HODRA – HO Drag Racers Association

Gasser Classes as listed below were started in the 50′s. In 1958, a gas class racer was basically a hot street coupe. No engine setback was allowed, all gassers had to have working lights, wipers, starter, generator and all other street equipment. Fans and belts were optional, but radiators were required. The car also had to be currently licensed for the street. Full exhaust systems, including mufflers, were required but could be unhooked for competition, although they had to remain on the car.
What this provided for was a class for racers to run a “hopped-up” street machine. The cars were required to have full “factory-type” upholstery although two buckets could replace the standard bench seat as long as both were fully upholstered. Customs were allowed as long as the car wasn’t chopped, channeled or sectioned a total of more than four inches. Four stock fenders and a rear bumper were required. Full transmissions were also required. Quick-change rear-ends, locked differentials or ratchet-type rear-ends (high torque) were permissible with safety hubs. Four-wheel brakes were required as well.

There were only five gas classes that were classified according to total car weight divided by total engine displacement cubic inches. Designations were A/G, B/G, C/G, D/G or E/G preceded by car number. Use of a supercharger moved you up one class.
The designation breakdowns were as follows:
A/G – 0 to 8.99 pounds per cubic inch
B/G – 9.00 to 10.99 pounds per cubic inch
C/G – 11.00 to 12.99 pounds per cubic inch
D/G – 13.00 to 13.99 pounds per cubic inch
E/G – 14.00 or more pounds per cubic inch
1960 was the first year for supercharged gasser class symbols. By 1960, the rules had changed significantly. By then, engine setback of up to 10% was permitted although most of the street equipment rules were still in force. The reason that the setback rule was introduced is reasonably simple. There was nothing in the rules that required the original engine in the car to be used. When someone performed an engine swap in a Model A, for instance, chances were that they would have to cut the firewall for the engine to fit. The cars were still required to have full street equipment, including registration and plates. A maximum engine height of 24″ from the ground to the crankshaft centerline was established. Minimum wheelbase was increased from 86″ to 92″. Weight breaks were little changed with the following exception. For the 1961 season A/Gas and A/GS classes were changed to provide for a minimum weight of 4.00-lbs./cu. in. from the previous 0.00 minimums.
1962 saw some changes as NHRA rule changes for 1962 were evidence that drag racing had finally accepted the gas coupe/sedan competitors to be serious racers. The rules that required full street equipment including mufflers, wipers, horns, generators, emergency brakes, license plates and registration were now gone. Roll-up side windows were no longer required and could be replaced by Plexiglas windows screwed to the window frame. They were now real racecars. The other change, affecting only the A/GS class was the decision to raise the minimum weight to 5.00-lbs./cu. in. There were only a couple of rule changes for 1963. The first raised the minimum weight for A/GS cars to 6.00-lbs./cu. in. and the second allowed, even though they only had a 90.5″ wheelbase, 48-53 Anglias to compete in the unblown classes with small block engines.
In 1964, the basic rules for Gassers were unchanged from 1963. Many of the rules were changed in 1962 and the Gassers were now much less “dual-purpose” street & strip machines than had been required prior to 1962. The bodies were required to be a coupe or sedan body originally produced by an American automobile manufacturer, with the following exception “There are at present a few foreign coupe and sedan bodied cars that, in general characteristics, better meet the requirements of Gas Coupes/Sedans class better than sports car class. Provided these car bodies and cars do meet all other class requirements” wheelbase, etc. these cars are classed according to cubic-inch displacement to weight under this section”. As in 62 and 63, the Anglia was restricted to small-block, unblown engines only. Moderate customizing was permitted, but the total height of the body couldn’t be reduced more than 4″. Fiberglass fenders, hoods, doors, and trunk lids were allowed, but their use required the addition of a roll bar which was otherwise only required in the supercharged classes, A/G, and all convertibles or customized classes. Yes, convertibles were permitted in the Gasser classes, but had to run with the top up. The rules also required the seats to be in the stock location, but they were permitted to be relocated no more than 4″ rearward to allow additional legroom. The other interior rules were subject to a lot of interpretation. The rules for “Upholstery” read as follows: “Interiors may not be gutted. Must run full upholstery, equivalent to factory specifications. Floor mats optional. Bucket seats may replace stock seats (two required), only if they are fully upholstered. Rear seats are optional. Factory type upholstery and/or paneling must be used in lieu of the above.” So basically as interpreted, you could rip out the stock seats and carpeting, replace them with lightweight bucket seats and dump the rear seat.
The class breakdowns for this period were according to the following tables.

Supercharged classes:
A/GS-6.00 to 8.99 lbs. per cubic inch
B/GS-9.00 to 12.59 lbs. per cubic inch
C/GS-12.60 or more lbs. per cubic inch
Unsupercharged classes:
A/Gas-5.00 to 8.99 lbs. per cubic inch
B/Gas-9.00 to 10.49 lbs. per cubic inch
C/Gas-10.50 to 11.49 lbs. per cubic inch
D/Gas-11.50 to 12.99 lbs. per cubic inch
E/Gas-13.00 to 14.59 lbs. per cubic inch
F/Gas-14.60 or more lbs. per cubic inch
G/Gas-5.00 to 10.99 lbs. per cubic inch
H/Gas-11.00 or more lbs. per cubic inch
G/Gas and H/Gas were for non-supercharged pre-1960 flathead V-8’s, in-line six cylinder and straight eight engines with stock production-type heads and pre-1960 unblown 4-cylinders with any type head. For 1965, about the only noticeable change in the rules was the addition of a “Batteries” section which required all wet-cell batteries to be located outside the passenger and driver compartment. The rules also specified that a maximum of 2 passenger car batteries may be used and they couldn’t weigh more than 150 pounds combined.
1966 saw a redistribution of the unblown classes as shown in the following table:
A/Gas=5.00 to 6.99 lbs. per cubic inch
B/Gas=7.00 to 8.99 lbs. per cubic inch
C/Gas=9.00 to 10.99 lbs. per cubic inch
D/Gas=11.00 to 12.99 lbs. per cubic inch
E/Gas=13.00 to 14.59 lbs. per cubic inch
F/Gas=Unchanged from 1965
G/Gas=Unchanged from 1965
H/Gas=Unchanged from 1965
The other change for 1966 was some slight changes in the weight breaks for the supercharged cars, and a redefinition of the classes. Instead of being known as “A/Gas Supercharged”, for instance, it would now be known as “AA/Gas”. NHRA’s stated 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.
1966 Supercharged classes were symbolized as follows:
AA/G-6.00 to 8.99 lbs. per cubic inch
BB/G-9.00 to 11.99 lbs. per cubic inch
CC/G-12.00 or more lbs. per cubic inch

The rules for 1967 were unchanged for unblown gassers running A/Gas through F/Gas. The “flathead” classes G/Gas and H/Gas saw some major changes though. G/Gas, at 5.00 or more lbs. per cubic inch, was now for “Non-supercharged flathead V-8’s, in-line six-cylinder, opposed six-cylinder and straight-eight engines with any type head. H/Gas, 11.00 or more lbs. per cubic inch, was for the same engines but with stock production-type heads. Noticeably absent from the “Wheelbase” section of the rules in 1967 was the passage specifying “small-block” only power for the Anglia. The supercharger was still forbidden, however.

The blown gas classes were realigned somewhat as shown below.

AA/G-5.00 to 7.99 lbs. per cubic inch
BB/G-8.00 to 10.99 lbs. per cubic inch
CC/G-11.00 or more lbs. per cubic inch

1967 was also the year when the newer body styles began showing up in the Gasser classes. While many decry this as the “death of the Gassers”, keep in mind that the racers in the classes were there to WIN, not to keep things “nostalgic”. They merely took advantage of the existing rules as written in order to try and win races.

1968 saw some changes as follows. In the Supercharged Gas classes, the “S” was back! As far as other changes for the gas classes, there were some fairly big changes. The biggest was probably in the frame section of the rules. AA/GS through B/G and all cars with unibody construction would now be allowed to use rectangular or square steel tubing in frame construction. The minimum was .120 wall thickness and 2×3 inch rectangular or the equivalent square tubing. Prior to this, the rules called for a “stock automobile type frame”. The weight breaks for the blown cars were unchanged from the prior year, but a little bit of “Tightening up” took place in the upper ranks of the unblown classes and the major shakeup was in the G/Gas and lower classes.

The class designations for unsupercharged engines were as follows:

A/Gas=5.00 to 6.49 lbs. per cu. in. Was 5.00 to 6.99 lbs. per cu. in.
B/Gas-6.50 to 7.99 lbs. per cu. in. Was 7.00 to 8.99 lbs. per cu. in.
C/Gas-8.00 to 9.49 lbs. per cu. in. Was 9.00 to 10.99 lbs. per cu. in.
D/Gas-9.50 to 10.99 lbs. per cu. in. Was 11.00 to 12.99 lbs. per cu. in.
E/Gas-11.00 to 12.49 lbs. per cu. in. Was 13.00 to 14.59 lbs. per cu. in.
F/Gas-12.50 to 13.99 lbs. per cu. in. Was 14.60 lbs. per cu. in. or more
G/Gas-14.0 lbs. per cu. in. or more. Was flathead class
H/Gas-6.00 to 8.99 lbs. per cu. in.
I/Gas-9.00 to 11.99 lbs. per cu. in.
J/Gas-12.00 lbs. per cu. in. or more.
K/Gas-10.00 lbs. per cu. in. or more.

A bit of explanation is probably in order regarding the H/Gas through K/Gas classes. The H, I, and J classes were for “Non-supercharged flathead V-8s, in-line and opposed six-cylinder, straight-eights, and in-line and opposed four-cylinder engines with any type heads.” K/Gas was for “Non-supercharged flathead V-8s, in-line fours or sixes and straight-eight engines of American manufacture with stock production type heads installed in American production bodies.” Basically what was happening was that NHRA was making a place for the VWs and Fiats that were starting to appear in great numbers in the lower gas classes.

In 1969, while AA/GS remained unchanged, BB/GS tightened up from requiring 8.00 to 10.99 lbs./cu. in. to 8.00 to 9.99 lbs/cu. in. and anything at 10.00 or more lbs/cu. in. was now in CC/GS. A/Gas through E/Gas were also unchanged, but F/Gas was now 12.50 or more lbs./cu. in. Another reshuffling took place below that, as G/Gas was back to a flathead class and K/Gas was dropped.

The breakdown is as follows:

G/Gas-6.00 to 7.99 lbs. per cu. in. Was H/Gas
H/Gas-8.00 to 10.99 lbs. per cu. in. Was I/Gas
I/Gas-11.00 lbs. per cu. in. or more. Was J/Gas
J/Gas-10.00 lbs. per cu. in. or more. Was K/Gas
K/Gas was Dropped

Other than that, the big news was that blown Anglias were now legal in NHRA. Prior to 1969, Anglias, with their 90 inch wheelbase, were only legal for the unblown gasser classes. As of 1969, NHRA lowered the minimum wheelbase from 92 inches to 90 inches.