[Tygrr67]

Hey all... I just picked up this 1966 Grand Prix, please note the before and after pictures listed below. The odometer is listed as 38,000 and because of the condition and history of the car I am inclined to believe it might be accurate. One thing that bugs me though is the exhaust. Does anyone have any pictures of a 1966 Grand Prix with the factory exhaust tips? Did they get the trumpets like a 1966 GTO? Were there even any factory exhaust tips?..

any insight is greatly appreciated... thanks in advance...

[Tygrr67]

And here it is after getting the clean up..

[Old Goat 67]

DAMN......

Those exhaust ahead of the rear wheel are NOT factory.

[Jeff Hamlin]

Duel exhaust was an option,
but don't see tail pipe extensions listed in the '66 accessories list for B-Body.

And yes those side pipes have to go

[hurryinhoosier62]

Nice GP!

[marxjunk]

why do they have to go? if i liked them..id keep them...

they has either resonators or not and they turned down at the bumper..no trumpets..but, if you want them do it..i like the trumpets

[bigger=better]

NOICE!

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[Tygrr67]

So, after some more clean up and review, I am now certain that this is not a 38,000 mile car but most likely a 138,000 mile car. There is some paint over-spray on certain areas and paint peeling in others. Regardless, the car is damn solid and doesn't appear to have any rust issues other than the expected surface rust in areas. I don't think it's been in any major accidents, but a thorough cleaning reveals the mystery. Things that it needs are a head liner, new wood veneer, chrome trim for tail panel (please text me if you have them 701.509.0786), new fuel pump, carb kit, speakers, belts, hoses, and most likely a brake job. After dropping the gas tank and dumping the rusty dirty fuel, I took said gas tank to the local car wash and power washed it out. The fuel sending unit is bad also, but I put it back together and and now have about 30 miles on it. Thumbs up everywhere except the wife who thinks it's too loud... At this point I have decided to simply clean up the engine bay, replace some of the aforementioned items and replace the exhaust to appease the powers of persuasion . Right now though it runs really nice and the weather is cooperating. I'm debating about running this to Iola Old Car Show for the car show in July. I know I'm going.... just not certain I'll take the car...yet.

[OZZIEVILLE 67 2 door]

Great looking old car
Thanks for story and pics
John L.

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[SIX8YAK]

Love to see the big Ponchos out and running. Great pickup.

[Ragtop Man]

Only question marks for a road trip (assuming new fluids, belts, hoses, etc) would be the cooling system and whether or not it would make the round trip in the summer.

Also, what is the compression in each of the cylinders - as long as you don't have head gasket issues, I'll bet you could make the R/T.

[Tygrr67]

So... driving it has produced a few more bugs. I must need to clean the gas tank a little more because it plugged up a filter after the about 10 gallons of fuel used. Replacing the fuel filter was an easy fix and I located a clear plastic one to keep on eye on it. More importantly I bought an extra one and tossed it into the glove box with the screw driver necessary to perform emergency roadside assistance the next time the motor starts to starve for fuel.

Another snag was the complete and total loss of brakes while pulling into my driveway (thank God actually...). For some reason the brake master cylinder took a crap and died. Believe it or not our local O'Reilly's had one in stock... so, 30 minutes, 3 bolts, and a bench bleed later I was back on the road.

Does anyone have an recommendations regarding the exhaust manifolds. I have a spare set of aftermarket 67 GTO HO manifolds that I thought might be a cool add on. But after thinking about it...I want this to look as 1966 period correct as possible. With that in mind, I have been thinking about buying a set of the 421SD long branch and then doing my exhaust job. Given that this is a 389.... Is it really worth the effort and extra money or should I use the factory ones in place? What about adding the X-pipe? If the car only sees DQ trips and car shows (3000 miles a year), am I wasting my money?

[Stuart]

The SD manifolds aren't period correct either - they were only used on the SD cars in 1962 and 1963. If it's mainly a fun cruiser to take to the Dairy Queen, save your money and leave the exhaust manifolds as is. Unless you're doing other horsepower modifications to the engine, all those changes to the exhaust system aren't going to gain you very much.

[Old Goat 67]

I arrived at the same decision 10 years ago.

[MUSLCAH]

Nice ride.....my wish list ...is one with a factory 4 speed

[marxjunk]

"I have a spare set of aftermarket 67 GTO HO manifolds that I thought might be a cool add on"


wont fit these cars..one is center dump other is rear...you need long branches for a big car or firebird...so it will clear the obstacles..just buy the Pypes down pipes for the stock maifolds to 2 1/2..and put nice mufflers on it and enjoy it..3 or 4% increase with long branches isnt enough to justify the cost..

[Heybuck]

Don't forget if you fit the 421HO long branch manifolds, you are going to have get the bracket adaptor which relocates the oil filter.

I'd be leaving it stock exhaust. Someone who was pretty smart back about 1964 when they were designing these cars, worked out what was a suitable exhaust manifold for your car. Can't really see why anyone would want to change it today.

Ian

[Tygrr67]

I've got to do something with the exhaust. As it is, running straight out the side, either ole' smokey will harass me first or the wife will leave, it's just that annoying. I guess my logic is trying to get a little more zip from it with a stock appearance. I didn't realize the oil filter would need relocated or that it would be that much of a hassle. I just want it to look stock with the best performance I can get from the 389. While I do have a 421 block in reserve, this is a numbers matching car and I intend to leave it that way. So........ after everyone's input (and thank you BTW..) I will leave the factory exhaust manifolds and run the factory designed dual exhaust. I guess that makes the most cost effective sense.

This week's drive went about 100 miles round trip and the car has started running hot when at idle. I'm going to pull the radiator and have it flushed and I also have a new heater core on order. I figure I might as well get everything new (hoses, belts, heater core, etc...) Why tear it apart 3 times, right?

The Pontiac curse has also gone into effect and on a few occasions the engine has not started when it was hot. I'm going to try a radiator flush and flow cooler water pump replacement to see what happens. It only takes once to get stranded and then you begin to wish it has things like actual temperature gauge rather than the idiot light that likes to pop on/off. I might be in the market for a factory set of rally gauges and harness if someone doesn't want to rob my kid of their college tuition.

I think the last thing I want to mention is that I really enjoy driving this car. I've driven GTOs, firebirds, and other GM toys before; but I'm beginning to think people have really missed the boat on Pontiac big bodies. They float like a Cadillac and have the looks of a GTO. For such a big car the gas mileage could be a lot worse and the performance isn't all that bad either. This thing gets thumbs up everywhere (almost annoyingly so) and I have enough room in vehicle for one hell of a party. I'm 6'6", my brother is 6'4" and my father-in-law is 6'2". All three of us drove around for a bit yesterday and we easily could have picked up another basketball player and cooler of beer to really start some trouble. I'm certain the majority of people reading this segment of the forum have driven a big Pontiac, but if you're reading this and haven't, then you should.

[Heybuck]

Very good choice to go with the factory stock exhaust. You will find it creates enough "burble" to satisfy you and make the wife happy. So, a win-win situation there.

I agree with you pulling the radiator but unless you have concerns about the heater core, I'd be leaving it right where it is. Quite a messy job to pull it out (ask me how I know.....). I always carry a small U shaped 5/8" tube in my trunk along with some hose clamps. If the heater core ever started to leak, I can easily pull off the hoses under the hood and bypass the heater core.

Usually you can smell a weeping heater core when the corrosion inhibitor starts to drip out so you usually get plenty of warning of an impending problem. I've never seen a heater core suddenly blow out. Not saying it doesn't happen but I've never seen or heard of it.

[Stuart]

Some years ago I bought a low mile 1965 GP and it wanted to run hot - I got the radiator flushed and all was well after that.