1965 marked the very first year that the big-block 396 engine was released to the public. The elusive 1965 Chevelle Z-16 had one of these new big-blocks sitting between the frame rails, which then spurred the 1966 Chevelle SS 396. These engines were also fitted into Corvettes and later on into Novas, Camaros, and Impalas. They were refined and bumped up in power to the peak of the horsepower wars in 1970 with the LS6 454. The big-block set the stage for the horsepower wars and forever changed the history of Chevrolet.
Before the mighty LS6 became King of the Hill, you can trace the big-block ancestry to the Mark I big-block 409 engine that adorned early 1960s Impalas. This 409 big-block never gained the popularity of the later models, but that’s where it all started. Taking a step back into time, we caught up with Bill Howell, now of Howell EFI who worked on some of the very first big-block Chevrolet motors.
While at General Motors he worked on the 409 first big-blocks along with the Mark IV big-block that we all know and love. He started his journey in the summer of 1961 and worked on the engine development side until September 1987. From there he started up Howell EFI, which specializes in wiring up electronic fuel injection motors. Even though he’s now a young 81 years old, he remembers 1961 like it was yesterday.
CHC: Is there any neat information the public doesn’t really know about big-blocks?
Howell: “Well, I’ll tell you what we struggled with a little with the big block, especially in the performance Corvettes. Getting the oil flow to where we can live with a wet sump oil pan and a four-quart pan. We had in a mechanical lifter with very high oil flow because of the lifter design. The problem with that was the lifter was designed by the Chief Engineer at that time. In his earlier days he wouldn’t talk about changing the design. The lifter leaked oil inside the engine like crazy, and it created a lot of oil flow. If you can’t get the oil back to the oil pan quick enough, it eventually runs out of oil pressure. So we struggled probably more than anything with that. Oil flow took quite a while to really get under control. Also during that time period they went from five-quart to four-quart oil pan, which was a big problem.”
“The reason for the four-quart pan was to get the engines lower in the cars. In the Corvette it had to be fairly close to the ground, closer than a passenger car. The trucks I don’t think were any problem but if you put a big-block in a Camaro or something, it’s bound to end up with the oil pan closer to the ground.”
CHC: The oil problems the big-block had was contributed to the Chief Engineers lifters that he wouldn’t change?
Howell: “[laughs] I would say yes, but also we didn’t do any serious development on minimum oil flows and trying to control the oil flows. That was one of the things in the racing end and with the rest of my career I always wanted to do-design an engine development program that would really science out the actual requirement for how many gallons per minute does it take. The more you cut that down the easier it is to make a system control.”
CHC: These faulty lifters, are they the ones that we know today?
Howell: “They’re called Fiddle Valve Lifters I think. I’m assuming that they used them right up to the end of the flat tappet mechanical lifters. Hydraulic lifters didn’t have the same problem.”
CHC: Why did the 409 die out?
Howell: “The 409 was not a very successful NASCAR racing engine as it was originally designed as a truck engine. Even though the corporation had forbidden our participation in automobile racing at the time, Pontiac was doing it out the backdoor. I don’t think that there was any Buick or Oldsmobile performance going out. Chevrolet didn’t want to get left behind. Plus we had engineers and people in charge of the design that felt that performance was something we oughta keep abreast of. They decided around 1960 or ’61 to design a brand new engine to incorporate everything that they thought they knew and it would be better than a 409. They developed that and started running it in 1962 and it was called a Mark II.”
CHC: What’s the story of the Mark I, II, IV naming and why wasn’t there a Mark III?
Howell: “The Mark IV, the reason they called it the Mark IV is because we had three variations before then. The Mark I was the 409, the Mark II was the engine that we designed in ’61, ’62, and there never was a Mark III. At the time that Studebaker Packard went out of business they had a big V8. GM was contemplating buying that tooling from Packard and using it to make a V8 for General Motors. That was going to be the Mark III, which never happened. We went from the Mark II to the Mark IV’s, so we stayed with the Mark IV ever since, once that was considered a final design. The Mark IV is the big-block we all know now.”
CHC: What are your thoughts on the big-block?
Howell: “It’s been an engine with a lot of potential over the years. Drag racers have done a lot of good with it and some of the boat racers. What’s impressed me at the time I retired in ’87, they still hadn’t developed port flow to the extent that they did later. We had one of the early air flow boxes. The airflow box stuff was just coming on steam and really making some difference in the production engines about ’87 when I retired.”
“One of the things that I was privileged to help or to test the first samples of was the Optron where you could actually watch the motion of a valve at high speed. If you could image camshaft design and valve spring design and all those components were very difficult at high engine speeds because the only tool you had to look at what was going on was a strobe light. You could take a strobe light and you could at a valvetrain and you could see the valve springs surging and you could see the valve bounce but you couldn’t really develop a better system. The Optron came along about 1963, maybe ’64.”
CHC: Can you explain what an Optron is?
Howell: “What an Optron does is reflect the light off of a polished edge like on a valve spring cap or you can even do it if you cut away the head. You don’t have to have a running engine to cut away the head and you can actually watch the edge of valve. But it transfers that motion onto an oscilloscope. With this you can watch the electronic trace on an oscilloscope and you can watch the valve profile. It should follow the camshaft profile up and down but as soon as you get up to higher speeds it quits following the camshaft perfectly and it starts bouncing when it seats or lifting off the lobe when it goes over the nose of the camshaft. I ran the very first Optron that ever came to Chevrolet engineering back in the early 60’s and the room had to be absolutely dark, the thing was set up on a surveyors tripod and if you bumped it, you lost a half a day’s work trying to get it back lined up. We made the set up a lot better as years went by.”
“As an example, when I went to work for Chevy in ’61, the 409 would put out 425 horsepower. When we put the Z/28 on the market in 1967, the Z/28 engine with a racing cam would put out 425 horsepower at 6400 RPM. We made that much progress over the years in camshaft design and airflow. That’s a 100 cubic inches less. Obviously the torque wasn’t the same, but the horsepower was the same.”
“All the NASCAR teams eventually bought an optron during the 90’s maybe 2000s. They do their own valve train evaluations, durability tests, and everything. They may have something that’s beyond the optron now, I don’t know what it is because I kinda lost track of it. But that was a magical instrument in those days.”
CHC: You started with General Motors as a test engineer?
Howell: “What they do in the test lab is they’ll bring a new engineer in and give him work clothes. Then they will put him running the engines and taking them apart, putting them together, swapping the parts and running the tests themselves under the direction of another engineer or somebody with experience. Then when they get familiar enough with the product they will promote them to an actual engineer status and in my case it took about a year to get promoted to a real test engineer status. They want test engineers to write up the instructions for the operators as to what to test. You don’t test anything without a written order because they don’t want people going off on their own inventing, discovering, or blowing things up. And a lot of that stuff gets blown up, believe me! Or it used to.[laughs]”
CHC: After starting as a test engineer, where did you end up in your career?
Howell: “I was a test engineer up until the summer of 1967 and that was exclusively in the laboratory there at Chevrolet Engineering. Then they promoted me to another level and I went to work for Vince Piggins, father of the Z/28. Vince ran the performance group that they gradually built up, once the corporation decided that maybe racing wasn’t all bad and that it wasn’t going to cost them all their profits. The other parts of the automotive racing world there was Ford and Chrysler basically, and there wasn’t any Japanese then. One of the things that you have need to realize is that when all the corporations got out of racing in 1957, most of them quit making their heavy duty parts. Ford quit making them and Pontiac went to cast iron crankshafts and got rid of most of their good stuff. But Chevrolet decided they wanted to keep their good parts in the parts catalog so you can buy them from a dealer.”
“As time progressed and GM didn’t participate in NASCAR, they still worked on their heavy duty parts program and tried to keep good stuff in the parts catalog that you could buy form a Chevrolet dealer. So in essence that’s what made every Saturday night racer a Chevrolet racer, because he could buy the parts. You couldn’t buy Ford parts and you couldn’t buy good Chrysler parts. Only thing you could buy that would do a Saturday night racing with was Chevrolet parts. In that time period when none of the manufacturers were really participating in anything other than maybe NASCAR, we were building a racing base with the Saturday night racers and they were racing Chevrolets. They were towing them back and forth to the race track with a Chevrolet trucks too.”
CHC: Tell us about your history with Chevrolet and the big-block engine.
Howell: “I went to work at Chevy in the summer of 1961 and at that time our NASCAR racing engine was the 409. Even though we were not actively participating in NASCAR, our engine group chose to try and keep abreast of what was going on and we had a little bit of backdoor help going out to people like Rex White. There might have been another team or two but pretty much it was a closed shop.” “The 409 at that time was running a Carter AFB, the biggest carburetor that Carter made in a four barrel. It made about 425 horsepower on a dyno and at that time we corrected everything to a 60 degree correction factor that was called a SAE Gross Power Correction. All the numbers from that era were numbers that would be lower if you use today’s correction factors on them. We kept that 60 degree SAE correction clear up in to about 1970 something before we went away from it as a corporation.”
CHC: What are the differences between the Mark I, Mark II and Mark IV big-blocks?
Howell: “For the Mark I, the 409 was a design where the cylinder block deck was not perpendicular to the bore. The cylinder block was machined on a slant to the bore and the head was a just a flat piece of metal with a couple valves in it, to make it simple. It wasn’t a bad truck engine, but it was a design that engineering staff came up with and it was a flop.”
“The Mark II, we had some initial 409 displacement ones running then we brought that up to 427 which was the NASCAR legal limit at the time. The basic difference in it was that the decks were perpendicular to the bores, the cylinder heads had the valves arranged like the Mark IV where they came in at an angle where you have two angles instead of just straight in and down into the bore. I’m sure you’re familiar with the difference in the Mark IV head from a small-block. That was the evolution of that was the Mark II and the Mark II’s originally had the same crankshaft, main bearing diameters and rod bearing diameters that the 409 had. That’s basically the main difference. Plus you couldn’t swap heads side to side, they were designed with a right hand head and a left hand head. We kept developing that engine right up into ’64 and then we started the development of the Mark IV.”
“What they did with the Mark IV was retaining the different valve angles, made the cylinder head so they can swap from side to side and increase the main bearing and the rod journal diameters to pick up the strength in the crankshaft. They went to a four-bolt main bearing because the mains were walking around on the block and they were only two bolt on the Mark I and the Mark II.”
Howell: “I hate to say that it was trial and error, but it’s almost all trial and error. You put the best designers you have on a task or at least you try to. They’ve got the knowledge that they developed over years and they draw parts up or have them drawn up on the drawing board to their satisfaction. Then they build a prototype part like that and it goes to the test lab along with the engine or the engine itself goes. You would then have GM standard series of tests that they run on depending on what they’re testing.”
“They had a book that gave the standard GM test for all that stuff. If it met those standards or even if it didn’t, you fed that information back to the design engineer or the responsible engineer and he said ‘okay well lets change this and that,’ and do another prototype. That’s pretty much the way engines were done and honestly that’s the way they’re done today in the world. There’s no magic to it. It’s all based on past design experience and development. My career was in development.”
CHC: The Mark II that was developed never made it into production or into any cars?
Howell: “No, it never went into production. In the 1963 racing season there was probably 15 of them out runing in NASCAR over the summer. As people wore them out they couldn’t get replacement parts. Junior Johnson managed the whole year in ’63 and won the championship with a Mark II. But that’s pretty much the end of it until GM got back into NASCAR around 1972.”
CHC: What was the cubic inches on the Mark II engine?
Howell: “Well it started as a 409 then we swelled it up to 427. Then in ’63 because we heard that NASCAR was going to 396 to cut the engine size down, we started making it as a 396. The first 396 development engines I had were Mark II’s and then we started switched over and started doing the prototype Mark IV’s, which were also 396 cubic inches. The first production Mark IV’s in 1965 were all 396 cubic inches.”
CHC: The 396 as we know it became about because of a NASCAR regulation?
Howell: “Most people wouldn’t realize it, but a NASCAR rumor made us change displacements.[laughs]”
CHC: What changed the policy of Chevy to give the green light to bring the big-block into the mainstream?
Howell: “If you can put a motor into a production car there was no problem with it. Of course, performance cars were starting to take off in the middle 60’s and we had naturally good performance engines sitting on the shelf because we had been doing this development. We start sticking them in Chevelles, Corvettes and whatever else as soon as we could. The corporation didn’t actually get into what you called professional racing until the Trans Am came along and we had to promote the Camaro against the Mustang. That was all done as small block, though.”
CHC: What was the mentality of Chevrolet back in the 1960’s?
Howell: “The general public, the news media, and even the hot rod magazines were not aware of what we were doing behind the closed doors at engineering. The Chaparral program for instance, was completely secret and our connections with Jim Hall. I think maybe that started about ’65, I’m not sure. Jim Hall did a run of lightweight Corvettes I think around ’63 with all aluminum V8s in them and stuff like that. That was not real general knowledge in the industry.”
CHC: Did Chevrolet do a lot of things behind closed doors?
Howell: “Well experimenting yes, but I guess I don’t know how they justified the Chaparral program for instance. They did run it with an automatic transmission I know that. That might have been some value. I think maybe they got some aerodynamic benefit from it and they also developed some technical measuring and transmitting it by radio so you had real time data coming off the test car that you could analyze immediately and that was new at that time.”
CHC: What was it like to work for GM back then? Was it stressful? Exciting?
Howell: “I would say it was very exciting, it certainly was exciting for me. I think most of the dynamometer operation stuff was very interesting to the people that were involved in it. The Chaparral stuff was done in what we called R&D and they were behind locked doors, but they had to run their stuff on the same dynamometer as we did. So we were a little bit aware of what they were doing. And they were messing with Weber carburetors and dry sump systems and things like that. It was an exciting time.”
CHC: How quickly did development happen back then?
Howell: “I think at that time we were probably running two shifts in the machine shop and some people were running six days a week. Before the advent of computer-aided drafting, it just took time to do stuff.”
CHC: What did you do after you retired?
Howell: “After I retired in ’87 I was still too young to sit around and do nothing. What GM did was had a reduction of force in ’87, so they were looking to eliminate jobs and they were offering early retirement to people and that’s what I took. But I knew that fuel injection was a coming thing. At that time only the Corvette had port fuel injection, with eight injectors. There were people wanting to put Corvette engines into other cars. So I thought well I’ll learn how to build wiring harnesses and maybe that’ll be the coming thing. It turned out it was a good idea.[laughs]”
We would like to thank Bill Howell for taking time out of his day and giving us a sneak peak back into the history of Chevrolet. Next time you see a big-block, you will know just a little bit more about them than the person standing next to you.