Pontiac fans of all sorts were very enthusiastic about our "Poncho Power" story that appeared in the July 2013 issue. We followed along as John Beck at Vintage Hot Rod/Pro Machine (vhrcustoms.com) built a 389 Pontiac for a 1932 Ford pickup owned by Paul Willis and it prompted an amazing number of emails. To illustrate the variety we offer the following:
Pontiac’s Super Duty engine program was legendary; it certainly made NHRA and NASCAR fans
Q For the last year I've been collecting parts to build a 1960s-style Gasser out of a 1952 Pontiac coupe. All my friends call it a boat, so it has been affectionately named the "Battleship". For an engine I was planning on running a big-block Chevy, I built motor mounts, had the dummy block in place, and was about to start building an engine. Then I saw the July issue of STREET RODDER and I changed my plans. I've torn out everything that had been done and I'm starting over.
What I've decided to do is replace the Chevy engine and build a replica of a 1962 421 Super Duty— I want the car to look like someone went to a Pontiac agency and came home with a new engine. I love the looks of the two-fours; in fact, I even plan on running the stock sheetmetal valve covers.
Via the Internet
A: The 421 Super Duty was a dealer-installed option in 1961, so back then what you are proposing could have been done. In 1962 the 421 SD became a factory option and while the factory rated these engines at 405 hp, Pontiac was being conservative—450 was a realistic number and some claim that the true numbers were more like 465 hp with over 500 lb-ft of torque. Unfortunately, it all came to an end in 1963 and less than 90 Super Duty Pontiacs were produced.
The standard 421 continued in production, then in 1967 the bore was increased to 4.120 inches, which bumped the cubic-inch count to a touch under 427 ci. In an obvious case of one-upmanship, Pontiac called it a 428 to distinguish it from Chevy's 427. In 1970 Pontiac increased the bore and stroke once again to create the 455, which was produced from 1970 through 1976. Any of these engines would be great in your Gasser.
A Boat of Another Sort
Russ Young’s 389 Pontiac wears a factory 3x2 manifold and carbs and a very cool set of Wei
Great Poncho 389 piece—loved the history. We both lived and rodded before the corporate engine. John built me a 389 for my flat-bottom V-drive boat. Brand name is Spico, built and delivered in Bakersfield in 1961. I'm the second owner. It's a heavy boat; plywood, fiberglass covered, inside and out.
The motor came with the boat and is obviously an early motor. When John took it apart he found a junkyard refurb. It had cylinder wall problems and two forged pistons. I wanted and got a low-end motor, idles slow and smooth in the no-wake zone and gets on top of the water quickly. The motor is stock, except for the cam—it has the original ignition, manifold, and carbs. Yes, it has three-twos but does not have roller lifters like Paul's. Of course, it's balanced and I coughed up for the dyno room. That's a no brainer. You get a broken-in motor that's tuned and ready to go, plus it's a hoot. Second best $500 I ever spent.
At 3,500 rpm the motors are identical. Mine, motor A, is at 415 lb-ft of torque and Paul's, motor B, is at 414.9. That's also the crossover point. Below that, motor A is better, and above that motor B is. The peak torque for each is best at 3,300 rpm, 417 lb-ft for A and 416 for B. At 2,500, A is at 402.8 and B is at 369.1. At 4,500 rpm, A makes 369.1 lb-ft and B is at 392.
There were three pulls, the first one on the middle carb only. The motor was lean and had a peak torque of 365 lb-ft. John then set the slider so all three carbs were open at full throttle. The motor went leaner with a peak torque of 334.4! John took a stab at going from 0.066 inch to 0.071 for the outside carbs for the final pull. The motor was still slightly lean at the top end and John said he could get a little more out of the motor by continuing to tweak the jets, but for my purposes the motor was good so I took it home and put it in my boat.
I'll have John do the same thing for my street motor.
Via the Internet