Top Chop Question....

[dwarner]

I failed to see a comment about wheel wells. Is it in this thread somewhere?

DW

[tortoise]

I failed to see a comment about wheel wells. Is it in this thread somewhere?

DW

In the post which drew your sarcasm about the top being aft of the cowl, I wrote "Also regarding Blowfish aero, isn't a comp coupe body pretty much anything goes forward of the cowl? Wouldn't it have been slicker to fully enclose the front wheel wells?"

Maybe I should have started a new thread.

[Sumner]

I'm still waiting for the new rulebook or I'd just look it up, but I'm sure the top chop rules are not the same for gas and altered coupes, and competition coupes. Can someone clarify this?

Here is what I think I know (from 2006 rules), but it might not be right, so take it with a grain of salt.

4.I Chopping -- The removal of metal from a body component in such a fashion as to
reduce the overall height of the component without changing the original shape at top or bottom.

4.K Contour --  Contour is........................contour.  In the special case of chopped tops, contour is considered to have been preserved as long as the angular relationship of the top to the body proper is not changed.

page 57 Vehicles competing in the Competition Coupe and Modified Sports classes must
have documentation showing the stock vehicle BEFORE modification.  (I don?t know
how many of us have that, but probably a good idea in case Dan and the guys don?t know what the vehicle looked like stock, Sum)

5.D.1 -- Comp coupes -- Other than chopping, no modification to the body is allowed
(cowl back I would assume).  Minimum vertical windshield height is 5? (I assume this is
the actually glass area).  The front and rear chop shall be equal.  Window openings may be covered by flat plates on the outside of the opening or left open. .......then there is more not related to the top.....except this.    Driver exit hatches in the roof are recommended, but shall not change the contour of the body (I would assume the top of the roof).

5.D.2 Altered Coupe  (I?ll skip a bunch here as 49 and up bodies can not be chopped) Pre -49 bodies may be chopped.  The chop shall be equal front to rear and must retain a vertical windshield height of at least 6? above the top of the cowl........ (so now we are not talking about the windshield?s height as above if I?m reading this right, but the height to the top of the glass above the cowl, a different animal...and continuing with the rule)......with a maximum horizontal length of 7? from the base of the windshield at the center of the car.  (the way I read this is that the windshield itself can be 5 inches in vertical height with the top of that 5 inches at least 6 inches above the cowl.  And in that 5 inch height it can be layed back so that the top is 7 inches back from the vertical at the top of the 5 inch windshield at the ?center of the car?.  Note I?m getting the 5 inches from 5.D.1 above.  So in 5.D.1. there was no mention of the angle of the windshield, but here it is added.  Does it also apply to the comp coupe car???)

5.D.4  Modified Sports --  (down in the 2nd paragraph one sentence) Coupe Tops may be chopped. (my guess is you follow rules 5.D.1 and/or 5.D.2.)

From the above I made a drawing for a friend and said I think this is what you can do:

   

This also shows what I think is legal with the spoiler and spill plates.

So Dan if you have time is the drawing above correct for Comp coupe,  Pre-49 Altered Coupe and Modified Sports Coupes???  Or are they different???

And the last question and this is pretty big.  Can the top be chopped above the windshield like where the arrow is above if it doesn't change the contour of the top of the top?  I've seen a couple cars that have been cut in that area and then the top has been perfectly flat, almost directly above the glass.

Thanks,

Sum

[tortoise]

I just read an article in Hot Rod about a car that suggested they raked the back window. I was wondering how they could have made this error when the rulebook seems clear on not modifying the contour of the vehicle behind the cowl.

Well, no, it ain't. Additional windshield rake is sure as hell a change in the contour of the vehicle behind the cowl, and is traditonally acceptable, although Sum's excerpt from the rule book says nothing about it in the comp coupe section. So if windshield rake is OK, what interpretation says rear window rake isn't?

[RICK]

I once had pictures of my cars body unchopped, then chopped. they were in 'BUILD DIARYS", but now they're gone??


  RICK

[dwarner]

It looks like I have gotten way over my head on this thread. I have never chopped a top and I am not current with all the problems and methods in doing so.

Let me finish this rule book and the other projects I am involved with that require a first of the year deadline and I will come up to speed. I will bring in some people to help me with the correct interputation of this rule.

I apologize to everyone for my attitude during the discussion on this thread.

DW

[Sumner]

I apologize to everyone for my attitude during the discussion on this thread.

DW

Don't think you need to apologize for anything Dan .  I think we all appreciate that someone so close to the rule making and interpreting is welling to get on here and be open to our views and open in sharing theirs.

Looks to me that your job and the 2 clubs job is pretty daunting and a lot of times doesn't seem to rewarding.  One reason I never considered running for public office.

Relax a little and get your "chores" done.

c ya,

Sum

[tortoise]

Sumner:
Look at the SCTA site, Bonneville 2006 pictures, August 11, cars 5, at the Hudson Boys cars. they have a stock bodied gas coupe and a competition coupe based on the same body. The comp coupe's windshield horizontal length is waaaay longer than 7", and the rear window is raked much more than the stocker. Record holder, presumably legal? I guess as long as the top above the windows is the same angle you're OK.

Mr. Warner:
Rereading the thread, it appears I'm the only one you gave any attitude to, and I repeat no offense was taken. Sarcasm and insults are a large part of the fun of this forum.

[Sumner]

Sumner:
Look at the SCTA site, Bonneville 2006 pictures, August 11, cars 5, at the Hudson Boys cars. they have a stock bodied gas coupe and a competition coupe based on the same body. The comp coupe's windshield horizontal length is waaaay longer than 7", and the rear window is raked much more than the stocker. Record holder, presumably legal? I guess as long as the top above the windows is the same angle you're OK.

     

 

Well the rules aren't real clear to me on this and I hope later when Dan has some time and can get some help they might be able to clear this up for us.  In the section of the rules where they talk about comp coupe they say "minimum vertical windshield height is 5".  The front and rear chop shall be equal."  There is no mention of the 7 inch horizontal at the 5 inch height, that is talked about in the Altered Coupe section, so the car above looks to be legal.  Even in the altered section the windshield can be longer than 7 inches along as it is not laid back over 7 inches in a vertical 5 inch height.  Also the car above looks to have equal chops front and back, which keeps the top of the roof parallel to it's original location and thus does not drop the back of the roof which could offer and aero advantage.  I looked at the cars while we were waiting in staging and they are nice cars and the comp coupe one did set a record during speed week.  I've also watched their lakester over the years and watched it morph into a rear-engined roadster (neat idea).  This is a great team.

Now the quote you referred to earlier:

I just read an article in Hot Rod about a car that suggested they raked the back window.

 

I feel the poster was referring to not really the rake of the back window, but the new rake of the top of the roof itself (I hope they correct me if I'm wrong).   If the article is correct it sounded like they left the very back of the sail panel in place and rotated the back roof sail panels down into the body when they chopped the front, so it sounds like they didn't chop the back of the roof.  If this is so with the original shape of that car's roof it would result in a new, "non-parallel", position of the top of the roof in relation to it's original position.  Hard to describe unless you have chopped some roofs.

The other thing is almost always you end up changing the rake of the front and/or rear window when you chop a vehicle, especially a vehicle later than the 30's.  If the A and C pillars are not straight up and down if you chop the roof and leave the top of the roof the same length you must slope either the front and/or rear pillars to get them to come together.  This was the reason for the rule in the first place to limit that lay-back that could take place, mainly in the front.  But if you angle one or the other or both you can still end up with the top parallel to it's original position (you haven't changed the contour of the top of the top that is also talked about in the rules).

Now a problem I see with interpreting the rules is that some of the new cars that you could use seem to already, "stock", have more lay back than the 7 inch horizontal in 5 inch vertical run.  Chop them and unless you add metal to the center of the roof across the car, which a lot of us do when we chop a top, the angle will even get more sever as in the car pictured above.  So the question is are you require to put angle back in, more than stock, of a late model car that comes with a lot of slope in the windshield stock???

I'm glad I don't have to decipher this in impound.  Dan you do have a tuff job!!  And I have probably just added more to the confusion .

c ya,

Sum

[tortoise]

The Hudson Boys windshield is about twice the rake of the 7/5 ratio allowed for altered coupes. There's no reason to think that rule should apply to comp coupe, any more than the chop rules for vintage gas coupe apply to altered. Gas coupe chops must maintain the original angles of both windhield and backlight, which usually requires both lengthening and widening the top.