Tri-Power ’61 Pontiac Bubble Top Important Step in Muscle Car Evolution

The ’61 Bubble Top Laid The Foundations For The Muscle Car As We Know It

Updated September 27, 2018

There’s no consensus as to the which was the true first muscle car, however we can trace its evolution. Manufacturers had been upping horsepower since the mid-1950s, so the exact moment or model is hard to define (though lots of folks point to the 1964 GTO).

The ’61 Pontiac Ventura Tri-Power is an important stop along that route, given that while the car shrank around it, engine size remained the same, and that Pontiac was willing to ship you go-faster parts in the trunk of your new car, as long as you checked the right boxes on the order form.

 '61 Bubble Top 1

The Ventura was introduced for the 1960 model year as a higher priced model on Pontiac’s full-size chassis, shared with the Catalina. It was available as a four-door sedan and two-door hardtop. For 1961 Pontiac shrank the Ventura, shaving  200 pounds  and cutting the wheelbase by three inches, which made it one of the lightest full-size models. Good news for NHRA Super Stock racers.

’61 Pontiac Bubble Top

 '61 Bubble Top 2

The downsizing also created one of the most attractive and desirable mid-century automotive designs, referred to as the “bubbletop.” This was a one-year-only body style for Buick, Oldsmobile and Pontiac, with a second year on the Chevrolet Bel Air line only.

 '61 Bubble Top 3

The top-of-the-line setups for the 389 Pontiac V-8 in 1961 were the 333 HP single four-barrel engine and the Tri-Power (three one barrel carbs), rated at 348 horsepower.The Ventura could be ordered with either a Borg Warner four-speed manual or an automatic transmission.

The savvy buyer (racer) could order Super Duty parts along with the car, parts like an engine  block with 4-bolt main caps and stiffening ribs in the bottom end, forged steel crankshaft, forged connecting rods, and 10.75:1 pistons. Updated cylinder heads were also available as well as a hotter camshaft, an aluminum  intake and cast-iron headers (good thing they came with big trunks). Not fitting in the trunk were further options like aluminum bumpers, fenders, and hood.

So through most of 1961 it was up to the racer or a cooperative Pontiac dealer to install the Super Duty parts, however, there were a about a dozen cars built in the fall of ’61 with a 421 CID engine option.

 '61 Bubble Top 4

Motor Trend tested the Tri-Power Ventura and reported 0-60 MPH at 8.2 seconds, with a 1/4 mile E.T. of 15.5 at 93 MPH. The value of the Super Duty parts is evidenced below.

A four speed 389 V-8 Ventura prepped by Royal Pontiac dealership in Royal Oak, Michigan and driven by Jim Wangers won the 1961 NHRA Super Stock championship with a low E.T. of 14.1 at 100 mph (1.4 seconds faster than stock).





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Chris Riley
About Chris Riley

I have been wrecking cars for as long as I've been driving them but I keep coming back for more. Two wheels or four, I'm all in. gives me a chance to give something back to the automobile community.

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