WARNING - if you are squeamish in the least, avoid this post, because it is not going to be pretty, nor is it going to be delicate.
OK, you know you have a vacuum leak toward the base of one of your carbs, Have you fixed that?
Which would cause excessive heat 'after a few accelerations', wouldn't it?

SM, are you aware we've been asking about this known vacuum leak for almost 90 days, yet Robert is still dancing his wee dance?
You are bandaging the problem, not curing it.
DING, DING, DING! Ladies and gentlemen, we have a winner!!

But, but, wait. He did say that 'cure' came from a 'master race car mechanic', didn't he? You're not actually suggesting that 'master race car mechanic' might equate to jackleg, are you? Oh. Wait. That was me making that suggestion, wasn't it?
You still have a problem somewhere.
<GASP> You mean crutching a thermostat with a bunch of holes didn't really fix anything?

You mean, <SPUTTER>, the problem still exists?
Even a extremely healthy, dual carbed hotrod motor could and should run 160-180 all day long....in stop and go traffic maybe creep up to 200, maybe 205.
Could, should, or the one that really cuts to the chase and stings the most - would.
Is your timing correct? Is your TDC marker correct? Have you fixed the Vacuum leak? Are you running too lean? Are you running the correct range of spark plugs? Is combustion gasses getting into the cooling system, ie, head gasket sealing problem? Have you run a compression check? All these things will give you some valuable info....you have a mystery, search for the answers, they are there, just gotta know what to look for....
Why bother with all of that stuff, when the problem gets <COUGH> 'fixed' with a hacked thermostat? And you know, you are wasting your time and a lot of ones and zeroes, by asking all those questions, because Robert has left a trail of unanswered questions (most of them being the same ones you just asked), over the last 3 months.
What most people will not stop to consider is when a racer uses water restricters, rather than thermostats, as
@baddawgcustoms mentioned, that is done to eliminate the possibility of a stuck thermostat getting between the race car and a possible winner's circle. Who runs fuses on a race car? But would you run a street car without the protection of fuses? Who runs a fuel filter on a race car? But would you run a street car without the protection of a fuel filter? Sure, there are tons of places where race technology can be applied to a street driver, but crutching an overheating problem with a butchered thermostat just isn't one of those places.
...and no, I only got so much time in a day as I still work for a living..
Hold the farging phone! Time to make sure everybody sees this horse exhaust for exactly what it is.
Sorry,
@Robert, I hear what you're saying about having to work for a living and your time being short, but here's the reality of the matter. Your known vacuum leak is likely the cause of your overheating, but it could also be causing myriad, other problems, as well. But you don't have time to investigate that possibility, aye? Yet you do have time to change thermostats twice, then pull the third thermostat to drill some holes in it, then pull the third thermostat a second time, to drill even more holes in it?

Nope, you don't have time to fix a problem that is right in front of you, but you have time to post here about everything, which doesn't mention that you also had time to engage a 'master race car mechanic' with the same issues? Did you bother to mention your possible vacuum leak to this 'master race car mechanic'? My money is all going on No, because if you had mentioned it, any mechanic in the world, 'master race car mechanic' or not, would have immediately had visions of burning valves and lifting ring lands in his mind, rather than hacking up a thermostat.
So tell me - you have had all this time to do all these things, but you do not have time to actually eliminate a glaring problem. Does that mean you will also have time to rebuild that engine, if it does lift a ring land, if it does burn a piston, if it does burn a valve? Because if that engine were properly tuned, had a high-flow water pump, a clean four-core radiator, the addition of water wetter, and a properly designed shroud around an adequate electric fan, you wouldn't be having any over-heating problems.
You're about to get all riled up at me, because I am going to say what everyone else has been thinking, all along.
Fix your known problems, before you start any more threads and before you hang any more band-aids on anything. Remember, band-aids don't fix anything, they only cover up the cuts and scrapes. You started
this thread, over 90 days ago. A total of 66 posts later, and you were still dancing around the questions people were putting to you. Instead of remaining involved in that thread, you started
this thread, some three weeks later. Within a few hours,
@TriodeLuvr rightfully pointed out there were unanswered questions in your first thread. Eight days later, you were back with
this thread, which you also abandoned after 30 posts, leaving even more unanswered questions. Six days later, you then had to start
this thread. Followed, just four days later, with
this thread. Two days after that, here you came with
this thread, where you ignored questions that were put to you, yet again. That same day, you started
this thread, because your knickers were knotted over getting called out for a rules violation. Nearly one month later, here you came again, with
this thread. And now, here you are, back again, with the same-old, same-old. We're approaching a total of ten threads, all addressing the same problem you identified almost 3 months ago. WTF?!? Then you have the sand to suggest you don't have time to do the things people have asked you to do, so we could all diagnose
your problem?
Most of the rest of us work for a living, but isn't it interesting how you keep coming to us, to have us try to divine your problems for you? Everyone else seems to be missing this finer point, but I caught onto your game within your first handful of posts. Your time is valuable, too damn valuable to spend fixing your own stuff, but it is perfectly acceptable for you to waste our time??? You can't be bothered to use a bit of common sense, but you can bleed off our free time? You can spend time picking everyone's brain, but you don't have time to answer questions asking for more details. WTF makes your time any more valuable than anyone else's time?
You, sir, have become a Help Vampire. You are sucking help from the kind-hearted members of this forum, who have tried, time and again, to help you with your problem. But instead of listening to what people are asking and then providing complete answers to those questions, you simply ignore the help you've been provided and run off to start another thread, to suck more help. And you know what? That ends, right here and right now.
Get your own ducks in a row. Search the site for answers, before you ask any more questions. If you cannot add enough details to allow others to fully understand your problem, then don't ask the questions, because we all know you are never going to come back and provide any requested details. Do not offend our intelligence by suggesting you do not have time to research your own problems, when a blind man can clearly see you've spun your wheels for over 90 days. If you can't be bothered to diagnose anything, then stop assuming we have the time to hold your hand. If someone asks you for more details, get busy providing those details, because none of us here can read minds.
If you cannot follow these instructions, then you are clearly in the wrong place. Which is as politely as I can think to say that either you tune up your act, or you are going to find yourself out in the alley. Understood? You've worn out my patience with this ongoing nonsense, and in the so-doing, you've worn out your own welcome. Get yourself in order, before you post anything to this site again, or I will toss you out before you know it. Doubt what I am saying? Then go right ahead and push that line. You are at the end of the line, so choose your way forward, very, very carefully.
If you want to waste someone's time with this B.S. of yours, then waste your master race car mechanic's time. If you want some real help, then drag your sorry backside back into those other threads and start answering the questions people have put to you. And then try showing a tiny bit of flippin' gratitude for those same people taking the time to deal with the things you have no time to deal with on your own.
As for myself, I am off to the library, to learn what qualifications are necessary to become a 'master race car mechanic'.

Screw me to tears, that one may not be the wildest one I've ever heard, but it certainly ranks right up there.