What Happened to you, Engine?

corroded rocker shafts
In an effort to simplify transmission options and have a broader torque curve, we’re upgrading from a 200ci straight six to a 250ci unit. The basic engineering’s the same, but the 250 has a longer stroke and uses the same bellhousing as small block V8. There’s not a lot of love for the 250; for the effort to swap it, you might as well drop in a V8.
I was able to pick up a pair of them for a few hundred bucks, giving me a spare or a power plant should we resurrect the Crunchero. We tore into both to figure out who’s the starter and who’s backup, and hoo boy, was that an easy decision. Check out the surfaces on this motor.
cylinder bore marks

 

18 Comments

  1. Back when I had a ’63 Falcon wagon with a 170, a buddy and I swapped in a 200. Then, a few months later that same buddy found a 250 head in the back of his garage, and figured that with its larger intake runner, would make a 200 breath better, so we spent a day swapping the 250 head and carb onto the 200.
    For all you Falcon Six tinkerers out there, don’t make the same mistake. The 250 head did NOT improve performance at all, quite the opposite. From what I remember, the 250 engines were much later, were hampered by a number of compromises for emissions compliance, but most importantly, served to reduce the effective compression ratio on my 200. The 200 head/carb went back on the following week.

    1. So, what I’m reading is that a 250 head will lower the compression on a 200 to allow for more boost.

    2. The big problem you had was drop in compression.
      The chambers on the 170 were tiny, but much bigger on the 250. Also, they stopped making the thinner headgaskets they were originally equipped with. You probably ended up with a low-7s CR.
      Now, if you mill 50-60-70 thousands off the block…that’s a different story.
      …then you might make triple digit horsepower!

  2. “Your engine’s flooded” meant something far worse than usual at some point in this motor’s career.

  3. Been sitting a long time…
    The 250 conversions are more common here in Australia where there are better options eg alloy crossflow cylinder heads, and are cheaper and more insurance-friendly.

  4. Looks like it was laying on its side for awhile.
    Many years ago I helped a friend tear down a Pontiac 428 in a ’69 Bonneville Safari (he bought the running-and-driving car for $200, just to get the block and the crank). We pulled off the intake and the valve covers, and the amount of sludge was incredible. The heads were were full and the rockers were caked with it (you could see trails on them, indicating the oil flow), and in the valley, the pushrods ran in grooves, the hardened-into-plastic sludge all the way up to the level of the pushrods. Needless to say, the main and rod bearings were very worn, and the cam bearings were shot. The oil pressure relief (bypass) valve was open, so that the oil was going around the filter.
    My friend wanted to blame it on Pennzoil, as the previous owner used that (my friend and I are strictly Valvoline users), but I figure it had as much to do with a lack of routine oil changes.

  5. Tim, I commented on an article you did back in 2011 on using your Falcon as a “daily driver”. It said you were doing a follow up to that article, but I never found a “part 2”. Was a follow up ever done? Thanks, Woody

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