Soldato
- Joined
- 26 Aug 2003
- Posts
- 24,275
This is the coolest car out of all the ones you've had I think, and you've had some pretty cool cars.
The life and times of UPO 69, my 1968 Pontiac Firebird.
- Thread starter Lashout_UK
- Start date
This one is a 'built' TH400 three-speed automatic. Practically indestructible and ideal for dealing with the high levels of torque.
It is just a conventional automatic, although this one has a high-stall torque convertor. Basically imagine slipping the clutch for a little longer to allow the revs to rise more when moving off and you've got how it works. It allows the engine to really get going and helps avoid it bogging down. A transmission cooler integrated into the radiator stops the fluid from overheating.
Mine shifts faster and firmer thanks to a modified valve body too. Nothing overly aggressive though, it's a street car after all.
Topping it all off is a Hurst shifter. The action differs somewhat from a conventional shifter. To go from park to neutral you have to pull up on the trigger assembly and pull the stick to reverse. To engage neutral you have to then push the stick down, into the floor, and pull it back. At this point it then functions like a normal shifter and you can move up and down through the gears as you desire.
For racing, however, it offers a ratchet mode. In neutral, push down on the stick and pull it back into drive and down to 1st. This engages the ratchet mode which allows you to bang through the gears, with a single push engaging the next gear, and stops you missing any shifts - i.e. going from 1st to drive by mistake.
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A friend is into his Camaros, and mentioned sometimes the best way into ownership of one is to buy someone elses project, which by the sounds of it you roughly did, and got the pricey upgrades for little outlay, but knew you'd need lots of finishing time to make the rest come together.
Still dreaming of a a similar era truck Apache/S10 etc etc here
Look forward to hearing how this goes for you. Few more photos of the interior?
That's what I thought at the time. I really wanted to build something up but it's so much cheaper if you let someone else spend all the money then pick it up as a going concern afterwards. Obviously it varies depending on the car you're looking at but it was certainly the case here.
Admittedly I'd still like to build a car from the ground up but when things like this cost quite a lot anyway, and high-end performance parts aren't cheap, I realistically didn't have the budget for it - nor the inclination to spend that much. Then you have to consider the time and space aspects of working on a long-term project like that. This was, at that point, the best choice for me.
I'm not a great fan of things you can't actually use either, so wasn't keen on ending up with something that was going to need a vast amount of work to simply get it driveable.
This is the interior, not long after I got it in September last year. Still needs some tidying up but it's all there and I have the missing bits of trim.
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Soldato
That is just amazing. I really want to own an authentic American muscle car one day, and ideally just like you get it with working needed so I can properly get to know the car as I get it up to spec!
*sigh* one day!
*sigh* one day!
Soldato
That is quite simply epic 
Cheers
When I bought it there were three major problems that needed sorting:
- The rear differential, despite being new, made a horrendous groan when you lifted off the throttle. It also leaked.
- It ran but not very well. It was also hilariously rich, so much so that your eyes would sting at some points due to unburnt fuel and fuel being blown back out of the carburettor.
- There was an oil leak from the rear main seal on the engine, which left a few minor drops on the drive.
The rear differential was easily fixed. I got it rebuilt by the local specialist, who found that the inner bearings had been hammered in. This had damaged the load-bearing surfaces, leading to the noise. You could see the imprints of each roller on the surface, so they must have clobbered it pretty hard. A new rear seal stopped the leak.
Originally the Firebird would have had, I think, a 10-bolt axle. Mine came with a stronger 12-bolt rear axle fitted with custom axle shafts, upgraded fixings and retainers and an Eaton Posi limited slip differential. Should withstand the power without any problem at all, as it's claimed to be good for upwards of 600BHP.
Back after its first trip to the workshop:
Getting it running properly was a little more involved. With nothing known about the engine build the cam timing and ignition timing was checked and found to be fine.
I didn't know what the compression ratio was but I had the feeling that it was probably quite high and as a result the spark was struggling. An MSD Streetfire ignition system was installed, boosting the spark strength and also adding a limiter. This helped but the fuelling was still all over the place.
So, a new Edelbrock carburettor was bolted on in place of the old Barry Grant unit. It's vastly improved things and the car now starts and runs very easily. With a rated flow of 600cfm it's probably not big enough but it lets me get used to the car and avoids any lean situations or bore wash. It'll be replaced in the future with either fuel injection or a larger carb, once things have settled down.
Before:
After:
The oil leak I was prepared to put up with. Although I like my cars to be dry underneath, changing it out meant dropping off the sump and removing the rear main cap. Because it only dropped a few small spots from time to time, it wasn't a real issue.
Some weeks later, after some spirited driving, the cabin promptly filled with blue smoke. D'oh. The drip of oil was now a deluge and it was pouring straight onto the headers. I relented at this point and drove it straight to the workshop.
I'd previously ordered an upgraded rear seal, made from modern materials, along with some more oil and a new modern sump gasket which would hopefully fix the problem and mean I'd never have to think about it again.
With the car handed over to my mechanic, who has proper lifts and a dry environment to work on the car, he set about sorting it out. He rang me up a few days later to tell me that the engine already had the modern seal installed. A moment of panic ensued, as I wondered what had failed. Had the block cracked? He put my mind at rest almost instantly. Whoever had worked on it previously had installed the aftermarket seal...
... but they'd fitted it back to front. Didn't make a very good seal, as a result.
The exhaust manifold was also "modified" at this point as previously it'd been touching the steering gear.
I've done quite a lot to it so far as well. I've rebuilt the rear light clusters, removed a cheapo rear amplifier, subwoofer and speakers, sorted a lot of the wiring, replaced all four headlamps, repaired the indicator stalk, adjusted the tracking, installed a fuel filter, fitted some new detail parts, properly fitted the door glass and fixed the mechanisms, repainted the boot, installed a PCV system, fitted an extinguisher, freed off the heater controls, fixed the door handles and things like that.
Still plenty to do mind, but mostly just odd jobs to tick along with as and when I get the time.
Tempted to nickname it Snowbird - these were the conditions that I took it out for its first proper drive in:
When I bought it there were three major problems that needed sorting:
- The rear differential, despite being new, made a horrendous groan when you lifted off the throttle. It also leaked.
- It ran but not very well. It was also hilariously rich, so much so that your eyes would sting at some points due to unburnt fuel and fuel being blown back out of the carburettor.
- There was an oil leak from the rear main seal on the engine, which left a few minor drops on the drive.
The rear differential was easily fixed. I got it rebuilt by the local specialist, who found that the inner bearings had been hammered in. This had damaged the load-bearing surfaces, leading to the noise. You could see the imprints of each roller on the surface, so they must have clobbered it pretty hard. A new rear seal stopped the leak.
Originally the Firebird would have had, I think, a 10-bolt axle. Mine came with a stronger 12-bolt rear axle fitted with custom axle shafts, upgraded fixings and retainers and an Eaton Posi limited slip differential. Should withstand the power without any problem at all, as it's claimed to be good for upwards of 600BHP.
Back after its first trip to the workshop:
Getting it running properly was a little more involved. With nothing known about the engine build the cam timing and ignition timing was checked and found to be fine.
I didn't know what the compression ratio was but I had the feeling that it was probably quite high and as a result the spark was struggling. An MSD Streetfire ignition system was installed, boosting the spark strength and also adding a limiter. This helped but the fuelling was still all over the place.
So, a new Edelbrock carburettor was bolted on in place of the old Barry Grant unit. It's vastly improved things and the car now starts and runs very easily. With a rated flow of 600cfm it's probably not big enough but it lets me get used to the car and avoids any lean situations or bore wash. It'll be replaced in the future with either fuel injection or a larger carb, once things have settled down.
Before:
After:
The oil leak I was prepared to put up with. Although I like my cars to be dry underneath, changing it out meant dropping off the sump and removing the rear main cap. Because it only dropped a few small spots from time to time, it wasn't a real issue.
Some weeks later, after some spirited driving, the cabin promptly filled with blue smoke. D'oh. The drip of oil was now a deluge and it was pouring straight onto the headers. I relented at this point and drove it straight to the workshop.
I'd previously ordered an upgraded rear seal, made from modern materials, along with some more oil and a new modern sump gasket which would hopefully fix the problem and mean I'd never have to think about it again.
With the car handed over to my mechanic, who has proper lifts and a dry environment to work on the car, he set about sorting it out. He rang me up a few days later to tell me that the engine already had the modern seal installed. A moment of panic ensued, as I wondered what had failed. Had the block cracked? He put my mind at rest almost instantly. Whoever had worked on it previously had installed the aftermarket seal...
... but they'd fitted it back to front. Didn't make a very good seal, as a result.
The exhaust manifold was also "modified" at this point as previously it'd been touching the steering gear.
I've done quite a lot to it so far as well. I've rebuilt the rear light clusters, removed a cheapo rear amplifier, subwoofer and speakers, sorted a lot of the wiring, replaced all four headlamps, repaired the indicator stalk, adjusted the tracking, installed a fuel filter, fitted some new detail parts, properly fitted the door glass and fixed the mechanisms, repainted the boot, installed a PCV system, fitted an extinguisher, freed off the heater controls, fixed the door handles and things like that.
Still plenty to do mind, but mostly just odd jobs to tick along with as and when I get the time.
Tempted to nickname it Snowbird - these were the conditions that I took it out for its first proper drive in:
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These are the next things to fit:
An OEM front spoiler to help improve stability and a rear strut brace to strengthen the rear suspension. I'm not sold on the front spoiler yet, will have to mock it up to see what it looks like.
The engine in the Pontiac is solid mounted to prevent it breaking free from its mounts and to improve chassis rigidity. Fitting the brace should help further strengthen the shell and I'd like to think that it'll have a few handling benefits as well, but we'll see.
Also managed to track down a picture of the car when it was being originally built up. It's come a long way.
An OEM front spoiler to help improve stability and a rear strut brace to strengthen the rear suspension. I'm not sold on the front spoiler yet, will have to mock it up to see what it looks like.
The engine in the Pontiac is solid mounted to prevent it breaking free from its mounts and to improve chassis rigidity. Fitting the brace should help further strengthen the shell and I'd like to think that it'll have a few handling benefits as well, but we'll see.
Also managed to track down a picture of the car when it was being originally built up. It's come a long way.
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Caporegime
solid engine mounts? as in totally solid or polyurethane? i bet you can feel that at idle..
Totally solid. It's not as noticeable as you'd expect, you know. The engine's quite smooth but there is a bit of a buzz and vibration at idle. On the move it's OK.
You can feel it when you stamp on the throttle though, damned thing tries to lift its nearside front wheel off the ground.
I did wonder what negative effects, if any, a solid mounted motor may have on a car's structure and powertrain. The general consensus, however, seems to be that you'll get a little more vibration and that's about it.
Asked my mechanic about it and his response was "Well, at least you know it's not going to go anywhere."
I was initially concerned that fitting the rear strut brace could have an adverse affect by causing the twisting force through the shell to move somewhere undesirable or weak but I don't think that's going to be an issue, although any input is appreciated.
You can feel it when you stamp on the throttle though, damned thing tries to lift its nearside front wheel off the ground.
I did wonder what negative effects, if any, a solid mounted motor may have on a car's structure and powertrain. The general consensus, however, seems to be that you'll get a little more vibration and that's about it.
Asked my mechanic about it and his response was "Well, at least you know it's not going to go anywhere."
I was initially concerned that fitting the rear strut brace could have an adverse affect by causing the twisting force through the shell to move somewhere undesirable or weak but I don't think that's going to be an issue, although any input is appreciated.
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Associate
Awesome car, would love to own something similar one day.
Associate
- Joined
- 6 Jul 2008
- Posts
- 1,841
How does changing the alternator bring 30hp?
It's still running off the same belt presumably....I'm not being antagonistic, I am genuinely interested.
It's still running off the same belt presumably....I'm not being antagonistic, I am genuinely interested.
Associate
I don't think he was being serious 
Associate
- Joined
- 6 Jul 2008
- Posts
- 1,841
I don't think he was being serious
Yeah....woops.
Everyone knows that if you chrome something it adds power, right?
The alternator is an uprated item, like pretty much everything else on the car, but it's not that good.
I know why I'm loving this one so much now, because I'm not into my yanks all that much. When I was a small kid my dad had a '68 Pontiac Tempest. I forget what the differences were between the Firebird, Tempest and GTO, but it was the same Coke bottle shape and the same shape at the front. I remember the rear windows that rolled down like the GTO in Bullitt
His was in a dark heavy metallic green, running a full steel flipfront, Chevy 383, tunnel ram, twin double-pumpers, ridiculously high stall converter that used to make it impossible in traffic and it used to run 11's at Santa Pod in the early 80's, where we used to spend most weekends. Oh, and I remember it used to overheat quite a lot
His was in a dark heavy metallic green, running a full steel flipfront, Chevy 383, tunnel ram, twin double-pumpers, ridiculously high stall converter that used to make it impossible in traffic
and it used to run 11's at Santa Pod in the early 80's, where we used to spend most weekends. Oh, and I remember it used to overheat quite a lot 
Awesome I think I'd like something powerful, old and Yank, this is my mechanics GTO Judge he's had it years and just keeps adding to it
http://www.twobeds.com/upload/userfiles/maccapacca/003.jpg
http://www.twobeds.com/upload/userfiles/maccapacca/004.jpg
http://www.twobeds.com/upload/userfiles/maccapacca/005.jpg
http://www.twobeds.com/upload/userfiles/maccapacca/003.jpg
http://www.twobeds.com/upload/userfiles/maccapacca/004.jpg
http://www.twobeds.com/upload/userfiles/maccapacca/005.jpg