not within the length of the cab itself (which is very short). You'll fix the cab/box twist problem when you put your cage in.

No need to compromise on poly mounts; There will be no degradation in noise/vibration/harshness with the solid mounts because that roll cage will be ALIVE with vibration (by being mounted directly to the frame).

K

[PGSigns]

We always made our own. Have a lathe and a mill in the shop so we make any part we can.
Jimmy

[Fatherof3]

Will the cage pass through the back of the cab into the box?

I like how this was done with spacer blocks between the cab and box bolting a rear sub structure into the cab cage

[Keith Seymore]

Originally Posted by Fatherof3

Will the cage pass through the back of the cab into the box?

I like how this was done with spacer blocks between the cab and box bolting a rear sub structure into the cab cage

Most guys go through the back window. Structurally "higher" is better.

Also - NHRA rules require the cage to be attached to the frame. Bolted to the box only would not be sufficient to pass tech.

K

[Fatherof3]

Originally Posted by Keith Seymore

Most guys go through the back window. Structurally "higher" is better.

Also - NHRA rules require the cage to be attached to the frame. Bolted to the box only would not be sufficient to pass tech.

K

That one was for autocross only and did bolt down into the rear frame

[tranz am]

My plans are to attach the cage directly to the frame and sandwich the cab with a plate and or flange. I will use 2 down tubes to the rear of the frame through the back window which will be lexan. The down tubes will mount where the coil-over bar and anti-roll bar support will come across.
I want to make the cage and cab able to be removed is desired.
So sounds like I should just grab some aluminum blocks and fabricate them myself.
The question left in my mind is how thick to make them?

[71Dragtruck]

I don't think the cage will pass NHRA inspection that way if that's something that concerns you or not, just a FYI to maybe look into.

I still have the rubber mounts, but my roll bar ties into the cab and the frame so it's pretty much solid mounted.

[tranz am]

I would definitely need it to pass inspection. I will look into this further. I am hopping that I can make it unbolt in some way. time to read the NHRA rule book again I guess.
do you have any pics on where the cage ties into the floor?

Originally Posted by 71Dragtruck

I don't think the cage will pass NHRA inspection that way if that's something that concerns you or not, just a FYI to maybe look into.

I still have the rubber mounts, but my roll bar ties into the cab and the frame so it's pretty much solid mounted.

[71Dragtruck]

My floor is all covered in carpet now, all I have are these real old pics from when I first put it in, they start at post #213

http://www.67-72chevytrucks.com/vboa...=203647&page=9

The inside back bars right behind the seats go through the floor and the top frame rail, welded to the top and bottom of the frame and then boxed in, the outside bars go to the floor and are attached to plates welded to the floor. The door bars also go to the floor and are welded to plates on the floor, the back bars go through the box floor, top frame rail, welded and boxed like my back bars.

[regan wilson]

IMO I would just build a good cage and forget about boxing the frame. It just isnt needed. I can put a jack under one side of my frame and see hardly any twist nor have I seen any in wheels up picks of it. I also have alum mounts.

[Tom Vogel]

[QUOTE=I am hopping that I can make it unbolt in some way. time to read the NHRA rule book again I guess.
QUOTE]
Im pretty sure you will have to weld it to the frame, thats how I remember reading it.

[Keith Seymore]

The exact verbiage, per General Regulation 4:10 is "All cars with an OEM frame must have roll bar welded or bolted to the frame".

There is not a specific statement in section 4:11 relative to roll cages, so I assume the intent is the same.

If you intend to take this truck down an NHRA track I recommend you design the cage with the rulebook in your lap.

K

[Keith Seymore]

Originally Posted by regan wilson

IMO I would just build a good cage and forget about boxing the frame. It just isnt needed. I can put a jack under one side of my frame and see hardly any twist nor have I seen any in wheels up picks of it. I also have alum mounts.

Agree. Truck frames are pretty stout, especially compared to a passenger car frame.

K

[Keith Seymore]

Originally Posted by tranz am

The only question left in my mind is how thick to make them?

The same thickness as the original rubber mounts.

K

[71Dragtruck]

Originally Posted by regan wilson

IMO I would just build a good cage and forget about boxing the frame. It just isnt needed. I can put a jack under one side of my frame and see hardly any twist nor have I seen any in wheels up picks of it. I also have alum mounts.

This^^

When I said boxed on mine where the bars go through I was talking just a square plate where the bar passes through.

[tranz am]

"Welded or bolted" I was thinking i would bolt a flat plate to the frame and weld the tube to that.

Originally Posted by Keith Seymore

The exact verbiage, per General Regulation 4:10 is "All cars with an OEM frame must have roll bar welded or bolted to the frame".

There is not a specific statement in section 4:11 relative to roll cages, so I assume the intent is the same.

If you intend to take this truck down an NHRA track I recommend you design the cage with the rulebook in your lap.

K

[tranz am]

yes but from what i remember arnt the bushings squished to a certain height? I dont have a bushing to reference. correct me if Im wrong but isnt there a steel spacer in there i could go off of?

Originally Posted by Keith Seymore

The same thickness as the original rubber mounts.

K

[tranz am]

Thanks for the link. I understand what you did there. looks good!

Originally Posted by 71Dragtruck

My floor is all covered in carpet now, all I have are these real old pics from when I first put it in, they start at post #213

http://www.67-72chevytrucks.com/vboa...=203647&page=9

The inside back bars right behind the seats go through the floor and the top frame rail, welded to the top and bottom of the frame and then boxed in, the outside bars go to the floor and are attached to plates welded to the floor. The door bars also go to the floor and are welded to plates on the floor, the back bars go through the box floor, top frame rail, welded and boxed like my back bars.

[tranz am]

thanks guys. I am going to see if maybe a local auto parts store has a new cab bushing I could look at for the correct height. I found where i can get round alum stock for cheep. about $20.

[GMR-PERFORMANCE]

Hockey pucks work very well for solid mounts.. Seen it many times.. Or look in to the off road body lift kits they have all sizes of spacers but again nothing more than a rubber puck.. Call it a lift kit or a hockey puck