Land yacht wonderings

A few threads on here lately have gotten me thinking back to the days of smog, disco, baby broncos, and land yachts. Especially land yachts.

With those 500+ cubic inch anchors under the hood, how did they make a measly 180ish horsepower? Were they just neutered for emissions or made to be weak, I guess is what I'm asking.

Are the blocks .... adjustable in the modern landscape we live in? Or should they just be left to return to base elements?

Maybe I just don't understand terminology and technology in motors, OK I really don't, but say an 8.2l 500cu inch Caddy V8 puts down 180bhp while a Viper holds an 8.6 512 cu inch V10, and puts out 640hp. (the only other 8 liter I found in current use is in the veyron, and I don't even want to go there). I understand different requirements for the vehicles from the factory and living in a different time, but half a liter of fuel and 2 cylinders does not add up to 460hp.

To me, it sounds like the displacement is already there, couldn't one bore and port an old anchor to get more respectable numbers? Maybe piston swap, valvetrain, and oh crap is this getting expensive and complicated fast. Or is there a cheap way?

I know a lot of this stuff all went away when scrap was high, and the cash for clunkers program and whatever else, but it still to me seems like there would be a bunch of old huge blocks sitting around waiting for a purpose. Can they handle boost? Do they respond to Nitrous?

I guess weight would be an issue as well.

On the other side of this coin, those engines had big footprints, and left big holes under hoods. Shells are still cheapish and plentiful in certain parts of the country. Can modern SBC and SBF move the old things? Are modern drivetrain components even big enough to fit?

Can they even be made to turn? All I've really seen done with them are restorations to stock or converted to Low Riders. Is that really all that land yachts can be?

I'm not picturing an autocross champion, but a highway cruiser, or Grand Touring competitor maybe.

Holy crap, I never new the El Dorado was FWD in the 70's.. I don't think I want one now. So there really is no point to this, but I typed it all up and didn't want it to have been for nought.

Smog restrictions. Poorly designed heads. Low compression. Restrictive exhaust. Carburetors instead of EFI. "Tuned" for economy, not power.

40 years of development in internal combustion means that the antique stuff just can't measure up. So find a RWD barge and convert it to LSX and enjoy. Trying to get real power (or economy, or durability, etc) out of the boat anchor will just frustrate you.

My .02

The big block Caddies were about the same weight as a SBC, if I recall. Also, while 180 HP might be the number, it was available practically at idle, so torque was through the roof. I had a '72 CDV with a 472 motor, and it would stay up with a new 1979 Corvette off the line.

Compression got hammered in 1970 or 1971, I think, dropping from like 10 to 8:1 for emissions. The FWD Eldo didn't have any issues related to the FWD, really. Axles or seals at like 80K miles, but that's maintenance. The transmission was otherwise a big THM. They put the drivetrain in the big GM motor homes of the mid-late 70's. In 1975, I think all the Caddies had the 500, not just the Eldo, so the 1975 Caddy CDV was a rear wheel drive 500. 6MPG around town was expected. I think you could get 12-14 on the highway at 55MPH if you were real careful.

I owned a 1976 Olds Cutlass briefly. Olds 350 under the hood and 170 horsepower. Torque was okay, but that thing labored mightily to get over 75 mph. Oh, and 12 mpg around town, 16 mpg highway.

The culprit was technology lagging behind emissions laws. IMO, it would take heads, pistons, camshaft, and exhaust to make worthwhile power. Nothing wrong with a Quadrajet, as long as it's set up properly.

Even pre-smog they really weren't strong because they weren't efficient. From the intake to the exhaust, and everything in between. The holy grail back in the day was 1 hp per cubic inch. Rarely achieved. Today, we can get multiple HP from 1cc.

the best thing about big displacement engines is they respond more to each mod then smaller displacement engines, obviously at the cost of fuel. so any small block recipe (or really any engine i guess) of heads, cam, intake, and exhaust make the big blocks live up to there hype. But another concern is that pretty much any big block part has a premium price over there small block brothers

It's a combination of bad heads, primitive emission equipment, poor (for performance) tuning, restrictive intake and exhaust parts, and other cost saving measures that made engines of this era suffer. I have experience with Olds and Pontiac engines from this time period. Both brands had fantastic engines in the 60's and early 70's, but were shells of themselves by the end of the 70's.

For Pontiac, the two most common engines found in land yachts (and performance cars) during that time were the 400 and 455. The 455 lasted until 1976, and the 400 made it up until 1978 (1979 in some 4-speed equipped Trans Ams). The limiting factor on these were the heads and cams. The early 70's cars mostly got "big valve" heads (2.11 intake/1.77 exhaust) and fairly aggressive cam profiles. They also had chambers designed for high or moderate compression ratios. By 1976, the 455 had a 7.6:1 compression ratio mainly due to the "small valve 2.11/1.66" heads with giant 124.51cc combustion chambers. The cams were weak, too, and they had an emissions-tuned Quadrajet and a terrible timing profile.

Luckily, Pontiac engines are like Legos. The 400 in my Trans Am is a 1974 smog block with a '68 350 nodular crank and rods and 1971 GTO heads. Those heads, along with a few other castings, have the "big valve 2.11/1.77" valves and smaller chambers for a higher compression ratio. On a factory 1971 400, it produced 8.5:1. I'm somewhere around 9.2:1 with my pistons. Also of note: there are no "big block" or "small block" Pontiacs. The 326, 350, 389, 400, 421, 428, and 455 all share the same external dimensions. The difference is the main journal size. The 326, 350, 389, and 400 all have a 3.00" main, while the 421, 428, and 455 have a larger 3.25" main journal.

Olds motors are similar. The mid-late 60's-early 70's engines were stout. Unlike Pontiac, they had "big block" and "small block" engines. The big block engines (400/425/455) had a taller deck height while the small blocks (330/350/403) had a shorter deck height. Starting around 1976, GM got stupid and started taking material out of the main webs of their Olds V8's, and those engines are not the best to build. They do make stud girdles and other things, but I'd avoid them if possible. The 403 I had in my Trans Am was one of these engines.

Again, you can make great power with a head/cam swap. The big block heads all have letters cast into the heads on the passenger front above the exhaust ports IIRC, and the small blocks have numbers. Late small blocks have both numbers and letters (the 403 has 4A heads for example). If you choose to build something like the 403, you can swap on heads like the 1968 350 #5 castings, which flow great and have the better combustion chambers to achieve decent compression. Big V8's will respond the same way to earlier big block heads. The C casting heads are the hot ticket there, but are expensive!

For cruising purposes, an intake, cam, timing set, re-curve of the distributor, exhaust system, and carb adjustment will do wonders for any of these engines. That's what I would do if I ended up with a land yacht, and it could be done in a weekend!

I was running the numbers on the old 9C1 Caprice I had. It made 190hp 290tq out of a 350. Redline was around 5k but tit stopped making power long before that.

The LR4 (4.8L) make 285hp (in the later variants) and 295tq with a redline of 6000rpm and makes power up to that point. On top of that, it uses aluminum heads, water pump, plasit intake etc so it's lighter to boot. So you lose 50lbs, pick up 95hp and don't lose any torque plus get an extra usable 1500rpms.

To make them meet emissions and run on unleaded gas in a hurry they did all kinds of awful things as mentioned above, e.g. in a smog Ford 460 there's like 50hp hiding in the cam timing alone. Those early catalytic converters were also very restrictive (box full of pellets), you probably gain 20-40 hp deleting them.

With my limited knowledge it just seemed like there was a lot being left on the table, but I never really see anyone do anything with the old stuff, so I was curious as to why not.

Not having grown up in that time, just seeing/hearing all the old stories almost had me thinking am exhaust and head job could make something that would cruise all day at 80 and not take half the day getting there.

I can barely afford my project cars as is, but an old caddy or Lincoln convertible has always been a bit of a dream. 2 lanes wide, a block long, just set on comfort, and maybe able to spin the tires over on occasion.

In reply to RevRico:

I'd bet that increased compression, a fair bit or porting/polishing, and a cam would do wonders. If you wanted to go full hog, you could probably regain some fuel economy by switching to EFI.

RevRico wrote: With my limited knowledge it just seemed like there was a lot being left on the table, but I never really see anyone do anything with the old stuff, so I was curious as to why not. Not having grown up in that time, just seeing/hearing all the old stories almost had me thinking am exhaust and head job could make something that would cruise all day at 80 and not take half the day getting there. I can barely afford my project cars as is, but an old caddy or Lincoln convertible has always been a bit of a dream. 2 lanes wide, a block long, just set on comfort, and maybe able to spin the tires over on occasion.

The pre emission days cars are still out there at semi-reasonable prices. My 63 Continental with a mostly stock 430 and a Carter (meh) would absolutely roast the tires and move that big car better than it should.

As far as I can tell people don't do anything with that stuff because it isn't popular, everybody wants to hot rod 60s 2 door muscle cars, the 70s stuff isn't "cool" (a few exemptions aside, e.g. F body), and making the big stuff faster has never been a huge priority.

RevRico wrote: With my limited knowledge it just seemed like there was a lot being left on the table, but I never really see anyone do anything with the old stuff, so I was curious as to why not.

The engines themselves left a lot on the table, but you don't see much being done with the entire car because the engines were often more desirable than the body shell. There are a couple iffy engines, particularly if you're looking at the smaller end of the V8s, but the 400+ cubic inch V8s have real performance potential.

I've been noticing that the '79-ish Thunderbird is looking better to me these days. I think I'm sick. A new 5.0 Coyote even connected to an autotragic would be fun for cruising.

RossD wrote: I've been noticing that the '79-ish Thunderbird is looking better to me these days.

RossD wrote: I think I'm sick.

If it is any consolation, I think you are sick too

Jumper K. Balls wrote:

Dang, that's hawt!

RevRico wrote: A few threads on here lately have gotten me thinking back to the days of smog, disco, baby broncos, and land yachts. Especially land yachts. With those 500+ cubic inch anchors under the hood, how did they make a measly 180ish horsepower? Were they just neutered for emissions or made to be weak, I guess is what I'm asking.

Neutered is a good word. When the emissions requirements hit, manufacturers had no idea how to go from the anarchy of muscle (which wasn't that muscly) to suddenly having to conform. The result was 8:1 compression instead of 10:1, tiny cams, and dished pistons. The Viper makes 640 hp because of science; 40 years of technology.

The other compounding factor was that around the same time, HP ratings went from Gross to SAE net. A 360-hp Pontiac 389 really only made about 275 hp by today's standards. Gross HP was also measured on an engine stand with 55 gallons of coolant, no accessories, headers, no mufflers, a carb velocity stack... and even then since there were no real standards, manufacturers kinda slapped a good number on it sometimes. The LS6 454 and DZ302 made considerably more power than advertised, but insurance companies started complaining and Chevy might have lied a little bit. The Buick Nailheads were overrated. The original dyno tests for the first few years were disappointing, so they just said they had more.

Displacement unfortunately is not just equal across the board. The thing with Caddys is architecture. Like most engines of the time they weren't designed for big power like they are today. They took an engine and made the architecture sufficient for 185 hp. Things like valve angle, port radius, chamber design, etc just aren't like the CAD-engineered clean slate design you have in the Viper.

Having said that, yes you can make it turn and make good power, but its not their strong suit. You'll spend really big dollars getting over 400 hp because of that architecture. Cad 500 blocks are also really high nickel blocks which makes them - which sounds great, but not for this application. You know how everyone looks for the high-nickel 010 SBC? That's fine to a point, but hard blocks + high RPMs can be disaster. A "soft" iron block can absorb far more vibes before failure because they deform. Think of it like whacking a hammer on a piece of wood versus a piece of glass. The high nickel alloy was chosen for the caddy block because it was a low RPM motor. The harder alloy paid off in wear resistance and through being able to design it with less physical material to keep it light. (yes, a factory cad 472/500 weighs about 35 lbs more than an iron/iron SBC).

Bottom line, you can make 640 hp from a Caddy 500, but it won't be a nice, smooth, streetable engine like the Viper or Veyron. It will be a lumpy, loud cannon best suited to a drag strip. Back in the 90s I built a couple. One was a tow motor for a 66 Bonneville that I chose because I couldn't afford a diesel (and there weren't many diesels back then that would have worked well other than a wheezy 6.2L or a massive 7.3L) It made about 235 hp, but even with 3.08 gears and a TH400 I couldn't keep the tires on the pavement. Torque was just insane. The other one was about 390 hp that a buddy put in an 84 chevy pickup. It was a great motor and a nice conversation piece, but he could have made more power with less money with a 454.

BrokenYugo wrote: As far as I can tell people don't do anything with that stuff because it isn't popular, everybody wants to hot rod 60s 2 door muscle cars, the 70s stuff isn't "cool" (a few exemptions aside, e.g. F body), and making the big stuff faster has never been a huge priority.

That's one of the reasons I LOVE the 70s stuff. Nobody wants it. Its cheap. Here are some of my 70's cheap scores.

I personally think Buick had the best 455 of the BOPs. Huge bore, short stroke. Making it rev is easy. Never was a fan of the Olds 455 and the Pontiac was just too heavy.

Which leads me to my NEXT 70s LUST:

Boattail, baby.

Jumper K. Balls wrote:

RossD wrote: I've been noticing that the '79-ish Thunderbird is looking better to me these days.

RossD wrote: I think I'm sick.

If it is any consolation, I think you are sick too

Toss on some black steel wheels (Aero) with some raised white lettering tires (nascar-esque), adjust the ride height a bit for more of a sporting look. Stuff the wheel wells full of tire.

My couch on wheels.

Curtis is right about the power levels being what the block was designed for. Stuff in the 50's you can get away with a little bit more. My 365 with just a cam and better carb upgrade and nothing else will roast tires for days. Transmission does not like it though and still 14 seconds to 60

It wasn't a big block but my '77 Cutlass Supreme had the 350 "rocket". The previous owner put a different cam, intake and carb on it. With a free'd up exhaust it was somewhat quick off the line and it could really haul the mail on the freeway with its factory tall gearing.

I still miss that car to this day.

I had a 71 Eldorado with the 8.2 liter (500 cid) IIRC it was rated at 385hp and 440 lb/ft of torque. It also was 21 feet long and probably weighed 4500 lbs!

Keep in mind that although horsepower ratings were low--- a lot of these cars made tons of torque. My Caddy felt a lot faster than it was, and it went down the highway like a train. Even at high-altitude it would cruise effortlessly at 85mph. I lived in Denver at the time, and I'd be able to clear the Eisenhower tunnel at pretty much any speed I liked. (although things got pretty dicy over 85mph or so) It was hands-down the most comfortable car I've ever owned. It also got single digit gas mileage around town!

Before 1971 compression was pretty high. Afterwards the automakers were struggling with emissions, and performance dropped pretty drastically. Pretty much ANY big sedan from the 60's will roast the tire (one wheel peel) off the rim---- especially if you roll through a puddle first!

A big smog era FoMoCo coupe is on my wish list.