The following is from the upcoming book Bonneville and the Southern California Timing Association, a complilation of records and achievments, 1949 -2009, (working title).
This is wordy so don't read if it turns out to be boring, in rich text format.
DW
GT Class – rules and records
1966
Series production sports cars as accepted for road racing in the “Production” category, (did this mean SCCA competition?) as well as limited production cars by a recognized manufacturer which are primarily intended for comfortable high speed touring. No engine swaps permitted, nor are alterations to height, width, or contour of body. MINOR customizing is permitted. Stock windshield may not be removed or lowered. Any covering on an open cockpit must be of non-rigid material and blowers are allowed as stated above.
Engine break F - 97.7 to 164.7 cid
Blown engines limited to 5200 cc, 317.2 cid - class C, and advance two classes. If a blown engine was to used in F/GT it had to be class H - 0 to 76.2 cid.
Record – not available
1967-1968 not available
1969
Rules for GT class are the same as 1966-1968 (we think) and add the following:
This category is subject to the same rules in regard to modifications and equipment as in Gas Production Coupe and Sedan except that minor customizing is permitted and blowers are allowed as stated above. Must be 500 produced yearly.
Note – The rules for Gas Production Coupe and Sedan are much the same as those in effect today in the Production Category.
F - 97.7 cid to 164,7 cid., if blown H – 0 to 76.2 cid.
Record – F/GT William S Gurnee W. Gurnee ’66 137.311
1972
The GT rules remain as before with the addition of:
Engine swaps permitted as long as they are of the same manufacturer, i.e. Ford into Ford, Porsche into Porsche, etc.
Rules for this category will be strictly enforced to insure as far as possible that cars entered are typical of originally produced automobile as sold to the public from dealers.
Engine size and record remain the same.
1973
Rules remain and engine break remain the same as in 1972.
Record – F/GT Racer’s Z-Z-Z-Z-Z-Z R. Brown ’72 152.134
1974
The GT rules remain the same as previous years.
Engine size changed to 0 – 183 cid.
Record remains at 152.134
1975
The rules remain as before with the following changes:
The word Gas is dropped from the previous Gas Production Coupe and Sedan. Each class heading is now titled with either Gas or Fuel.
In this class, independent rear suspensions may be replaced with any non quick change rear end.
Engine size has been changed again; F – 98 to 164 cid.
Record is still 152.134
1976
Rules for the GT class are the same as 1975.
Engine size changed to; F – 123 to 183 cid.
Record – F/GT Don Ricardo D. Ricardo ’67 153.711
I have no idea as to why the record reverted to 1967 with a faster speed, a typo maybe?
1977
The GT rules are still unchanged. The difference between the class in 1976 and 1977 is that the complete rule set from Production Coupe and Sedan class is now copied into the GT class write up. (starting a long standing policy of increasing the number of rule book pages)
Engine size remains: F – 123 to 183 cid
Record – F/GT Morgan-Wagner Jag G. Morgan ’76 135.95
Real confusion here. Why has a much slower speed been recorded as the new class speed set the year before? Research shows that it appears the Morgan-Wagner record was an El Mirage speed inadvertenly placed in the Bonneville record section. Notice that records are now listed to two decimal points rather than the three places as in previous years.
1978
Rules for GT class and engine class break remain unchanged.
Record – F/GT Nissan Motor Corp. R. Stockman ’76 166.037
Note that the record, set in 1976, has now been added to the rule book, erasing the error from the previous year. The record speeds now show three decimal places again.
1979
The rules have only one addition from the 1978 rule set:
This category does not include cars with rear seats suitable for continued adult occupancy.
Engine class and record are unchanged.
1980-1985
Rules and engine break remain unchanged.
Record – F/GT Robert R. Norwood R. Norwood ’85 168.721
1986-1988
No changes to rules, engine break or record.
1989
The GT class adds one important rule:
This class may run Nitrous Oxide, but advances two engine classes.
The engine break and record remain the same.
1990-1991
The rules, engine break and record are unchanged.
1991
The GT class rules and record remain unchanged.
A major modification to the classes is done by dropping the two class jump for using a blown engine of equivilant displacement. All engine classes will now have separate records for blown and unblown.
1992-2001
The GT rules, engine break and record remain the same.
2002
The GT class rules dropped the option of using Nitrous Oxide and incurring a two class penalty.
The engine break and record remain unchanged.
2003
The GT class rules, engine break and record remain unchanged.
2004
The GT class rules and engine break are unchanged.
The Bonneville records are now listed by month and year. This is to reflect at which event a record was set. August, 08 = Speedweek, September, 09 = World of Speed, October, 10 = World Finals.
F/GT – F Robert R. Norwood R. Norwood 08/85 168.721
2005-2007
The class rules and record are not changed.
The engine break is modified to accurately reflect the cc displacement equivilant:
F - 123.00 to 183.99 cid 2.016 to 3.014 liter
2008
The GT class rules in paragraph one are rewritten:
Series production sports cars and coupes like the Corvette, Honda S2000, Porsche 928 and Datsun Z 2+2, as well as limited production cars by a recognized manufacturer, which are primarily intended for comfortable high speed touring are considered to be GT cars. A production rate of at least 500 vehicles of the same model for sale to the general public is considered to meet the requirement of a production automobile. GT cars with four seats shall have committee approval to run in this class.
Also added :
Decals are not acceptable as meeting the headlight and taillight requirements
All vehicles shall use a seat designed for racing, see Section 3.D.1
The engine break and record are unchanged.
2009
The addition of floor pan is added to the list of required O.E.M. items for the class.
Engine break and record are the same.
2010
GT class rules and engine break remain unchanged.
Record is broken:
F Victory Motorsports B. Brown 09/10 172.974
