The effect of bigger engines on the body...

[ViperMan]

Hey guys,  I was reading some recent posts about 318-to-440(or Hemi) swaps, and basically what I was reading is, "it's pretty easy if you have all the parts - pretty much swap and go."  Of course, tranny is needed, driveshaft, rear, etc - all powertrain components, plus heavier springs/torsion bars, and radiator.  Of course, with all my research earlier in the year regarding my goal of a 318-to-440 swap, most of this I have already learned.

When I FIRST bought my 'cuda and started telling people about my "daydreams" for modifications due to come, I heard a lot of "you'll have to really beef up the body because the motor will twist it."

One guy started telling me where all kinds of new bracing has to be run and welded into place because a bigger, "torquier" motor will twist the body over time - especially if you're driving more enthusiastically.

Is there any truth to this?  I guess that from the get-go I was assuming I'd have to do this - running extra rails from the back of the firewall towards the rear of the car, bracing the front end, etc...

I was originally aiming for a 550hp mark with a stroked 440.  Now I'm thinking that with a 500 hp Viper, a 450hp goal out of the 'Cuda would be easier, cheaper, and just as much fun.  Would either of these builds stress the body like I've been told?  Obviously I have to make sure that the metal I already have is strong, in good shape, restored, etc...  But do I need MORE metal?

Need input... 

Jeff

[72hemi]

A set of torque boxes couldn't hurt or frame connectors. But my brother has a 73 Challenger with a 440 and the owner before him had a 440 in it and judging by the condition it was in when my brother got it the previous owner was pretty hard on it and it does not appear to have any twisting in the body. The car is pretty straight and I haven't seen any stress cracks or other flaws.

[Moparal]

Jeff, it isn't a real big deal for you. I don't believe you will be doing a lot of serious racing with 4500 stall speed, slicks, trans brake and the likes.

A good set of frame connectors will be what you want, then you can add the square plate leaf spring eye reinforcement plate on the front spring eye. This would be adequate for the fun times you were planning on for your car.

A drive shaft safety loop should always be included.  Keep your fuel lines away from the drive shaft tunnel.  Have some fun

[ViperMan]

Frame Connectors?  Torque Boxes?  Any pics of these items?

Thanks guys.

Jeff

[1970RTSE]

A lot of those comments come from folks who are a little ignorant on the e-bodies.  First, the body is the same whether or not the car was a /6 or a Hemi with a few exceptions.  There were torque boxes which bassically tie in the rockers to the vairous cross members.  Then there a a couple of other plates, but not a whole lot of difference.  Its not like you are stuffing a hemi into a late 70s Dodge colt or anything.  Any late 60s, early seventies chassy could use some stiffening.  Modern cars are something like 1000% stiffer than the old cars.  Helps with the noise, vibration and harshness (NVH) of the cars.

[Moparal]

Frame Connectors?  Torque Boxes?  Any pics of these items?

Thanks guys.

Jeff

Mopar performance has a st of bolt on frame connectors.  They do help to stiffen the car. You only have to drill 4 holes to apply them. Some weld them in after they bolt them on. Very easy install.   Also the square plates I'm refering to helps to stiffen the area where the 4 bolts for the front spring to bolt through. This is so you don't start stressing the area and tareing metal.  I have never run tq boxes on my cars, and they never had any.   The things I mentioned are in expensive, very helpful and easy to install. All bolt ons.  Frame connectors, plates, and driveshaft safety loop.

I will see if I can find you some pictures.   All I have ever owned is B and E body hot rods.  When you make power, the bodies can flex and loosen up the seams.  I say build your 550 hp engine and go for it

[72hemi]

The torque boxes I am refering to were factory on all convertibles, hemi's and 440 6 pack cars. Not sure if all R/T's and 'cudas had them or not, but definitely those I listed. If you check out PG Classic or BEA Parts they sell them, I think they run about $250 a set (sold in front and rear pairs).  Below is a picture of each. (I hope BEA doesn't mind me using their pictures)

[Moparal]

The torque boxes I am refering to were factory on all convertibles, hemi's and 440 6 pack cars. Not sure if all R/T's and 'cudas had them or not, but definitely those I listed. If you check out PG Classic or BEA Parts they sell them, I think they run about $250 a set (sold in front and rear pairs).  Below is a picture of each. (I hope BEA doesn't mind me using their pictures)

I agree, but he really doesnt need tq boxes, and they aren't an easy install either.   

[ViperMan]

I saw an earlier post of someone installing those.  I'm not really concerned with "ease," as I plan on getting welding tools, and have most of the grinders and such that I'd need.  But $250 a set?  They'd better be made out of gold...

Al, what's a "Frame connector" referenced above?  Any pictures?

Jeff

[GoodysGotaCuda]

I will certainly be upgrading my chassis for more rigidity when I upgrade the powerhouse. Very important!

[ntstlgl1970]

Side benefit of doing all this stuff is that the car will handle better and feel more solid driving down the road. Having a stiffer platform helps/makes the suspension work better. Some cars that have been really beat on can show cracking in the B pillar area where the rear window opening meets the quarter panel. Subframe connectors can be a pain to install but can help stiffen the car, likewise with the torque boxes etc. I think it's worth it. here are the XV connectors sitting on my hood before I installed them. These ones contour to the floor (well as good as 70's body fit anyway) but require tweaking/grinding to fit good enough to weld completely. Other styles don't get welded to the floor pan, only to the crossmemeber and rear frame rails. Others require cutting out the floor and welding in a section of box tubing. Whether one is better than the other is debateable and probably wouldn't be noticed unless you were autocrossing or road racing a lot.

Anything will help bolted in, welded in or whatever.

I think what sold me on putting something additional on the car was the XV video where they had the car on the 4 post machine and were twisting the chassis (I'm not promoting XV stuff over anyone else's) and you could see the difference in the resistance to twist after the braces were installed.

here is a video with some images of subframe connectors, although this guy is installing it wrong (car is supposed to be supported by suspension or secured to a frame jig during installation)

http://www.youtube.com/watch?v=31jJ5Q-z9mE