Help me understand the NHRA classes for an old Gasser

[Oldmopars]

So, I got a Dodge L700 truck kit, the one that comes with the 1940 Ford Coupe. It is an old Lindberg kit and, well it is needing a lot of love. So, I thought the best way to deal with this kit is to make it a Gasser. I have a bunch of Gasser parts from other kits that I built, or are building stock. (Revell 57 Ford Gasser, 58 Impala)

So, as I look at old pictures of 1940 Ford Gassers, I see B/G, B/GS, D/G, etc. I looked at the rule books and it basically says that, from what I can tell, it is going to be ?/G because it is a Gas class. But then it says weight divided by Displacement.  This is where I am getting a bit lost as I have no idea what this thing would weight. I plan to use a 454ci Chevy as of now.

Also, what is it when it is a ?/GS, what is the S for? Anything else I should know before I stick a Class on this?

[TarheelRick]

I will try to help with my limited knowledge.  First the /G and /GS difference; G indicates the engine is naturally aspirated (carbs, injected, etc.) whereas the /GS indicates the engine is supercharged. For the weight divided by displacement here is a link ( http://autohobbypage.com/specs/gen/ford40.html ) to the 40+ year Fords and it gives the weight of the stock vehicle.  However, when building a drag car weight is the enemy, so as much weight as legally possible is eliminated, therefore you may want to drop the weight by  two-three hundred pounds.  The rule book then will give you a letter designation for the class you would fit in. Hope this helps some.

[dwc43]

Cant help you with the classes, but you could always go post war circle track racing. I used the car from the same kit to make this one.

[Snake45]

Your '40 Ford with a Big Block Chevy would most like fall into either A/G or B/G, depending on how much weight was removed from it. My guess would probably be B/G, as the smaller, lighter Willys and Anglias were favored in A/G.

[iBorg]

A bit of a disagreement. Late 50s-early sixties, A/G. A B/G would be a small block. AA/G if you add a supercharger. Mid sixties, is when the Anglias and late models came in. It'd still be a legal A/G, just not competitive like the 409 Impala I was offered in '75 for $350. Still classed as a top of the class Super Stock but it couldn't compete with the hemi Darts. One of several bad auto investments I made.

[smhardesty]

Slight disagreement, Mike. Class designation for a gasser would never indicate whether a small block or big block was used. It would depend on the weight of the vehicle and the cubic inch displacement of the engine, not whether it was a small or big block.

 

Here are the rules for 1958 and for 1968. Gasser class rules changed pretty regularly through the years. You first need to decide what era/year you want you car to be, then check the rules for that year.

 

 

Edited October 5, 2018 by smhardesty

[Ace-Garageguy]

Easy answer: figure a 1940 Ford coupe stripped as far as possible for the old gas classes would weigh right near 2500 pounds.

EXAMPLE: according to the class breaks shown above, a non-blown 327 cu.in. Chebby engine would put you in A/G in 1958*, B/G in 1968 *.

* 2500 divided by 327 = 7.645. 

WITH A 454:   2500 divided by 454 = 5.5. That would be A/G in both years.

NOTE: decide what era your car is supposed to represent to get the right calss. ALSO: the 454 wasn't available in earlier years, but a virtually identical-appearing 396 or 427 could have been...and either could have also been bored and stroked to larger displacements.

NOTE 2: Class-legal weight reductions could be made by removing the front bumper and brackets, substituting lightweight bucket seats for the OEM, smaller, lighter light units in front and rear, a lighter battery, removing inner door and body stiffening structure, replacing side windows with plexiglass, upholstering with lightweight materials, etc. Components were often drilled to remove weight, and the maximum allowable 4" chop/channel would take weight out too. Later on, light fiberglass fenders and body panels were allowed by some sanctioning bodies.

Edited October 5, 2018 by Ace-Garageguy

[smhardesty]

 

Yep. Exactly Bill.

 

.

[Muncie]

but adding weight is also an option...  A certain amount of ballast was permitted.  Concealed ballast was prohibited, but there were ways...  I can remember the days when a buddy had a '57 Chevy that ran Gas class or Modified Production and weighed somewhere between 4,500 and 5,000 pounds with a very small small block.  

Racers always wanted to be at the low end of the weight break - for A/G, that would be as close to 5 pounds per cubic inch as possible to be competitive.    That makes it 2,270 pounds with a 454. 

More realistically, you could move that car into B/G with a 454 at 2,952 pounds and be more competitive.  A racer may even want to add more racing equipment (weight) and get into C/G at 3,632 pounds if there was a killer car already running in B/G.  Displacement can also be altered so the combinations start to multiply,

links to rule books here - 

 A general rule of thumb is every 100 pounds adds a tenth of a second to the ET so 200 pounds is a big disadvantage.

Anyways, that's a long way to say probably B/G (or if supercharged B/GS, BB/G, or BB/GS depending on the class designation in the rules for that year).  But it could be C, D, E...

My memory is failing on one important point. If I recall correctly, driver and fuel at the end of the run are included in the weight - adjust calculations accordingly.

hope this helps

[Oldmopars]

OK, this all helps a lot. I guess I need to nail down the engine for sure. I have a few options, the 454 is just one. I do have a Flat head, and the one from the kit, but I don't have any decent speed stuff for it. So, looking to go with a 60's era V8. Something that would be available in the early 60's, say 60-64ish.

I am not stuck on being extreme with the accuracy, but I do want it to be believable. 

At this point I am thinking a lower budget/weekend racer build. The kind of car you see the neighbor and his buddies building in the shop on the farm, then loading up on the farms L700 to take it to the race track. maybe something like the picture below. The kind of car I would have built if I was building it back in the early 60's, or a car my Dad and I would have built.

[Oldmopars]

I have decided that 1962 is the way to go. The rules allow for the open headers I want to run, and no bumpers required other than a push bar.  I will build it for B/G. I may use the 409 from the 58 Impala kit I have.

[Force]

NHRA changed the designations for supercharged cars in the Gas classes from the previous A/GS, B/GS and C/GS (A, B and C/Gas Supercharged) in 1966 to to AA/G, BB/G and CC/G.
The reason was to bring the class designations more in line with the rest of the classes where the double letter (AA, BB, CC) itself designated the class as a supercharged class.

Prior to 1969, Anglias, with their 90 inch wheelbase were only legal for the unblown gasser classes but was now legal as supercharged as NHRA changed the minimum wheelbase from 92 to 90 inches for supercharged cars.

Edited October 6, 2018 by Force

[Snake45]

13 hours ago, Oldmopars said:

I have decided that 1962 is the way to go. The rules allow for the open headers I want to run, and no bumpers required other than a push bar.  I will build it for B/G. I may use the 409 from the 58 Impala kit I have.

Sounds like a plan! 

[Reegs]

I asked this question in another forum but I would like confirmation:

H/G, I/G, J/G, K/G - only flatheads?

As with all things drag racing, the wording (to me, anyway) is open to interpretation.

Edited October 8, 2018 by Reegs

[Snake45]

35 minutes ago, Reegs said:

I asked this question in another forum but I would like confirmation:

H/G, I/G, J/G, K/G - only flatheads?

As with all things drag racing, the wording (to me, anyway) is open to interpretation.

Looking at the 1965 rulebook, it looks like G/G (5.00 to 10.99 #/ci) and H/G (11.00+ #/ci) are for "non-supercharged pre-1960 flathead V-8s, in-line 6 cylinder and straight 8 engines with stock production-type heads."

[Oldmopars]

So, now that I have been doing all this looking at the rule books to build this car, I know what the letters mean. However as I have been looking at models and other pictures on line, I am seeing models built with the wrong class markings and it is now bugging me, never did before.

I found a 58 Chevy with 409 and Hilborn Injection lettered as an A/GS-wrong.

Found this picture from Street Rodder Magazine called Anatomy of a Gasser, showing a blown engine and a C/G class, should be CC/G, C/GS, or even CC/GS depending on year.

I liked it better when I didn't know. These are only a small sample of the errors I have found.

[afx]

9 minutes ago, Oldmopars said:

I liked it better when I didn't know. 

 

"How fortunate the man with none"- Dead Can Dance

[Ace-Garageguy]

22 minutes ago, Oldmopars said:

 

...I liked it better when I didn't know. These are only a small sample of the errors I have found.

 

The world is a very different place when one is in possession of facts. 

Those of us who grew up around these cars can be driven to distraction by the incorrect info that's endlessly repeated by people who should know better...or just keep quiet.

Hopefully, you'll derive some pleasure knowing your work reasonably accurately reflects reality. To me, anyway, that's part of the "fun".  

Edited October 9, 2018 by Ace-Garageguy

[smhardesty]

Let me ask you something, Scott. Do you intend to enter this build in a contest/show somewhere where the rules state all details on the build must be correct or be disqualified? If not, why not relax a little and just get somewhere close on your class designation? There are a lot of unknowns in the scale world that wouldn't be on a 1:1 car. For instance and as stated previously, the car might be stripped of every once of weight legally possible, plus a few illegal pounds, OR as Muncie stated, the car might have had some weight added to push it into the next lower class, especially if it was close to the weight break but the motor was a bit weak for whatever reason.

As for finding "errors" in photos and drawings, there is too much unknown to be sure they are errors. The "Anatomy of a Gasser" is an artist's rendering for "Street Rodder" magazine. Maybe the artist just didn't know, or maybe it just slipped by him. And street rods don't necessarily depict an NHRA race car. 

Try this. Do an image search for "41 Willys gasser" in your search engine of choice. Then just browse through all the images noting the different class designations. Same car photo to photo, but you'll find lots of different classes.

Choose the year you want your car to depict, look at the rules for that year, locate the weight of your car on the 'Net, divide by the cubes, decide if your engine will be supercharged or not, then use the class designation from the table in the rulebook.

[Ace-Garageguy]

What gets tiring to those of us who actually know is things like the obviously non-supercharged cars running a blown class reg, or the endless repetition that the nose-high attitude is correct (based apparently on mis-interpretation of photos of in-period cars launching, or relying on photos of the equally endless stream of "nostalgia" cars built recently with their noses a mile high while at rest.

There is no excuse for the former. Supercharged vs. non-supercharged is pretty obvious, and it's nothing to do with a hair-splitting insistence on exact weight breaks.

Likewise, there are specific rule AND engineering, vehicle dynamics and aerodynamic reasons that make the nosebleed stance just flat wrong.

EDIT: I don't have a problem with anybody building anything they want to. If someone wants a replica of a nose-up nostalgia car, fine...but don't present it as a period gasser when it's not.

Once somebody knows what's what, then it's a personal choice as to how they want to proceed.

Not the same at all as ignorance.

Edited October 9, 2018 by Ace-Garageguy

[Oldmopars]

19 minutes ago, smhardesty said:

Let me ask you something, Scott. Do you intend to enter this build in a contest/show somewhere where the rules state all details on the build must be correct or be disqualified? If not, why not relax a little and just get somewhere close on your class designation? There are a lot of unknowns in the scale world that wouldn't be on a 1:1 car. For instance and as stated previously, the car might be stripped of every once of weight legally possible, plus a few illegal pounds, OR as Muncie stated, the car might have had some weight added to push it into the next lower class, especially if it was close to the weight break but the motor was a bit weak for whatever reason.

As for finding "errors" in photos and drawings, there is too much unknown to be sure they are errors. The "Anatomy of a Gasser" is an artist's rendering for "Street Rodder" magazine. Maybe the artist just didn't know, or maybe it just slipped by him. And street rods don't necessarily depict an NHRA race car. 

Try this. Do an image search for "41 Willys gasser" in your search engine of choice. Then just browse through all the images noting the different class designations. Same car photo to photo, but you'll find lots of different classes.

Choose the year you want your car to depict, look at the rules for that year, locate the weight of your car on the 'Net, divide by the cubes, decide if your engine will be supercharged or not, then use the class designation from the table in the rulebook.

The short answer is NO, this will most likely just be a shelf model, just for me. But, if I am going to build something I know very little about, I research it and find out what I can. I do not like current drag racing, but after doing this research I have become very fond of the early 60's Gasser class. I learned that some big changes came in 1962, and this is cool to me. So, I want to build a car that is a good representation of a car from that era. I may never build another drag car, but I might.

3 minutes ago, Ace-Garageguy said:

What gets tiring to those of us who actually know is things like the obviously non-supercharged cars running a blown class reg, or the endless repetition that the nose-high attitude is correct (based apparently on mis-interpretation of photos of in-period cars launching, or relying on photos of the equally endless stream of "nostalgia" cars built recently with their noses a mile high while at rest.

There is no excuse for the former. Supercharged vs. non-supercharged is pretty obvious, and it's nothing to do with a hair-splitting insistence on exact weight breaks.

Likewise, there are specific rule AND engineering/vehicle dynamics reasons that make the nosebleed stance just flat wrong.

 

I know that having the nose way high in the air is wrong, but I have seen a lot of pictures of gassers at rest and the nose always seems to be higher than the rear. More like a 2-3 degree angle as apposed to the 10 degree angle I see a lot of. I am limited on how low I can get the front due to the axle hitting the oil pan. I do know that the centerline of the crank needs to be at 24in or less from the ground according to the 1962 rules. I know racers pushed this to get the weight transfer to the rear due to the hard rubber of the slicks of the day. I willraise the back just a little to keep the stance as close to the era as possible.

[Ace-Garageguy]

33 minutes ago, Oldmopars said:

...I know that having the nose way high in the air is wrong, but I have seen a lot of pictures of gassers at rest and the nose always seems to be higher than the rear. More like a 2-3 degree angle as apposed to the 10 degree angle I see a lot of.

I get your point, but just for grins, I did an image search for "gasser". The VAST majority of what comes up is recently built "nostalgia" cars, almost all the product, again, of misunderstanding.

I guarantee you...if you look at period photos, and photos of old cars that have been restored correctly to as-was condition, the overwhelming majority of THOSE will have level, close-to-level, or slightly nose-down attitudes. And the faster the trap speeds, the more likely the cars would be nose-down at rest.

   

And probably THE most famous gasser in the history of the known universe...the Stone Woods Cook Willys. Here's the original Olds engined car, sitting level at rest.

This car is launching...nose up. The suspension was specifically developed to allow it to do just that.  

There were some nose-high oddballs in the wayback too, but usually not running real fast under the major sanctioning bodies.  

^^^ I don't see any way this thing could pass the 24"-to-crank-centerline rule...though it apparently ran legally in its where and when.  

Edited October 9, 2018 by Ace-Garageguy

[Ace-Garageguy]

I'm sure a lot of you already know, but to see tons of photos that are representative of the gassers as they actually ran, check out George Klass Remembers:   http://georgeklass.net/gassers.html

And though there were a few cars that sat nose-high, some even silly nose-high, pay attention to the majority. Definitely pay attention to whether the cars are launching or at rest. Also pay attention to the exact time period. As the cars ran faster (not ET, but top-end speed) through the traps, the noses came down when the cars were sitting still. This is simply because, as the car settles on its suspension AFTER the initial brutal acceleration at launch, a car that starts nose-high will stay nose-high at speed.

Drive a car at 110-140 MPH with the nose in the air. The nose will just get lighter and lighter, and it will become entirely uncontrollable as the tires barely touch the ground. Push it, you can easily end up on your back, or in the next lane, or into the wall.

Edited October 9, 2018 by Ace-Garageguy

[Oldmopars]

34 minutes ago, Ace-Garageguy said:

I'm sure a lot of you already know, but to see tons of photos that are representative of the gassers as they actually ran, check out George Klass Remembers:   http://georgeklass.net/gassers.html

And though there were a few cars that sat nose-high, some even silly nose-high, pay attention to the majority. Definitely pay attention to whether the cars are launching or at rest. Also pay attention to the exact time period. As the cars ran faster (not ET, but top-end speed) through the traps, the noses came down when the cars were sitting still. This is simply because, as the car settles on its suspension AFTER the initial brutal acceleration at launch, a car that starts nose-high will stay nose-high at speed.

Drive a car at 110-140 MPH with the nose in the air. The nose will just get lighter and lighter, and it will become entirely uncontrollable as the tires barely touch the ground. Push it, you can easily end up on your back, or in the next lane, or into the wall.

Thanks, I did some tweaking and I now have the car sitting just slightly nose down. A little heat to the front springs helped adjust things ever so slightly. I also checked, and the crank centerline is right at or slightly less then 24in(scale)

I know that other than the pictures I post here, I am likely the only person that will ever see it. But, it is nice for me to know that what I built is a correct representation of the Gassers of the era.

Edited October 9, 2018 by Oldmopars

[smhardesty]

2 hours ago, Oldmopars said:

The short answer is NO, this will most likely just be a shelf model, just for me. But, if I am going to build something I know very little about, I research it and find out what I can. I do not like current drag racing, but after doing this research I have become very fond of the early 60's Gasser class. I learned that some big changes came in 1962, and this is cool to me. So, I want to build a car that is a good representation of a car from that era. I may never build another drag car, but I might.

I know that having the nose way high in the air is wrong, 

I do the same thing. I'd like my builds to be as close to realistic as I can make them. My real point was for you not to get TOO caught up in whether your build is a C/G or a D/G. You can drive yourself nuts trying to be that exact. Like Bill said, posting a non-supercharged class designation in the window of a car with a big, old blower and hat sticking through the hood is an obvious mistake you'd want to avoid.

As for nose to the sky stances being "wrong", well that's not entirely true. Exceptions to the norm - yes, but they can't be labeled as wrong. Once again, as Bill has already stated, you'll find photos of gassers from all periods that seem to somehow openly deny conforming to the 24" rule. There has to be something we're missing by only viewing the photos and not knowing all the facts about that car.

Build your car the way you think it should be. This is a hobby and should be fun. Don't turn it into a job or a school project that is to be "graded".

Edited October 9, 2018 by smhardesty