General Motors bowed to the performance tide in 1965, authorizing engines up to 400 cid in its intermediate cars.

Buick seized the change as a chance to put some spark in the Skylark.


The division's big-block V-8 actually displaced 401 cubic inches. Undeterred, Buick simply renamed it the "400", slipped it into its mid-size model, and created the Gran Sport. Teamed with a heavy-duty radiator and dual-exhausts, the 401 carried the same 325-bhp rating as in Buick's full-size models. ("Wildcat 445" on the air cleaner referred to the engine's torque rating.) To Buick's credit, the operation was more than just an engine transplant. Any Gran Sport--hardtop, pillared coupe, or convertible--got the convertible's beefed-up frame for better rigidity, plus specially valved shocks and heavy-duty springs. Up front went a thick anti-roll bar. The rear suspension got added links to fight axle windup and differential twist. Braking was improved with enlarged front wheel cylinders.

With the standard three-speed manual, the Gran Sport package added $253 to the cost of a regular Skylark. It jumped to $420 with the four-speed manual, and $457 with Buick's two-speed Super Turbine 300 automatic. Top available ratio was 3.73:1. All Gran Sports had to be ordered with bucket seats this year, a $72 "mandatory option." Positraction should have been mandatory, too. As with other high powered intermediates, wheel spin off the line was a problem. But buyers were happy. This was a solid car with a smooth, responsive engine, good ride quality, and competent handling. Motor Trend remarked that its 12.3 mpg in city driving was "not bad at all." Buick sold nearly 70,000 Skylarks and Gran Sports this first year, and no one seemed to mind that it was not an all-out muscle car.

In '65 Buick introduced the Skylark Gran Sport in January of '65 and was a mid year production car. Because of this, it does not have a serial number designation.

*Editor note - There has been a lot of confusion in this area so I'll explain further. The Skylark and GS shared the same designation number. It was not until 1966 that the GS gained it's very own designation on the VIN plate to set itself apart from the normal Skylark line.

There are a good number of differences from a Skylark to a GS. Of these is a GS had a heavier suspension. Most easy to notice is the front sway bar is larger diameter than it's little brothers, the Skylark.

As for the engine, the GS had a special code.It is stamped into the block. Location is at the front top edge of the block directly behind the thermostat housing and before the valley pan. For '65 it will read "LR" followed by the serial number. The "L" is 1965 model year. The "R" is the speciffic code for the correct "GS" engine.

We've also seen in some rare instances where "LT" codes have also been used. We have several documented cases of this in the GS registry. If you are in doubt, double check the serial number to that of the block number and if they match you've probably got a winner. No 65 GS models came with small blocks, therefore all 65 GS were equipped with big block 401 motors.

Codes for other models of 401's is "LS" as used in Riviera, Wildcat and Electra. There is also the "LT" code 425 with two four barrel setup. Used in the Wildcat, Electra and the Riviera GS.

All '65 GS's had bucket seats. No ifs, ands, or buts about it . The "GS" A9 option came with the bucket seats only and there was an upcharge cost. Located on the firewall is the cowl tag. On the other side of that is the "TR" trim code. 154 is for white bucket seats, 157 is for red bucket seats, 158 is for black bucket seats and 159 is for saddle color buckets.

Some of the other differences between a Skylark and a GS are:

  • GS had a different frame. All GS models [body styles] had a fully boxed frame with a heavier rear cross member.

  • All GS had a special rear end. The gear set was a specially treated metal and the outer axle bearings were of greater diameter.

  • The front sway bar is larger diameter.

  • The coil springs are a heavier rate.

  • The front wheel cylinders are 1 1/8” vs 1 1/16 on the Skylarks and Specials.

  • The engine mounts and cast iron adapter plates are '65 and '66 GS only.

  • The exhaust is 2 1/4 " and the exhaust manifolds are GS only (they are cast iron).

  • Automatics ALL had a center console with floor shift. There were never any column shift '65 GS's.

  • All '65 &'66 GS's had a deluxe steering wheel. This is also used in a '65 Skylark and optional in a Special with deluxe trim.

  • The battery tray should be on the drivers side because the starter on the motor is on that side. The small block & six cylinder cars have the opposite setup.

  • The fenders should have the GS porthole emblems (portivents) "Yes there is a difference between the Special and Skylark fender emblems!".

  • Look on the backside of the fenders if possible and check if the rectangles look factory cut as the emblems set inside the fenders as normal Skylark emblems are simple bolted on with studs.

  • There should be no side moldings nor evidence of holes or clips that held on the moldings down the doors and quarters. Many times aftermarket side trim was added, but from the factory, the GS only had port hole emblems, name plates and rocker moldings (sometimes also optional wheel moldings).

** Note that all of the options above are simply reference points to how the 1965 GS came from the factory based upon the information we have from factory documentation. Other variations or options might exist and we'd like to learn about them. Many GS's have been repaired over the years with parts that may or may not be GS specific. Always do your research and base your decision upon the net of your results.

Regular Equipment for 1965

  • Heater and Defroster*

  • Re-usable Air Cleaner Element

  • Electric Windshield Wipers

  • Directional Signals

  • Dual Sun Shades

  • Custom Padded Seats

  • Ash Tray Front and Rear

  • Cigar Lighter

  • Instrument Panel Courtesy Light

  • Instrument Panel Safety Padding

  • Paddle-type Arm Rests

  • Rear Passenger Compartment Courtesy Lights (Convertible Only)

  • Ash Tray and Glove Compartment Lights

  • Carpet - Floor, Door and Cowl Area

  • Dual-Key Locking System

  • Plunger Type Door Locks

  • StepOn Parking Brake

  • Front Seat Belts*

  • 3 - Speed Synchromesh Transmission

  • DeLuxe Steering Wheel

  • Magic-Mirror Finish

  • Bright Exterior Mouldings

  • Skylark Wheel Covers

  • Dual Horns

  • 6,000 Mile Lubed Front Suspension

  • Self-adjusting Brakes

  • Delcotron Generator

  • 14-inch Wheels

  • Power - Operated Top

  • Full Flow Oil Filter

* A delete option at reduced cost

1965 Buick Skylark Gran Sport
Wheelbase, in. 115.0
Weight, lbs. 3720
Production 15,780
Price (Approx) $3800
Displacement 401 cid
Compression ratio 10.25:1
Horsepower @ rpm 325 @ 4400
Torque @ rpm 445 @ 2800
Performance, 0-60 mph: 7.8 sec
1/4 mile, sec @ mph 16.6 @ 86

production table