I'm gonna build an altered.

Rat Rods Rule

Help Support Rat Rods Rule:

This site may earn a commission from merchant affiliate links, including eBay, Amazon, and others.
And this

I have that patteren if you want to change them out.
I don't think it will be necessary, Ron, but thanks for the offer. I'll know more when we get into the build. When I laid everything out and looked at it, the straight in line plates will probably work just fine. Like we discussed, I had to start someplace when I ordered my parts from you, and the straight ones seemed right to me at the time. I'll let you know though. Your parts look great, you should consider going into business ! :p:D

Yesterday, for a little incentive, my Son Dan and I went to the drags at Bradenton. They were having some major meet there, and the cars were from all over the country. Even Bob Glidden's Son Bill was there. The cars were amazingly fast in the 1/8 mile..........some going slightly over 3 seconds at 200+ mph ! :eek: They were rocketships.

When you think about it, a super fast street car is considered fast when it goes 0-60 in under 4 seconds........these guys are going 0-200 in under 4 seconds in an 1/8 of a mile ! Luckily, there were no mishaps to speak of, one guy spun sideways at the start line and was able to drive back to the pits, and one Willys hit the wall lightly on the passenger side, but no injuries.

We crawled around under a lot of cars in the pits to get some ideas of how to set ours up, but those guys have more money in their center sections than I will have in my whole car. Fun to watch and look at though.

Its always fun to watch the big kids play. The races, car shows, cruises, sites like RRR, are all great resources. Always trying to learn something new.
Today my Son Dan and I went to the shop and our plan was to start sorting out what the rear suspension would look like. The first thing we did was slip the center section into the housing so we could put the pinion right in the center of my frame. Once we did that we removed the center section and made a simple jig out of 3/4 inch all thread to hold both of the housing mounts I got from Ron Pope in alignment with each other.

Here is what that looked like:

Then we inserted the housing into those mounts and slid it under the car to see how long we could make the four bar setup. We ended up that 16 inches long would be about right and we used some old four bars we had laying around to mock it all up. I didn't want to cut the 4 bars Ron sent me until we finalized the exact length.

I had to pester Ron a few times on the phone today for advice, and I also ordered a new set of frame plates from him. The straight ones would have worked, but the new arced set he is making will fit much better. This whole thing is a learning curve, and Ron has been very helpful and didn't hang up on me once ! :D (Sorry for all the calls, Ron :eek:)

We also decided to drop the frame down a couple of inches and everything lines up so much better with it lower. In this picture the rear end is just mocked up with everything unwelded, and using the scrap four bars. When the new stuff comes from Ron this week we can start welding it together and figuring out what the frame rear section will be like.

Doesn't look like much, but we actually sorted out a lot of issues today, and have a pretty good idea of how the frame will need to be to hold it all.


Are you planning to build the chassis to pass SFI Spec 10.3 (Center Steer Altered 7.50 and slower)?

I'm looking for some guidance or ideas on how best to do the X or K crossmembers they require and still clear the mandatory driveshaft tunnel and the transmission on my T bucket build.

Any help you can offer would be must appreciated.
Well, I'm not sure. I borrowed my Sons NHRA rule book one night and did some reading and took some notes, but I think the class I was looking at was something like 9.5 and slower.........but I am not sure. Is that different than what you are talking about ?

I figure this car at the most will run mid 10's, so that is what I am building it for, but I am still learning as I go, so maybe there is something I missed on that X member thing. Tell me more about it, please.

As long as you run slower than 9.99 you don't have to worry about it other than for personal safety. However, quoting from SFI spec 10.3:

{On cars with suspended rear ends, the lower frame rails shall be connected to each other between the rear axle housing and the motor plate by two floor cross-members of 1 1/4" x .058" or 1 1/8" x .065" or 1" x .083" tubing and a single diagonal of 3/4" x .058" tubing or an "X" or "K" member of 5/8" x .058" tubing. The forward-most floor cross member must be located 12" minimum from the rear floor cross member.}

Also note, from SFI 10.3:

{The frame rails shall incorporate one pair of tubular members per side. Single tubing members, for side rails, are NOT acceptable.}

{Frame rails shall not be reduced in size from the rear of the roll cage to a point 2" forward of the motor plate.}

All dimensions are for chrome moly tubing, mild steel OD dimensions are the same but the minimum wall thickness for all tubing is .118"

And there is a lot more, stipulating uprights, diagonals, suspension mounting requirements, etc. I strongly recommend that you spend the $38 and get the SFI specifications if your car even "might" dip into the 9's. Their number is (858) 451-8868.

Anyway, getting back to my question, this would all be fine except that "open drive lines passing any part of the driver's body must be completely enclosed in 1/8" minimum thickness steel plate securely mounted to the frame or frame structure". This, in our frame designs, makes the "X" impossible on the same plane as the lower frame rails (in our case, the 2" x 3" rectangular tubing). So, how do I satisfy the regulations and still keep the "look and feel" I am after? Any ideas? :)

You can see what I've done so far in my build thread "Sheets and Giggles".
Forgot to mention - having a midplate is mandatory on an altered.

From SFI 10.3:

{A full, one piece motor plate or the combination of a partial plate(s) at the rear of the engine block and an additional cross member is required.}
Yeah, I think that spec is for cars that run much faster than I intend. I am shooting for AT THE MOST a low 10 second car, and probably more like 10.5 seconds.

As for the driveshaft tunnel, I am going get a piece of steel tubing, about 6 or 8 inches in diameter, and have it split lengthwise so that it is half of that diameter. That will be the top part and will totally cover the driveshaft. Then I am going to run tubing down below it to totally encase the driveshaft in the event of it breaking.

I figure I will run the top part of that tunnel from in front of the transmission yoke all the way in back of the yoke on the rear end center section. I don't like the idea of a broken driveshaft whipping around between my legs ! :eek:

But I am totally learning as I go here, this is uncharted waters for me and my Sons. We've always done street cars, and they are easy compared to one that needs to meet rules.

I just got your email, Ron. My comcast email was not working for the past couple of days, couldn't open emails. I'll call you tomorrow with credit card info. Thanks for busting your tail for me.

Today Dan went to the steel supply shop and picked up some more 2 x 3 tubing so that we could spend the day figuring out just how the rear part of the frame needs to be to hold the 4 link setup. I got the new frame brackets I ordered from Ron at RPM, and also some 1.5 x .120 wall tubing from Applied Racing, so we pretty much had all the steel we needed to get going.

The design we ended up with is a little unorthodox and different from the street setups we have done, but it looks like it is going to work. The back end of these Bantams is so short it is hard to cram all the stuff under one that you need. In a lot of respects, I wish I had gone with my original plan to run a solid mounted rear, but this will handle much better, I'm sure.

Here is the mocked up result of our work today. The part that drops down under the frame is needed to let the lower bar lay parallel to the ground, so it drops down quite a bit. But we are going to run an 1.5 round tube out of that will curve up and join onto the bottom of the frame.

The two round holes in the lower part of the mount are for the round tubes I mentioned.......one will run forward to the bottom of the frame, and the other will run over to the other kickdown, into a similar hole in that part. We figure this should tie in the entire rear section pretty well, when all welded up.

Not much of what you see here is permanent, even the bars are scrap leftovers from another project, so it is all just mocked up to get an idea of how the final frame will look. But we did make major progress today, next week we can start prepping and welding it all up and then put it on the frame jig for final welding.

The last time I went down the track was about 15 years ago while I was in high school. I had a 76 Chevy truck with a mild 355. It ran a 10.25 1/8 with a 3:08 gear, stock converter and a 30" tire. Wish I had the money back then to fix all the "wrong" the truck had going on for drag racing lol.
Thanks, guys. Last night Dan and I went to the shop and revamped the kickup a little more. The things that are complicating this whole rear end setup are:

1) The lower bars of the four bar setup are so close to the ground, and

2) I don't want to cut too far into my wheel openings, I'd like to only cut slightly to keep most of the fender shape as is.

So, after some slicing and dicing, we were able to trim about 4 inches off of the height of the kickup (especially that part below the rails) and now it looks much better and sleeker. We also dropped the front frame rails down another inch from where they were.

I'm ending up with a lot of cut off pieces of 2 x 3 tubing laying all over the shop, but I think we are finally getting close to the final design. Dan has been a great help, he has a good eye and thinks things through very well. I hate taking all his time away from his own build, but he is being great about that.

Tomorrow I am going to cut some backers to slip into the frame sections for welding, and will post some pictures then.

Sometimes it takes major surgery and sometimes a little tweak here and there.
The project is lookin great!!!!!!!!!!!!!!!!!!!!!!!!!!
Thanks, Old Iron.

Holy crap !!!!! Today I went to the shop with the intentions of cutting some steel, but when I got there, this note greeted me: Mama Kitty is our resident stray cat that we feed every night, she eats then sleeps on her blanket while we work) :D

I thought Dan was working on his own car but he was working on welding up my rear sections ! I feel bad now because I came home from work and crashed, I should have been helping him, but I really appreciate him doing that for me.

The square part that hangs down will have a round tube going from it and curving upwards to the bottom of the frame. That will tie it all in and make it look better too.

I think from now on I'll just stay home, drink a beer, and let the car get built for me ! [cl

Last edited:

Latest posts