best body for road race setup

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momach

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New guy here, in fact I am considering my First A body.
I'm looking to build a street / road race small block.
Any input as to which body is best? It's between a post car with the shorter wheelbase and the pillarless with the longer wheelbase. The post car is likely a stronger body.
Hey, a few inches Does make a difference.
I know, that's what she said.
 
I'd avoid the pure fastback profile cars (Barracuda fastbacks and Dusters). They create lift in the rear at speed. A sedan profile with some flat deck in the back creates downforce.

Think about when nascar had the Thunderbirds kicking butt with Bill Elliot and then GM made those Aero Coupes. GM added the slanted rear window, but kept and short flat deck on the end. The T-birds had a similar thing already.

I like the 67-69 Barracuda Coupe because they have a rounded front nose and a flat rear deck. But the rear is sort of long. And it's a bummer the rear window is sunk in at the top.

I think 63-65 Valiants have promise because they are lighter and smaller packages.

....Nothing is perfect.
 
That's funny Steve, I was going to post the opposite. The reason is that the fastbacks have better weight distrubution and are more rigid to begin with. But you're point is very valid. So there's the pros and the cons. I think the final decision depends a lot on the class and type of racing.
The earlier As are about as light of a starting point as you can get. On the other hand, some of the E and Bs will get track width (which as fundemental of physics) and potential for better aero.
 
Mattax said:
That's funny Steve, I was going to post the opposite. The reason is that the fastbacks have better weight distrubution and are more rigid to begin with. But you're point is very valid. So there's the pros and the cons. I think the final decision depends a lot on the class and type of racing.
The earlier As are about as light of a starting point as you can get. On the other hand, some of the E and Bs will get track width (which as fundemental of physics) and potential for better aero.
Click to expand...

I think the fastbacks are less rigid. There is a open cavity in the middle of the crar. No diagonal braces, no crossbar/package tray, large non structural glass. The back area trim panels and fold down seats also add weight on top of the rear glass. Yes, that all helps the weight balance. But it's just adding rear weight up high. You could just as well add lead bars under the rear seat and get the same net effect.

66-67 Chargers had lousy aero in nascar. That straight fastback back just lifts the back. The coupe 66-67 satellites dominated them. For autocross aero is not really a factor. But on a road course at 120+ mph is.
 
Well when we compared back to back, Dave's early fastback (66 b-cuda) seemed at least as rigid as my notchback even though mine had connector and his didn't. We run the same tires and rims. I think there is a shaped channel up through the roof to make up for the lack of braces behind the back seat. You may recall that in my car, the floor where the bottom of those braces attached had to be rewelded and reinforced several times. OTH this may have as much to do with the quality of the original build as the design...

Again it comes down to the rules for the class. How much bracing and caging is allowed? Are aero devices allowed (vintage rules generally the answer is no)
 
You can use a duster, just put a direct connection style rear spoiler on. Those increase down force.
 
Depends on what kind of racing you're doing too. Aero won't matter at all for autocross. In fact, for anything under 100 mph it will pretty much be a non-issue, and even then you'd need sustained speeds over 100.

Smaller cars would be better for autocross, not as big a deal for road courses. Even A bodies are "big" on a lot of autocross courses.

Barracuda's like autoxcuda's are a good choice, small wheelbase and fit bigger tires than the Darts/Valiants. Dusters would be good too, probably the widest tires you can run on a stock A-body, you can get 275's all the way around without any modifications or cutting. Might be able to pull that off on a '67-69 barracuda, but you sure won't do it on a Dart/Valiant. And the non-fold down seat dusters have all the same rear bracing as everything else, so, fast back style body with bracing.

Overall, I think that the body style will make a lot less of a difference than the driver and suspension set up.
 
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