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Thread: 1975 Trans Am (L75) 455 H.O. - The King Returns?

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    1975 Trans Am (L75) 455 H.O. - The King Returns?



    1975 Pontiac Trans Am (L75) 455 H.O. - The King Returns?

    By Pete Dunton

    http://www.ericpetersautos.com/home/...3&Itemid=10787

    Automotive history as it has been written, 1975 will never be known as a banner year for muscle cars. The GTO, Chevelle SS, Challenger, and Cuda were among some of the most famous muscle car names to bite the dust by 1975. In 1975 the only Mopar muscle car names that remained (had become Chrysler Cordoba clones) - the Plymouth Road Runner and Dodge Charger, which had sadly become underpowered luxury barges with pillowy seats. Ford had completely given up, the Mustang by 1975 was know as the Mustang II and based on the Ford Pinto platform. Though it was a sales success it was as far from a muscle car as a car could venture. The availability of only 4 and 6 cylinder motors for the 1975 Mustang II, was a big reminder of this fact. The Torino had also grown to almost Thunderbird proportions however it still packed a V8 under the hood. Sadly the Torino's largest displacement V8 was a 351 Cleveland that was very light on the horses. AMC was also out of the muscle car business by 1975. At GM things also looked grim. Oldsmobile still had a 442 and a Hurst/Olds and Buick still had a Gran Sport but these cars were so detuned, that their decals and emblems were the only similarity to their predecessors. Chevrolet also threw the white towel in the ring, by 1975 the largest displacement V8 in the Corvette was a 350 CID V8. The Camaro had dropped so far in performance and to add insult to injury, Chevrolet even dropped the Z28 from the Camaro lineup for a couple of years starting in 1975.

    Pontiac was also feeling the pinch like every other U.S. auto maker with the new EPA mandated emissions standards for 1975, lower compression motors that started in 1971 for GM (EPA mandated that all 1972 cars run on unleaded fuel, hence no more high compression motors), skyrocketing insurance rates, and the after effects of the 1973 OPEC oil embargo. Pontiac not one to give in to adversity, had beaten the odds up until 1975. The mandated lower compression engines had killed just about every high performance motor by 1972. Pontiac continued as if nothing happened and just converted to high performance low compression V8s. Pontiac high performance low compression V8 motors were so good that they could propel an almost 4,000 lbs Trans Am in the mid to high 13 second to low 14 second 1/4 mile time range. These motors were the 1971-1972 455 (CID) H.O. V8 (rated at 330 gross horsepower/300 net horsepower) and the 1973 and 1974 SD (Super Duty) 455 (CID) V8 (rated at 310 and 290 net horsepower respectively). As an example in 1973, Hot Rod Magazine test drove a factory stock SD 455 powered 1973 Trans Am and obtained a 1/4 mile time of 13.54 seconds at 104.29 mph. This was faster than most of the high compression muscle car motors from the muscle car golden era. Pontiac seemed to be leading no matter what the odds were up until 1975. It seemed the new for 1975 EPA emissions mandates which choked the engines with a single catalytic converter, EGR valve, and a maze of new vacuum hoses under the hood had finally put Pontiac's back against the wall.

    Pontiac announced in late 1974 that a L78 400 CID V8 would only power the 1975 Trans Am. This seemed like good news since the competition's V8s were much smaller in displacement, but the 185 net horsepower rating of the L78 brought any muscle car fan back to the cold hard reality that things had changed drastically from the previous years. The good news was that the Trans Am by 1975 was skyrocketing in sales, even though the Trans Am was detuned it still was faster than it's competition. And the buying public was taking note of this fact and voting with their dollars. Trans Am sales were skyrocketing for a reason. Even as muscle cars had waned in popularity the Trans Am provided fantastic handling and good performance all wrapped up in a stylish muscular shape. The 1975 Trans Am was a carry over from the successful 1974 Trans Am restyling. The only real changes in styling for 1975 were the front parking lights (which moved to the front grilles) and a new wrap-around rear window.

    Diehard Pontiac fans were still clamoring for more cubic inches, especially since Pontiac still made the Pontiac 455 V8, which was an option on the bigger Pontiac B-body, G-body, and A-body cars. Pontiac finally saw the error of their ways after the 1975 model year had started and decided to offer the L75 455 CID V8 from the bigger Pontiacs, which was rated at 200 horsepower. The good news was when the L75 was ordered the following were manditory: a limited slip 3.23 rear axle, a Borg Warner Super-T10 4-speed manual transmission, dual chrome twin splitter exhaust outlets, and front sintered metallic brake pads. All of these items with the exception of the Super-T10 could not be ordered on any other '75 Trans Am or Firebird. Since the L75 455 had come out of the bigger Pontiacs it came as no surprise that it produced plenty of low-end torque, 330 lbs/ft of torque at a very low 2,000 rpm. However due to the restrictive heads and a grandma type cam, the compression ratio was a very low 7.5:1. This meant a L75 Trans Am ran its best on 87 octane gas and began to run out of steam once it went beyond 3,500 rpm. Even with the L75 engine being a very low compression motor choked of power, performance was very good for 1975. Car and Driver Magazine obtained a 16.1 second 1/4 mile time at 88.8 mph which was almost a full second faster than the '75 Trans Am L78 400 which took 16.8 seconds to make the same run. The 0-60 mph time of the '75 L75 Trans Am was 7.8 seconds, which happened to be a full 2 seconds faster than the '75 L78 400 powered Trans Am. Even though the L75's performance figures paled in comparison to the figures of the previous years, The L75 Trans Am still beat the competition in performance. Even the lighter weight (than the Trans Am) 1975 Corvette could only obtain a 16.4 second 1/4 mile time and a 9.6 0-60 mph time making the Trans Am L75 the king of the streets for 1975. And if that was not enough for L75 Trans Am buyers back in 1975, it was very easy and cheap to almost double the horsepower with a few engine upgrades and bolt on parts, since what you had was a choked D-port 455 just begging for a hot cam, high performance heads, exhaust headers, etc.

    The 1975 L75 455 Trans Am was a wise move by Pontiac since it kept the Trans Am on top as performance king. This trend continued until the end of the 1979 model year when the last W72 400 powered Trans Ams left the assembly line. The mistake Pontiac made with the '75 L75 Trans Am was marketing the package as the 455 H.O. All L75 equipped Trans Ams received the "455 H.O." decals on the shaker hood scoop, which allowed critics to take a cheap swipe at Pontiac. And rightly so, since the '75 L75 Trans Am was at least 2 seconds slower in the 1/4 mile than the 1971 to 1972 Trans Am 455 H.O. The L75 option carried over to the '76 Trans Am with the same mandatory limited slip 3.23 rear axle and 4-speed transmission. Pontiac did learn their lesson by 1976, the package had just a "455" decal on the shaker hood scoop.

    For 1975 only 847 L75 455 Trans Ams were produced mostly due to the late 1975 model year introduction. By 1976 the L75 Trans Am option was much more popular with sales going over 7,500 units. The 1975 Trans Am L75 455 kept the Trans Am on top in terms of performance for 1975 and kept the momentum going. And things kept getting better for the Trans Am as the 1970s progressed. For that alone the 1975 Trans Am L75 455 deserves its recognition in the annuals of muscle car history. So in the final analysis the King did return after-all in 1975.



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    Vulture of The Western World Eric's Avatar
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    Re: 1975 Trans Am (L75) 455 H.O. - The King Returns?

    Wonderful stuff, Pete - thanks!

    These cars are going to be very collectible in years to come; if you find one, snap it up. I would!

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    Re: 1975 Trans Am (L75) 455 H.O. - The King Returns?

    Thanks.

    I have not seen in recent years a good conditioned one for sale. Saw a project '75 T/A L75 go up for sale a few years ago on ebay. There was a guy who posted on one of the Trans Am boards a few years ago that had a complete matching numbers one, it was sitting in his barn for 15 years. He was going to cut it up and turn it into a street rod, until we on the board told him how rare it was. He then started to restore it, by keeping it 100% stock. I don't know what happened to the guy, or if he completed the restoration. I hope he did.

    Here's a L78 400 Trans Am that's currently for sale on ebay, it's a car a guy rescued from the crusher and restored (don't see too many '75 L78s go up for sale as compared with the '74s and '76s):

    http://cgi.ebay.com/ebaymotors/Ponti...98015263QQrdZ1

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    Vulture of The Western World Eric's Avatar
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    Re: 1975 Trans Am (L75) 455 H.O. - The King Returns?

    Checked it out; I think he's asking way too much ($12k) for a "driver" 400/auto car that has a "salvage" title - and probably still needs a good bit of work, despite the ad's claims.

    A new carb, radiator, etc. - relatively inexpensive. Rusted pans and quarters aren't!

    I think $12k is a fair price to pay for a near-perfect '75 400/auto car - with a good title.

    I might pay $6,000 for this one - but have to examine it in the flesh to decide one way or the other...

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    Re: 1975 Trans Am (L75) 455 H.O. - The King Returns?

    Eric,

    I agree this car is not what I consider good condition, its more of a nice driver. I personally would not pay more than $6,000 - $7000 for it, reading this description. The guy only mentions a repaint of the body, so more than likely the bottom has got rust. Little things such as the missing air intake hose, does not have the dual twin spliter exhaust tips, etc. And the wheels are also non-stock they're those 15x8" stretched Rally IIs. If the car is rust free (including rust free on the underbelly) and the motor & transmission are matching numbers along with the q-jet being the correct #, I would pay $10,000 or more for it and then fix the little things I mentioned (if it was not a salvage title). The salvage title certainly brings the value down a little. I have a feeling since the owner did not mention this, that the engine is more than likely not matching numbers and the carb is probably not the right number/code. Especially since it sounds like the guys son can't drive sanely with it, it's probably got a hopped up 400 in it.

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    Vulture of The Western World Eric's Avatar
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    Re: 1975 Trans Am (L75) 455 H.O. - The King Returns?

    Yep!

    I'd hold out for a 4-speed 400 car at the least.

    You can still find these ('75-'76) for around $12k in very nice shape.

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    Re: 1975 Trans Am (L75) 455 H.O. - The King Returns?

    Eric,

    I agree the '75 L78 4-speed is a preferable to the automatic. Even though I liked the '74-'75 design, the '76 looked so much better. So if I was looking for a mid '70s Trans Am, I'd have to go with a '76 Trans Am. The '76 T/As had better quadrajet carbs than the '75s. The '76 quadrajets had the newer much improved APT (Adjustable Part Throttle).


    1976 Trans Am (LE - 50th Anniversary Edition):


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    Re: 1975 Trans Am (L75) 455 H.O. - The King Returns?

    Hi Pete,

    Yup!

    Did you know, by the way, that I used to own a '76 LE? No t-tops, but a 4-speed, 455 car. It was not perfect - but it was a nice "driver" that I bought circa 1990. A guy in a shitty old van ran a light in DC - and T-boned the car. It was totaled. I still have the shaker, though. And as it turned out, I was in a position to buy my current TA as a result. Though it's not a manual car, I still love it. (And I have thought about converting it to a 4-speed ... or even a five-speed... since I have no plans to ever sell it and it would make the car more enjoyable to me, etc.

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    Re: 1975 Trans Am (L75) 455 H.O. - The King Returns?

    Eric,

    I remember you showing me some of the leftover pieces of your '76 LE T/A a few years back. Even though you lost a great Trans Am, I think you ended up with a better one. The '76 carousel red Trans Am in my opinion is a better looking car than the 50th LE. It's the best Pontiac exterior color that was ever produced in my opinion. Only mistake Pontiac made was only offering the color for only two Trans Am model years - '76 and '80.

    Nothing wrong with an automatic on a muscle car. However if you do want to shift the gears manually I would go with an aftermarket 5-speed manual if you do highway driving with your car, if not the BW super T-10 4-speed should do fine.

    Check out this link of Rocky Rotella's 5-speed '76 T/A (he writes in High Performance Pontiac Magazine and he also posts on PY and TAC forums from time to time), he did the conversion a couple of years ago which he wrote a HPP article about. He told me on the TAC board soon after he did the conversion how much fun his car was to drive after installing his Keisler PerfectFit 5-speed (its a Tremec 5-speed). He mentioned how smoothly it shifted and that it was so nice to be doing low rpms on the highway when he shifted into 5th gear. He's running 500 horsepower from a slightly overbored 455 (467):

    http://www.thedrivenman.com/ke/gm/gallery/camaro.html


    If you look closely at the picture in the link above, another nice thing about Rocky's 5-speed is that it still looks fairly stock (most observers would not pickup on it not being 100% stock). The hurst shifter and boot are stock only the knob is not factory stock but still looks like a period correct aftermarket black Hurst knob.


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    Vulture of The Western World Eric's Avatar
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    Re: 1975 Trans Am (L75) 455 H.O. - The King Returns?

    Rocky's car looks great; do you know whether it was an automatic model originally?

    FYI - I have a 2004R in my car right now; it runs just over 2,000 RPM at 65 mph, even with 3.90 gears!

    ..but I still miss having a clutch...

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    Re: 1975 Trans Am (L75) 455 H.O. - The King Returns?

    Eric,

    I did not realize you had a 200R4. That's a great setup for what you have. I remember you installed a TH400 a few years back, which is a tough tranny but with no overdrive gear and a 3.90 rear it is high on the RPM scale over 60 mph. The 200R4 gives you that overdrive gear and the're easy to find a good core and build up to handle lots of horsepower and torque.

    Rocky's '76 was a 455/4-speed combination. He has over the years built up his car and had fun with it. Everything is original on his car except transmission, the 15x8" Rally II's, and the 3.73 rear (I believe the 455 that has been modified is the original block). His car is exactly like yours where he keeps it looking stock, yet he's set it up for serious performance. He's also had the T/A for years, and does not plan to sell it anytime in the future.

    I'd say if you really miss the clutch, go ahead and get a manual transmission setup. The switchover is fairly easy and it won't hurt the value of your car, if you put in a '76 manual console and '76 chrome hurst shifter (so it keeps the interior looking like a stock '76 T/A.


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    Re: 1975 Trans Am (L75) 455 H.O. - The King Returns?

    Hi Pete,

    The 2004R works wonderfully. Really transforms the car. It also gets rubber on the 1-2 and the 2-3 upshifts!

    The console looks stone stock, too. I have a custom indicator plate that reads D 321 - only eagle-eyed experts know that's not original.

    It has a full manual valve body - so you can hold any gear as long as you like.

    Still, in an ideal (money no object) world, I would love to have the car professionally converted to a four or five-speed, with "correct" floorpans, console, etc.

    I may even end up doing that with Jason. Spending $25k on the car isn't all that unreasonable, when you stop to think that's about what you'd pay for a "modestly priced" family car...




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    Re: 1975 Trans Am (L75) 455 H.O. - The King Returns?

    I know that this may sound like an almost oxymoronic question, but how has the O/D improved the fuel efficiency of the 455? I bet it has made for much more comfortable highway cruising, at least. How many RPM's at 70?

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    Re: 1975 Trans Am (L75) 455 H.O. - The King Returns?

    Quote Originally Posted by swamprat
    I know that this may sound like an almost oxymoronic question, but how has the O/D improved the fuel efficiency of the 455? I bet it has made for much more comfortable highway cruising, at least. How many RPM's at 70?
    The mileage is amazingly good - given what it is. On the highway, in OD and just cruising (appx. 2,200 RPM at 65-70 mph) it can hit the high teens, which is as good or better than what it did with the original drivetrain - which had anywhere from 100-150 hp less and much less aggressive (2.41) rear gears.

    I'd drive it anywhere. It is as comfortable as a new car. (Just a lot louder!)

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    Re: 1975 Trans Am (L75) 455 H.O. - The King Returns?

    Eric,

    Even if you add to the Jason restoration the conversion to a 5-speed tranny and you spend $25,000 on your Trans Am, that still is money well spent. It is still cheaper than a new car like you said. And your '76 Trans Am will only continue to go up in value as the new car will drop in value. Putting money into a car that is going up in value is the way to go. And when you look at it from a hobby standpoint, once you drop the $25K you won't have to touch that car for another 30 years or more (besides regular maintainance). There's a lot of guys who will drop $50K on a new 2007 Corvette, 10 years from now the car will be $15K, and your Trans Am will be worth $50,000 or more. So I would say you can't go wrong.

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    Re: 1975 Trans Am (L75) 455 H.O. - The King Returns?

    Quote Originally Posted by Disco Man
    Eric,

    Even if you add to the Jason restoration the conversion to a 5-speed tranny and you spend $25,000 on your Trans Am, that still is money well spent. It is still cheaper than a new car like you said. And your '76 Trans Am will only continue to go up in value as the new car will drop in value. Putting money into a car that is going up in value is the way to go. And when you look at it from a hobby standpoint, once you drop the $25K you won't have to touch that car for another 30 years or more (besides regular maintainance). There's a lot of guys who will drop $50K on a new 2007 Corvette, 10 years from now the car will be $15K, and your Trans Am will be worth $50,000 or more. So I would say you can't go wrong.
    Yep - it's good to rationalize our hobby, eh?




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    Re: 1975 Trans Am (L75) 455 H.O. - The King Returns?

    LOL ;D Remember what Jack called the hobby? Mad Car Disease...

    Actually truth be known even if our cars were only worth the value of a '70 Pinto, I would still dump money into a 2nd generation Trans Am, they are such fun cars to drive and own.

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