I was reading the post about fabbed radiator supports the other day and it got me thinking. Do I need a bar between my frame rails under the radiator?
I figured the K frame, bumper, and the strut bars (when I get them on) would keep the rails from moving? The original radiator support was all smashed and had no strength anyway, so I cut it off. If I need a brace, I want to weld it on before I paint next weekend.

I would say yes, but IJMO, the K frame looks like it would be easy to twist.

I'm not a chassis guy, but I stayed at a Holiday Inn Express once ( ) IMO, I think you could benefit from a lower radiator support there. Between the lightened K-frame and the radiator mounted to the frame rail, I would put one in. As far as the design, XV motorsports has one for the later Abody that you could look at and make yourself.

Not to bum you out but I wouldnt mount the radiator
like that... if you get ant twist in the rails it
will tear the tanks open... I prefer to rubber mount
it

I did mine close to the way yours is in the pic , it did not last too long , split one side in half

I don't even think rubber mounts would help mounted like that.

Should I put rubber underneath the ears on the tanks, or completely cut the ears off and put mounts underneath?

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I would take them off and put a pair of rubber mounts
on the bottom and a pair on top

Ok. Did not realize it would do that. I'll cut the ears off and weld a brace under the radiator to mount it and tie the frame rails together. Glad I asked. I've got some money into this radiator getting the AN fittings and tabs welded on. I don't want to ruin it. Thank You.

As is its a no go for sure. Since you have the tabs welded on already. You could enlarge the hole to utilize rubber bushings like the ones that are on the end of your struts in the same pic.

Make it a relaxed fit and use rubber at the top and you should be fine as far as the rad goes.

Your K member looks extremely lightend. I would box those open ends in a bit more or definately weld a brace across the front of the frame rails. If not you will have a whole lot of twist going on IMO. mike

1st: I agree with the comments about supporting the rad in rubber.
The X-member is more difficult to design than to build.
A single piece of 2" solid bar stock across left to right seems like overkill (it will work, just weigh too much) when in fact it doesn't resist anything except the rails separating or converging (out of parallel).
Controlling twist (racking) is almost entirely a function of the cross-sectional area of the X-member and its attachment to the chassis.
The stiffest (most effective) would be something like 4" tall × 2" deep square tube with fairly thin walls.
Whatever you choose - it should have both height and depth (3-dimensional), with height more important.
Remember to make water drain holes in the lowest areas!

With out any rubber isolaters inbetween the radiator mounts and the radiator you might get a crack on the radiator tanks around the weld. I might put some kind of rubber mount under it, and maybee tie up the upper radiator some how. Just my opinion and I just posted I would never do that again...

OOps

unless you already have, I'd have the engine/trans installed along with water pump and fan/s for alignment.
are you going to install a roll bar and tubes to the frame rails under the hood?
nice looking project!

I have alredy done all the mock up with the motor, WP, and fans. I just pulled the motor back out to install the new radiator, re-do the support, put a glass hood on it, and re-paint the engine bay. This is what it looked like last year.

The motor is going back in in a couple weeks to get this thing back on the track. I think I'm going to put a piece of 1 1/2 round tube, bent in a "U" under the radiator welded under the frame rails. I'll weld blocks to the tube and put rubber between the blocks and the radiator. I will also mount rubber on the top. I will also brace the K member as mentioned. I had to cut it for oil pan clearance.