April 1968 Mark III new owner introduction

[LithiumCobalt]

Ok, yes, I whole heartedly understand where the auto industry went and it was severely detrimental to just about everything performance, efficiency or drivability. I was more talking about the emissions systems in context of the Mark III. The setup was so simple. It must have contributed to better emissions otherwise they never would have equipped them that way. The real tax on horsepower has to be barely measureable. It’s why I don’t understand the first inclination is to gut the system. I like things mostly as they came from the factory, though, so maybe that’s just me.

The whole retardation of timing and all the limits put on things, blah, blah, I acknowledge was not a fun time for autos. We practically lost 20 years until technology finally caught up and things began to improve. All courtesy of the federal gubment.

[1Bad55Chevy]

I brought up the smog ports in the head because the OP said the vehicle does not have a smog pump on it. Just a heads up for something he should look out for!

[1Bad55Chevy]

I just bought a 69 mark III. 61,000 miles (or is it 161,000?) complete California/Arizona car. Build date 4/15/68, so it’s one of the oldest. Wheel covers are dated 4/10/68. White with white leather, black top. Starting to get to know her, new discoveries every day! I think I’ll call her my “Tinker Toy!”

http://automotivemileposts.com/contentsmark3.html

I found this article on the internet and found it interesting. Apparently they hit the show rooms in April of 1968 so there might be a few models out there date coded earlier.

[frasern]

The date on the data plate is inaccurate, a Marti report will provide a true date of production. Their web site explains this, but basically that date is predicted on the order, but any delays in component production affect the date of final production. My '67 was built 38 days after the date shown.

Back to the smog pump, my '71 heads have no holes, the heads were never machined for it, so no need to block it off. My '68 heads appear the same.

[1Bad55Chevy]

Your 1971 head D0VE head dosen't have this port on the front and back? This is the front of the block so it it capped with a freeze plug from the factory.

The heads are the same for either bank so the holes are present on both sides of the casting.

There are also "bumps" in the exhaust port for the EGR system as seen here. From reading on the internet these bumps were on everything to include the CJ and SCJ heads.

Exhaustpocket.jpeg (33.67 KiB) Viewed 152 times

[frasern]

Your picture is a little too close to see the exact position, but I think we're looking at the same spot.

Top is right rear, I didn't post these before, because the engine was sitting in a dirt floor shed until I built my shop, and I haven't cleaned it yet.

[1Bad55Chevy]

Thats the spot.

And that's a D0VE head? I know the C8VE or C9VE would be like yours. I also know the CJ/SCJ heads have that casting but without the hole. I have never seen a D0VE head without the hole, but I am still learning. Every time I think I really know some shit I get knocked on my ass!

[TonyC]

Nice article, though there are some omissions and errors in it. The most notable one is below.

Sales of the Mark III each year outpaced those of the Cadillac Fleetwood Eldorado, which was the Mark's main competitor, but no doubt also impacted the sales of its sister, the Thunderbird, to some degree.

Not true; the Mark III never outpaced the Eldorado...though in '71 it came very close: Falling behind overall by just a few hundred units; but if the Eldo 'verts were subtracted out, the Mark III outsold the Eldo coupes by over 6,000 units. The outpace wouldn't happen until '72 with the Mark IV.

Still, an enjoyable read.

---Tony