What's a better option. Using a convertible frame or boxing the stock one ? Any mods needed to make a vert frame fit a coupe ?

ALSO: will a 71 skylark vert frame fit a 1970 chevelle?

If done correctly at similar locations, boxing a frame yourself would be equal to using a convertible frame. There are no modifications required to use a convertible frame under a coupe body (though the coupe will lack the extra set of body mount brackets on the firewall that a convertible has).

What are the benifits of using a boxed frame if its not a convertible? Is it worth the trouble?

Unless you are building a rigid top fuel dragster, funny car, etc, you can never make a frame to strong!

I want to minimize flex on my car for better handling and and also reduce the movement of the body during driving.

So what convertibles frames can I use for my 70,,, ? 68-72 chevelle ? What about gto, skylark etc..

jfman,

Search around here some. I know that this topic has been disscussed before. I have boxed my frame and I was not all that pleased with the results compared to the effort involved. If you have the opertunity to use a convertable frame I would use it. This make the transmission crossmember mounting much easier.

I am pretty sure that I have some photos of mine on my website below. Check it out.

jfman,

Search around here some. I know that this topic has been disscussed before. I have boxed my frame and I was not all that pleased with the results compared to the effort involved. If you have the opertunity to use a convertable frame I would use it. This make the transmission crossmember mounting much easier.

I am pretty sure that I have some photos of mine on my website below. Check it out.

I did a search but all I could find was people arguing about boxing a coupe frame and using it on a convertible...

Any A-body frame will work, 68-72. And yes a skylark frame will work. The only part of a convert frame that is boxed is the center runners, other than that part the same.

I checked my Mitchell interchange, and both the 70 Chevelle and the '71 Skylark Convert use interchange #2548. You're good to go, now you just have to strip down 2 cars, and transfer everything. Sounds like a good weekend project http://bestsmileys.com/silly/5.gif

The reason you found people wanting to box a coupe frame for use on a convertible car is because convertible frames are very hard to come buy. You might want to analyse the cost for handling you hope to gain fromthe endevor of purchasing and SWAPPING in a new frame.

Drop in on the Pro Touring forum and compair your suspension with cars of the genre. Or just do the easy thing and put a roll cage in the car, that'll get you what you want AND add safety to your ride.

I did a search but all I could find was people arguing about boxing a coupe frame and using it on a convertible...

I just thought that I had written about this before. Maybe it was just me talking to the voices in my head.:wacko:

As I had said I did this to my frame and in the end it wasn't very impressive. Not that I can say that my car was 1 second faster a lap with it done verses not having it done, but I did a few simple tests before and after my frame was done.

First, I took my bare frame and set it on stands. The front stands we at the furthest forward body mount holes and I held the rear of the frame on the stands and then put a load on the very front of the frame and measured the amount of deflection in the front half of the frame. Now I did this by having three of my really big friends sit on the rear of the frame and one average size friend stand on the front of the frame. Not exactly scientific, but I at least used the same people for both tests. And what I saw was that the frame deflected about the same amount.

Second, with the car completely assembled I jacked up the front end from the front crossmember. When you do this, look and the body gap between the frotn fender and the door. It closes up quite a bit. It did the same before and after I boxed the frame. Again, not exactly scientific but I came to the same conclusion. The weak point of the A-body chassis to diflection is at the firewall line. The body and the frame are bolted together in enough places behind the firewall to support one another, and there is no real bridge to fill the gap between the front frame horn (where the major weight of the engine and transmission are placed and the major loads from the front suspension) and the rest of the chassis. To truely support the front horn you will need some sort of a cage with down tubes going through the firewall.

I agree that you can never make the frame too strong, I am saying that in my opinion that boxing the frame is not a good cost vs. benifit unless you are a profesional fabricator.

Happy New Year.

hmmmmm.... My stock frame is in excellent shape. Very little rust, looks better than 99% of the used frames I see on ebay. I might be better off keeping it the way it is.

I will keep looking for a vert frame but well see...