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60s-70s big Chevrolets vs. big Fords



  • ndancendance Posts: 323
    (remember, this a 1970 model) is a non-Holley carb (Autolite maybe?), painted intake manifold engine (likely to be iron).
  • argentargent Posts: 176
    The 428 Police Interceptor had an Autolite 4300 four-barrel. The Police Interceptor had an aluminum manifold only through '68. It was not the same as the 427 manifold, I don't think, but it was similar. After December 1968 it was switched to a (presumably cheaper) cast-iron manifold. I couldn't find cam specs, but rated power and torque (SAE gross) were 340 hp @ 5400 rpm and 459 lbs-ft @ 3200 rpm. (I also saw a 360 hp rating at the same RPM, but that may have been for pre-'67 engines without the Thermactor.) Thermactor-equipped 390 GT engines rated either 320 hp ('67 and '69) or 325 hp ('68) at 4800 rpm and 427 lbs-ft of torque at 3200 rpm.
  • speedshiftspeedshift Posts: 1,598
    I did some research too and the 390 PI seems to date from '61-3. The block is apparently the High Peformance 390 block with two bolt mains but with more webbing, larger oil galleries and "a pressure relief valve at the end of the main oil gallery to direct more oiling back to the crankshaft (especially on cold start-up)". This sounds like the right block because "since only mechanical camshafts were used in these engines, they have no lifter oil gallery passages". The block has HP cast behind where the generator is mounted.

    I also see a reference to a "hi-perf and police original equipment" crank, identical to the regular version but with grooved mains and larger harmonic balancer, available after 1/15/62.

    The 390 PI used the same rods as the 390HP, 406 and '63-4 427. '66-70 PIs used a rod with a slightly thicker beam and rod bolt, shared with the hydraulic cam 427 ('68 only) and 428 CJ.

    It looks like the early mechanical cam in 390 PIs was C3AZ-6250-T with "only" 282 degrees duration, .440" lift and 54 degrees overlap. Compare that to the Medium Riser 427's 306/.500/78, pretty manly specs. I can't tell what later PIs used but the hydro GT cam would be a good bet.

    My source says the PI intake manifold is the same as the "special order" 428 CJ aluminum version, although the regular 428 intake is identical but cast iron. The CJ used a 735 cfm Holley. IIRC the Autolite 4v came in 480 (small block) and 600 cfm (big block) versions and the latter may be the 4300 used on the 428 PI.
  • speedshiftspeedshift Posts: 1,598
    Here's some horsepower ratings:

    '61-5 390 330 hp @ 5000
    '66-9 428 360 hp @ 5400
  • speedshiftspeedshift Posts: 1,598
    Tariks's El Camino reminds me of a '68 Caprice coupe I saw a few days ago--it's the taillights in the bumper. I still remember the first '68 I saw. I thought it was really radical for a Chevy and it still strikes me that way today. Huge chromey grille with hidden headlights (Caprice), traditional six taillights but set in the bumper.

    This one was very clean, kind of a grey blue with black vinyl top, and with the Caprice roofline that says "personal luxury car" (or maybe it's "rich Corinthian leather"). It certainly got my attention.
  • grbeckgrbeck Posts: 2,361
    Those Caprices were pretty classy for a (relatively) low-priced car.

    The family who lived almost directly across the street from us owned a 1968 Impala Super Sport fastback with a four-speed. I still remember the sound of that engine (the exact engine escapes me). At the same time, my grandmother's "gentleman friend" had a 1968 Bel Air four-door sedan with dog dish hubcaps, a three-speed on the column and a six cylinder engine! Kind of amazing to think how versatile the full-size Chevy was even in the late 1960s. It could be a stripped family sedan, luxurious coupe or sporty fastback.

    In many ways, I think the Caprice and LTD undermined Cadillac and Lincoln. By the early 1970s, there really wasn't anything on a Cadillac or Lincoln that you couldn't get on a properly optioned full-size Chevy or Ford.
  • rea98drea98d Posts: 982
    "By the early 1970s, there really wasn't anything on a Cadillac or Lincoln that you couldn't get on a properly optioned full-size Chevy or Ford."

    Except maybe the snob appeal of driving a "real" luxury car...
  • andre1969andre1969 Posts: 21,606
    ...I think I'd actually prefer an Olds 98 or a Buick Electra over a Caddy DeVille. Somehow, the interiors of those Buicks and Oldses almost end up looking ritzier than the Cadillacs!

    I know that nobody buys these kinds of barges for performance, but it also seems that an Electra or 98 with its corresponding 455 V-8, and lighter mass, might be a slightly better performer than Caddy with a 500. But then, you still lose the snob appeal!
  • The Cadillac 500 was kind of a dog, at least in relation to its CID. I think it was only pumping out something like 190HP (Class, compare and contrast to HP per cubic inch of a '57 Chevy fuelie). It had lots of torque though, as befits anything with large displacement.
  • lemkolemko Posts: 15,077
    ...a 1975 Cadillac Sedan DeVille in Georgian Silver with a dark blue top and dark blue leather interior. It had the 500 cid V-8 (8.2 litre). It was rated at 210 hp, still a dog for its displacement, but the car still had a lot of power and accelerated quickly. It did have enough torque to tear a giant redwood out by its roots.
  • andre1969andre1969 Posts: 21,606
    ...on a website, and the Caddy 500 had 380 ft-lb of torque! Anybody know what an Olds or Buick 455 had by that time?

    Oh yeah, Lemko, if you've never seen it before, check out this website:

    The guy who put it together is a real Cadillac nut, and has tons of pictures, info and tidbits on it.

  • I drove a '76 Eldo earlier this year for a couple hundred miles. I think 60s Chevies were much better in every respect.
  • andre1969andre1969 Posts: 21,606
    ...anybody know how fast a '77-'79 DeVille with the 425 would do 0-60? I vaguely remember Motortrend's 1977 Car of the Year, a '77 Caprice with a 350, doing it in 10.8 seconds.

    I wonder if any of GM's downsized full-sizers in the late '70's would've been able to break the 10-second barrier? My guess is that a Catalina with a 400 or an Olds Delta with a 403 might have the best shot. But then they tended to play with gearing back then, to give weaker engines an advantage, and hold back the bigger engines in a lame attempt at improving fuel economy.
  • ab348ab348 Dartmouth, Nova Scotia, CanadaPosts: 1,553
    Yeah, my '79 Electra has the 403 but a 2.41 rear gear. Off-the-line acceleration isn't it's strong suit.

    In '77 and '78 you could order a base Delta 88 coupe (lightest model) with the 403. Assuming you could order an optional rear gear, that probably moved out reasonably well.

    2011 Buick Regal Turbo, 1968 Oldsmobile Cutlass S Holiday Coupe

  • andre1969andre1969 Posts: 21,606
    I've noticed that in some cars, to compensate for a tall rear gear, they put a shorter ratio for first gear in the transmission.

    Let's suppose you had one car with a 2.94 rear and 2.45 first gear, and another with a 2.45 rear end but a 2.94 first gear. All other things being equal, should they both take off about the same? At least until they hit 2nd gear?

    I think first gear on most GM trannies was 2.48:1, until they came out with really tall rear gearing. Then they went to a 2.73 first gear. At least, I've seen both first gears mentioned on that Caddy website I posted earlier. They also listed a variety of rear ends, from something like a 2.24 on up to a 3.08.

    I'd imagine if you could get a 2.73 first gear with a 3.08 rear end, your typical smogged '70's cruiser wouldn't be too bad, would it?
  • A '77 Deville would probably be right around there, 0-60 in anywhere from 10 to 12 seconds. It's horrifying to contemplate, but a '77 Deville would probably beat a '75 Camaro 350.
  • grbeckgrbeck Posts: 2,361
    I don't know what the gearing was, but my parents' 1976 Oldsmobile Delta 88 had a 350 V-8. That car was a dog in the acceleration department (although it was very reliable). They traded it in on a 1982 Oldsmobile Delta 88 that was just as slow. (I think it had the 307 V-8; it definitely was not equipped with a V-6 or the infamous diesel.) People say, "They don't make them like they used to." When it comes to cars of the mid- to late-1970s and early 1980s, I say, "Thank goodness!"
  • andre1969andre1969 Posts: 21,606
    ...but then again, Olds was still offering that little 260 V-8 that had all of 100 hp in 1982. I'm sure a few of those found their way into the Deltas!

    A friend of mine used to have an '82 Cutlass Supreme sedan, with the 260 V-8 and the 3-speed automatic. One night we did a little drag race out on the highway, when I had my '86 Monte with a 305 and 4-speed automatic. I was actually suprised at how well that Cutlass did. My Monte was still faster, but not as much faster as you would think, considering they both weighed about the same yet the Monte had 50 more hp (dunno about torque though...I think the 305 had 245 but I don't know about the 260...maybe 210-220 ft-lb?)
  • the 390 that was first put into the Mustangs had the simple problem of being strangled off.........small carb,restrictive exhaust,lose those two, and the 4bbl 390 WAS a good runner............remember, they were rated at 300+ hp
  • explorerx4explorerx4 Central CTPosts: 9,459
This discussion has been closed.