Automotively speaking–as well as in many other arenas–I’m a “Jack of all trades, master of none” sort of guy. After about the fifth or sixth Chevy engine L-code variation, I start to get a bit glassy-eyed. But I’m always eager to fill in the details, especially when they correct one of my mistakes. As usual, it was a commenter (Terry Boyce) who pointed out that I had made a commonly repeated mistake about the the 1965 Chevy 396 engines the other day. Time to set the record straight, and we’ll use the legendary 1965 Chevelle SS396 Z16 as the vehicle to do it in.
A brief recap: the new Mark IV “porcupine” 396 CID engine arrived in the early months of 1965, and was available as a production option in the Corvette and full-sized Chevrolets, in L78 425 hp form. That meant aggressive solid-lifter cam, big valves, rectangular ports, 11.0:1 compression, and all the other best goodies available at the time. All of 2157 Corvettes and 1838 full-sized Chevys were built with L78s under the hood (any Caprices?).
But Chevy also wanted in on the mid-sized action, where the Pontiac GTO had created a whole new genre. Their response was the mid-year 1965 Z16 SS396, of which only 201 were built. They were never advertised, although they got plenty of publicity otherwise. Dan Blocker (“Hoss” in Bonanza) was one of its big fans. Why Chevy didn’t put the SS396 into production in 1965 is a good question, and I’m surely not the first to ask. It was a wickedly fast machine, and those that got their hands on one were highly enthusiastic.
The ’65 Z16 was a much better car than the actual production ’66-up SS396. It was built on the reinforced convertible frame, and had unique chassis components including the biggest brakes from the full-sized Chevy line. The ’66 SS396’s chassis was mostly unchanged from the mild regular V8/SS coupes, and was decidedly not renowned for its handling or brakes. It was built to a price, to undercut the GTO.
Under the hood is the source of the 396 confusion. The Z16’s engine was rated at 375 hp, and since the legendary solid-lifter L78 375 hp 396 became available on SS396s as of mid-year 1966, and was also the top engine on Camaros and Novas during the 1967-1969 heydays, I — as well as probably a few others–mistakenly assumed that the Z16’s 375hp engine was also an L78. Not so!
It was actually an L37, made only for those 201 Z16s (as far as I know). The difference? The L37 had a hydraulic lifter cam, somewhat less aggressive in its lift and duration too. Someone correct me if I’m wrong (again), but it appears that the only difference between the 375 hp L37 and the 360 hp L34 was that the former had 11.0:1 compression and the latter had the a more civilized 10.25:1 CR. Which makes me wonder if the they had the same heads? Did the L37 have the rectangular port heads, and the L34 the oval-port heads? Or did both of them have oval-port heads? Chevy “L” experts; where are you in our moment of need?
One of the most distinctive features of the ’65 Z16 was the rear-end treatment, which was different from the cooking SS models. The black trim was unique, and those tail lights are from a 300 Series Chevelle. Don’t even ask what these cars sell for nowadays.
A couple of remaining questions and factoids on the early Mark IV engine. If the hydraulic cam L37 Z16 engine “made” 375 hp, then why was the solid lifter L78 engine also rated at 375 hp, when it was essentially the same engine as the 425 hp version in the Corvette and big Chevys. Well, the 425 hp rating was undoubtedly closer to the truth, although the Chevelle versions did use a slightly different exhaust manifold to fit in its engine bay.
And if the L78 396 made 425 hp, how come the essentially identical but larger displacement 1966 L72 427 was rated also at 425 hp? According to some sources, Chevrolet fully intended to give the L72 a 450 hp rating, which it undoubtedly actually made with its extra 30 cubic inches, but then got cold feet as the insurance industry was beginning to raise the issue of big hp numbers in a big way. Realistically, the insurance industry was the primary source of all the hp rating “gaming” that went on for the next several years, like the 430 hp L88. With its 12.5:1 CR and other race-ready parts, it undoubtedly made closer to 500 hp.
I’m going to put these engines right up there with politics as something where I listen to the conversation but put no great amount of belief in the label.
L72 for president.
The elitists run this country. What we need is representation for the common man.
327/Powerglide in ’12. The revs we need and the torque multiplication we want.
+1
+2
The reason the 1965 Corvette L78 396ci was rated at 425hp verses 375hp on all other L78 Chevys(i.e. Camaro,chevelle,nova,etc.) is the HP reading was taken at 6400rpm verses the 5600rpm used by Chevy on most Hi-Perf Engines.
The reason for this was the Corvette already had the optional L84 327ci Rochester Fuel Injected engine which was rated at, you guessed it (375hp)
It wouldn’t have been a good marketing strategy to be introducing a new BB Engine that was almost 70 cubic inches larger than the SB L84 and be producing the same amount of HP(375). It was just easier to buzz the solid lifter engine up to 6400rpm and use that stat. This was confirmed to me by both Larry Shinoda and Jim McClenahan decades ago. The L78 used in the 65 Corvette was the same engine as in all other L78 Applications(excluding L37 396) with the exception of some different exhaust manifolds used on other models. The 1966 L72 Corvettes were designated 450hp up til October 65 on the Paperwork and Air cleaner decal then changed to 425hp there after. They were the same identical engine. Same scenario as in 65; If the new 427ci being 31 cubic inches larger and still only producing the same HP numbers as the L78 396 wouldn’t have proved to be a wise marketing strategy. Insurance Companies at that point weren’t figured into HP Ratings, that started in 67 with the L88 …
The L-78 396 in the 65 corvette and 66 to 70 Chevelle ss was the same motor. I recently read an article in Muscle Car Review Sept 16 entitled “Seriously Underated.” It was on a bone stock rebuild of a 69 Chevelle SS L-78 396 that was put on the dyno before going back in the car. The results with open stock exhaust manifolds were 425hp at 5800 rpm. this was the same motor that was installed in the 65 Chevelle Z-16 except for the Hydraulic Cam. That was still a pretty hot cam and it is doubtful it would have affected the output much, maybe 10-15 hp. The Chevelles were under rated both for insurance reasons and for more favourable NHRA class positions and because Chevy always wanted the corvette to have top billing.
The L-72 427 had it’s rating lowered in 66 from 450hp to 425hp for insurance reasons as well. The L-88 427 was under rated at 430 hp in 67 to be under the 435 hp L-71. Chevrolette was not trying to avoid high insurance rates for buyers. It was trying to discourage purchase of L-88’s by everyone except racers. There was also a radio and heater/defrost delete to further make it unattractive as possible to the high performance street customers.
Gentlemen, I have a question:
I have a 1968 Impala Custom Coupe with the original 396 Turbo Jet 400. I don’t seem to be able to find very much information about this particular combination. I have found info on the Custom Coupe and on the engine but I have never come across them in a single vehicle.
Can anyone help me with any information regarding my car. Namely, what version of the 396 is this (L78?) and how many Impala Custom Coupes were produced in 1968?
Any information at all would help. I know very little about cars, collectors or otherwise.
Thanks guys.
link to 1968 brochure
Joseph do you happen to live in california? In ’74 I owned that very car. 68 396 400 turbo, black vinyl top custom impala. Hand me down from father in law after he crunched a fender. Went to buy 2in to 3.5in collector Doug Thorley exhaust and discovered there wasn’t any smog pump or tubes to the manifold. when I ran the number the engine was manufactured in 65 so factory smog it the same, 65. At that time I put in a edelbrock mileagemaker cam with a steering strip shift kit in the turbo 400. Lost the car 3yrs later in a divorce. I know she sold it and bought a 77 mgb. Hope she got what she’s bought. I always wished I could find that car. It was the most fun I have ever had in drive, I’m really a stick driver. That second gear scratch never ceased to amaze me
Joseph, this web site didn’t let me edit…that was a street/strip kit in the turbo 400. Not a steering.
Squeezing 375hp out of a 327 was a big strain on the small block. The big block could do that better thru cu. in. displacement. On the other hand, the big block was a lot heavier on the nose of the car. So, both have their pros and cons.
I couldn’t care less about the engines – give me a six with a powerglide, I don’t care, I just want one of those Chevelles! Preferably the yellow one…
I like the yellow, but also wouldn’t mind one in Evening Orchid. White bucket seat interior, in either case.
Here’s my red 65 396/425. Body off rotissarie restoration Georgia car
what would the z16 convertiable be worth restord
“As usual, it was a commenter (Terry Boyce) who pointed out that I had made a commonly repeated mistake…”
This Terry Boyce?
http://www.amazon.com/Terry-Boyce/e/B001HPKAWA/ref=ntt_athr_dp_pel_1/192-7540732-1695457
I have a copy of his Chevy Super Sports book that I bought in the early ’90s, just like the one at the link below. I think that was where I first became aware of the Z16’s existence.
http://www.amazon.com/Chevy-Super-Sports-Terry-Boyce/dp/0879380969
I’m assuming so. He’d certainly be one to know!
Paul, you asked if there were any differences in the L37 and the L78 and I responded several years ago that the only difference was the cam and lifters. The engine had square port heads FYI. and I believe (after building a later model 396 for my 65 Chevelle) that it may be possible for the L37 to have had a smaller pan. When I tried to install this engine in a production 65 the pan hit the steering and I had to seek out a smaller (Chevelle) pan which works just fine.
My Jack-of-few-trades self enjoys underhood shots of 60s-70s non-Mopars. Alternator and oil fill on the right?! Wiper motor on wrong side of master cylinder? Is the distributor in the trunk? 🙂
Glove compartment — easier to replace 🙂
LOL! …and the thermostat housing is bolted to the intake manifold, like a 318.
I remember that the ’65 Chevelles were more popular with young Hot Rodders in the late 60’s. Rarely saw a ‘hopped up’* 64. Same with the ’69 was more liked than the 68’s. But 1970 Chevelles stole the show, were all over HS parking lots.
* Loud exhaust, custom mag wheels, jacked up rear end, fuzzy dice, larger rear tires, etc.
“After about the fifth or sixth Chevy engine L-code variation, I start to get a bit glassy-eyed.” – – I agree. Too many Ls and I start to do Zs. There are certainly a lot more variations than I ever knew about, and I never knew about this 1965 model.
I’d much rather see a 400 or 455 Buick or Olds engine ;).
Nice beast ! I’ve always liked the clean, smart lines of the ’64-’65 Chevelles
Me too. I was looking for a new car in late 1964, and the Chevy salesman was good at his job, but he didn’t have a four-speed car I could drive. I looked at Mustangs and Barracudas too, and bought a Barracuda. The Chevelle demonstrator I drove was a pale yellow on black 2-door hardtop, a very good looking car.
it’s funny how automatic transmission by 1964 was something so taked for granted in the US, here in Italy it’s still somehow despised by most of the car enthusiasts but I guess it’s just a cultural matter…anyway gimme a Z-16 Chevelle anytime…I want the asphalt apologize to me anytime I press the gas pedal a little harder than usual 😀 !!!!
Four speed with a 273? I’d like to hop in that car right now!
Not me. Of the quartet of ’64-65 GM intermediates, by either design or happenstance, the Chevelle easily came up on the short end of the styling stick. The worst perpective is the rear 3/4 view where that blocky rear end, small tailights, and half-covered wheel arches are most evident.
It’s not so much that the Chevelle’s styling was bad, it’s just that the intermediate offerings from Olds, Buick, and (especially) Pontiac were so much better (at least in appearance).
No, keep them Rat Motors coming! One of the great engines coming out of the sixties. I often wonder about the internal politics of GM/Chevrolet. Did GM or Zora Arkus Duntov put the brakes on any Chevrolet model beating the Corvette in horsepower ratings? I’ve no doubt the insurance companies were confused by these different engines and their published hp specs.
I’m a fan of the 66/67 Chevelle body but have to admit that the 65 Chevelle SS 396 is one beautiful automobile!
I figure there were two forces behind the confusing, questionable horsepower ratings of the 1965 396 engine lineup: the unexpected success of the GTO and, as pointed out, an edict that ‘No GM car shall be faster than the Corvette’ (probably courtesy of Duntov).
By 1965, it was painfully apparent that Chevy needed to get in on the burgeoning intermediate musclecar market created by DeLorean and the GTO over at Pontiac. The small-block 1964 Chevelle SS wasn’t going to cut it.
But Chevrolet had to walk a fine line between having a car as powerful (or more) than the GTO, but not so powerful as to be faster than the Corvette. Combine this with how Chrysler had no such issue with offering the 440 big-block in their intermediates, and GM had a real marketing problem.
The only offsetting factor was that Ford had yet to come up with a decent big-block (and wouldn’t until the 1968 CobraJet) in the intermediate Fairlane since the ‘high-performance’ 390 was widely regarded as a stone.
That’s where the 1965 Z16-exclusive L37 396 came in, and why it was a low-production ‘one-hit-wonder’. The next year (1966) would see the Corvette get the 427 while the Chevelle SS396 would get the lower-rated 325hp L35 as standard equipment, with the 360hp L34 and 375hp L78 (formerly rated at 425hp the year prior) as options.
GM would also implement the over 400 cid engine ban in intermediates (a ban that wouldn’t be lifted until 1970), effectively making the 427 Corvette the fastest GM car by default. This, along with the ‘new’ 396 engine lineup, seemed to solve all the issues, with the proof being that the SS396 would eventually eclipse the GTO as the best-selling musclecar (but it would take until 1969 to do it). Ironically, the GTO would fall to third in the same year, with second best going to none other than the Plymouth Roadrunner.
But from 1964 thru 1968, the GTO would be number one (if only in sales and not actual performance). There’s also the question about the GTO being number one in 1964-65 because it was just an ‘option’ and yet to be its own separate model. For that reason, the separate Chevelle SS was technically superior in sales. But the reality is that the 1964-65 GTO ‘option’ sold more than the Chevelle SS ‘model’ of the same years.
Another rather interesting debate would be what was the difference between the hydraulic-lifter 325hp L35 396 and the 360hp L34 396 that gave the latter 25 more horsepower? By most accounts, it was nothing more than a different camshaft.
In simplest terms:
L35 – hydraulic lifters, mild cam, 2-bolt mains, iron crank
L34 – hydraulic lifters, hotter cam, 2-bolt mains, iron crank
L78 – solid lifters, hottest cam, 4-bolt mains, steel crank
I don’t know where the Z16’s L37 396 falls in this hierarchy. Considering that the L37 had the beefed L78 internals with a hydraulic cam and special exhaust manifolds to fit in the Chevelle’s engine bay, it probably falls between the L34 and L78.
One other point aside from the 400 cu. in. limit was the 10 lb/advertised hp rule for everything other than the Corvette, which led to some really improbable advertised ratings.
That kicked in for 1967, which explains why several engines suddenly had lower ratings than in 1966.
the 360 HP had a larger Holly carb…the 250 HP had a smaller Quadrajet
just remembered….the 360 HP also had bigger heads…larger ports..
Can’t leave out the heads. All the solid lifter mark IV BB got the rectangle port head, as did the L37. All the lessor BB got the oval port heads. It’s highly doubtful the L37 could match the L78 peak hp.
The L37 would have flirted with valve float around 5800 rpm where the L78 would be good to at least 6500. It’s debatable if a production L78 would have made much more power above 5600 but a blueprinted one certainly could. At the time Chevy even admitted there could be up to 20hp difference between the identical engines on the lot.
None of the oval port 396’s engines performed exceptionally well by that I mean they couldn’t out perform the hotter 327 or 350’s even though they 100ft-lb torque advantage.
There were subtle differences in these heads and cams from year to year but the L78, L72, LS6 and their close cousins shared basically the same heads and cam for any given year. The ZL1 and LS7 got slightly more aggressive cams although I read that late 69′ L72 actually did get the same cam as the ZL1.
Let’s really confuse every one by bringing up the subject on how there. were two “396’s”.
One was ‘396″ cubes and the other 396 was (if I recall accurately) called 402 cubic inches. I’ll let you readers chew on that a bit to see if anyone can further explain what I’m talking about (evil grin).
Yes, from 1970 to 1972, Chevrolet bored out the 396 a bit to 402 cu. in., but since they had already built up quite a bit of name (number?) recognition for the 396, they frequently continued to describe it that way.
To confuse matters further, during the same period there was also a small block 400, which was basically a bored and stroked 350.
We’ve actually had several discussions on that issue here lately, so I think our readers probably have sore cheek muscles for the time being.
Paul,
Your comment in sept. 2012 as to whether the 65 chevelle Z16 had the round or rectangular intake ports.
I owned one and rebuilt it a couple of times, ran it hard around Saint Louis Mo.
It did have the retangular ports.
That was always my favorite automoble,
Someone else must have liked it more, because it was stolen back in 72.
Thanks for confirming my suspicion, and sorry about your loss. That must have hurt. Probably still does 🙁
ZZZZZ
LLLLL (That’s the sound of my tongue hanging out the side of my mouth as I ZZZZ)
I’d vote for 327/4speed in ’12. More ratios for torque multiplication.
Mark Meekins is the expert on these cars.
http://www.z16chevelle.com/No.1%20Z16%20Chevelle%20Report.htm
http://z16chevelle.com/
All your questions will probably be answered here.
And if you want to compare the horsepower of that engine with today’s engines, its actual net rating as measured today would be about 280 horsepower, about the same as an ordinary V6 has now.
I am doing a frame off restoration on 65 chevelle ss convertible, 283 2 brl auto, matching # car. My questio is do i leave it stock or clone the Z16
Leave it stock! there were only 200 Z16 Chevelles built. There is mention of a Z16 convertible but NO documentation.
I still have my 65 Chevelle SS hardtop. It spent only a short time as a “stock” engined car. And “NO” time behind a GTO. It currently has the original 283 installed with Weiand Blower and Erson blower cam and kit, etc. I backhalf’ed it in the 80’s when I dragged it with a 600 HP BBC. It is in my garage with only 43,000 miles on it and ready when ever I am to get in trouble.
The L37, L78 and 396/425hp 65 vette question is simple. The Corvette had a first generation camshaft along with headers and side pipes that made 50 more horses. The L78 had a second generation(or design) camshaft that had less duration. The L37 Z16 camshaft was of course a hydraulic lifter that was wilder than a 360 hp camshaft for the next production year of 1966. You also have to remember the heads were first design rectangular port closed chamber with 2.19/1.72 valves. 1.84&1.88’s didn’t show up till later. Camshaft numbers are L37/Z16 3873844 duration 342/356 lift .461/.500 L.S.113.5* overlap 122*. L78/375hp solid lifter 3904362 duration 316/302 lift .5197/.5197 L.S. 114.5* overlap 80*. 425hp 65 Vette 3863143 dur. 336/336 lift .5197/.5197 L.S. 114* overlap 108*. I have open and close values if anyone needs them. Hope this helps!
Not trying confuse anyone, and I know that both solid lifter cams were L78’s. Also the 3863143 with more duration had an groove in the rear journal for oiling purposes and it was made in 1965 & 1966. 3904362 did not have the groove and was made 1967-1971 in production cars. All numbers are from Chevrolet service manuals with copyrights dating from 1966 to September 1970. The L78 375hp rating was all about the insurance. A friend has a 67 375 horse and he should know. He is a guru when it comes to racing. Like the guy said about the L88, it does make 430 horses I promise!
Jimbo, are you still active on this site? Have a few questions about your post.
I was the first owner of the ” popular hot rodding” Z16. The L 37 motor is exactly the same as the 425 Hp. model less the cam and lifters.
If anyone recalls, early ’66 L72 Corvettes left the St. Louis factory w/450hp decals affixed to their air cleaner lids. A decal change to 425hp was later implemented.
Yes, I saw one of those at Crusin’ on Grand in Escondido. It was for sale.
’65 Caprice, YES. My mom bought a brand new ’65 Caprice with a 396-power glide. 4-door hardtop, blue and white.
It was a POOCH !
This question may have already been answered here,but I didn’t see itif it was.So how many of the Z16’s are really known to still exist today?
I worked at the Leeds chev plant in KC & they built the 201 396 Chevelle so they could race them on the big circle tracks like Daytona & be legal to do, I tried to get one but no way, so I got a 1966 Chevelle 360 hp they didn’t have the aluminum manifold but I always thought mine had one of the 65 blocks in it on the right side of the block it had Hi PER stamped on it & it was a 4 bolt block & I looked at a lot of others that said 360 hp but they were stamped PASS
Does anyone remember Grumpy Jenkins R.I.P. running his L-79 327 350 hp Chevy II In “A” stock and beating all those Hemis. That was greatness. It was called Grumpy’s Toy
Mike Crivello, we must have pasted on the street sometime in those days. I lived in St. Charles, Mo and in the early winter of 1969 bought a black 1965 Z16. In mid summer 1969 I had the opportunity to swap the original engine for a fresh, blueprinted L88 427 (bigger engine even bigger mistake swapping my original engine). I traded the car in on a new 1969 Yenko Nova which was an even bigger mistake than swapping engines in the Chevelle, the Nova was a piece of junk. I sold the Nova in early 1970 and it was stolen shortly there after and ended up in a salvage yard. Bottom line I always like the Chevelle, more so after I sold it.
This run of cars were sold to GM management as ‘Police Specials’ and was specifically approved by Ed Cole. What is not widely known is that Buick had a run of 200 ‘Police Specials’ approved for 1966 as a GS. Because of supply issues the Dec 66 Jan 67 run was pushed to Feb and then to March and in the end only 12 of these cars were produced with a special 401 ci package rated at 425hp. They also used a special TH350 with a unique torque converter and internal valve body.
http://thepandatrap.com/tyler/buick/FF01_Before.jpg
My father worked for Chevrolet at the Zone office in Los Angeles during this period. At that time, mid-level management traded in their company cars every 3000-5000 miles. So in late ’66 or early ’67 he ordered a red SS396 Chevelle 4-speed close ratio with a solid-lifter 425 hp option. It indeed had a 425 hp sticker on the air filter enclosure. I can date this because he drove it just before I turned 16 in May of ’67. It was a beast, and I believe my father knew the person who ended up buying it, because my father said the owner couldn’t keep clutches in it. Since he commuted through LA traffic, my father never again ordered a 4-speed company car. I wonder how many of the 425 hp optioned cars were made. Was it COPO?