Author Topic: 77 and 78 differences??  (Read 7839 times)

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Offline femsxy3

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77 and 78 differences??
« on: January 20, 2007, 11:55:14 PM »
Hello,
I was wondering, what are the main differences of the 1977 and 1978 Trans Am (besides new paint color)??
I know the Gold Edition was offered in 78, but were there any other engine upgrades or body changes?
Or are they the same exact car?
Thanks
S

Offline milly

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77 and 78 differences??
« Reply #1 on: January 21, 2007, 02:50:45 AM »
The front grills are not the same. The shaker on the later '77's and the '78+ are different from the early '77's. The W72 400 is more powerfull in '78 than in '77. The WS6 option became available in '78.
John
1981 Trans Am
1996 Firebird

Central Illinois Firebirds
Ohio Firebirds

Offline LeighP

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77 and 78 differences??
« Reply #2 on: January 21, 2007, 09:19:32 AM »
As John mentioned, the grills have a cross-hatch pattern in 78 rather than the 77 honeycomb pattern. The tail lamp covers are painted low gloss black in 78 (I believe this actually started some time during the 78 model year). The interior trim on seats and doors are different. From memory, 78's have the power door lock switches on the doors...77's have it on the dash as do earlier cars. 78's had the option of factory Fisher T-tops.
Decals.....the TRANS AM font style changed in 78, most cars still used the earlier 73+ hoodbird - except solar gold cars got the new style bird.
There are probably some other small spec changes as well...but its 1:30am and I can't think of them now....lol.
Regards,
Leigh
1971 Pontiac Firebird 455

Offline John Witzke

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77 and 78 differences??
« Reply #3 on: January 21, 2007, 09:53:35 AM »
As mentioned grill chages, decal font style (no TRANS AM decal above driver side grill headlights) and black tail lamp bezels (actually started around the first week of Jan 1978), interior changes were made as well.  Door panel style changed for both standard trim and custom trim interiors.  Custom interior seat style changed.


W72 engine for 1978- Pontiac changed the part number in 1978 for the camshaft used in T/A 6.6 engines, so it has been rumored for many years that a change in duration and timing characteristics was made as well.  Recently, good friend and overall Pontiac performance expert Rocky Rotella, proved this rumor to be true.  Comparison between all three cams indicates the 1978/79 version has a few more degrees of intake duration with more aggressive intake lobe lift and gross intake valve lift using 1.50:1 rocker arm ratio than the 1977 cams.  It appears the changes in the camshaft profile would result in approx 10 hp increase over the 1977 W72 camshafts.  4-speed W72 cars cam with 3.42: rear gears.  There were other minor changes, such as air cleaner, vacuum hose routing, etc.  If you need that info in can go into depth.

Hope this helps,

John
John Witzke

Offline ta78w72

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77 and 78 differences??
« Reply #4 on: January 21, 2007, 01:01:15 PM »
Pluse wipers were available in 1978.

Offline Joker (§ir£Ğragon)

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77 and 78 differences??
« Reply #5 on: January 21, 2007, 01:48:53 PM »
15x8 Snowflakes became available in '78 along with the WS6 package.
Larry


Offline fb_rider

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77 and 78 differences??
« Reply #6 on: January 21, 2007, 08:51:17 PM »
I know the radio is different, and a lot easier to find on ebay, for the 78.  The power lock solenoid is different, as I had a hard time finding one for my 77 (Thank you Brett!).  Also, the power lock switch is different - it is a rocker switch on the dash next to the defog switch on the 77, and I think it's on the doors on the 78.  Of course, they also switched to the fisher t-tops sometime in 78.  And I'm pretty sure all of the 77's came with 15x7 snowflakes (which on the SE had red inserts vs gold on the 78).  Last thing I can think of is that the front emblem was red in 77 and gold in 78 on the SE's.
1977 Trans Am SE w/W72 engine (sold)
1999 Trans Am Anniversary Edition #953 (sold)
2000 Trans Am Firehawk #263

Offline fb_rider

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77 and 78 differences??
« Reply #7 on: January 21, 2007, 08:52:58 PM »
By the way, my 77 auto has a 3.42 rear.  Is it possible that this was a factory option?
1977 Trans Am SE w/W72 engine (sold)
1999 Trans Am Anniversary Edition #953 (sold)
2000 Trans Am Firehawk #263

Offline MalteseFalcon

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77 and 78 differences??
« Reply #8 on: January 22, 2007, 12:26:12 AM »
Dash is different over the radio - to accomodate the larger radio.
Steve

1978 WS6 W72 4 Speed - Martinique Blue on Light Blue - Fire Am restification Project
2000 WS6 6 Speed - Black on Ebony - Daily Driver