so if one wants to add some weight to the rear of the car, what do you use for weight? lead bars? how do you attach and where did you get the lead? thinking of bolting it to the struts near the rear of the fuel cell

I heard sum old school superstockers use to fill there bumpers with lead shot!!!!!
As far back as you can!

The BOUNTY 10.5 OUTLAW cars some are i know are getting wheel weights and malting them down in to blocks and put a hole in them and bolting them on the frame rails and roll bars right front of the back tires and up front on the frame and in the trunk but i know one guy that puts bags of corn in his car that"s funny but it works good luck.

The NHRA rule book desiginate how to attach permanent ballast, I have used 1inch by 12 inch wide steel plate as ballast I bolted it to the trunk floor underneath above the rear end housing, you should(if I'm remembering the rules correctly) use two half inch diameter bolts to mount permanent ballast, check the current rules before doing anything You can add a weight box also and put in removeable ballast in it also

Depending on how much you want to add & the car, you can also:
1. Melt lead into the tail lamp bezels.
2. Put a thick heavy plate under your trunk-mounted battery
3. Build a thick heavy battery box
4. Clamp a filled tube to the rear downbars, similar to a swing-out bar
5. Filled spare tire - sand, water, shot, whatever, put into the tire's valve stem hole, which is then plugged
6. Shot in the rear rails - requires provisions for filling & draining
7. Placing a thick/heavy disc in the spare tire well
8. A "protector" for the fuel tank

I have a 2 1/2" x 4" solid steel bar that I can mount in my trunk with 2 half inch bolts that run through the rear frame rails.

It weighs close to 100 lbs and kills just over a tenth of et. (.11)

I believe you're not allowed to run shot. What if it got out on the track, it would be like james bond.
I've always thought of a 6"x60"x1/2" plate sandwiched between the rear bumper and body...