The 270 was one of the early, and best, hot rod engines, pre-SBC!
There were lots folks “didnt worry about.”
not only Carl…I have a book entitled " How to hop up Chevrolet and GMC Engines",
accquired when I owned a '44 6 X 6 GMC CCKW353, very regretfully sold, was wishing I still had it recently to drag some big logs up a mountainside, mine was fitted with an extra heavy duty winch, also had many spares including an engine
Hi Tony,
I check in on the old stuff on occasion, Fronty Fords etc, and a number of years ago I ran across The12 Port Story, the story of the Wayne 12 port head, in it’s many variations, for Chevies and Jimmies. I just checked and it’s still on line, pretty interesting and there is still a considerable amount of interest in these old engines. I’ve only seen one Wayne head in my life, on 2nd thought maybe two as I seem to recall Peterson’s Museum in La had one, and that was at Zakiras, a shop on the out skirts of Cincinnati that at that time, probably 15 years ago, specialized in rebuilding, among other things, the the old Miller race cars and engines and they had a, maybe the only one, Miller 1300CI hydroplane engine that they were rebuilding. The crankcase was separate from the cylinder block/head and there were four newly cast block/heads along with the crank and the crankcase was on a jig and it was very obvious that it had been “ventilated" and patched several times. Some years later I saw that the engine had been reunited with Gar Woods Miss America 9th? and was going to auction.
Bob
889076
Plymouth, Mi
Hi all,
And thank you for all the good advice. Now she’s running better than I have ever seen or heard! 
Yesterday we put the head back on, with the composite head gasket supplied by Simon with other new parts (head stud washers and nuts) and at the same time I was able to cure the inlet air leaks I had before, that made idle way too high once everything had warmed up. The head gasket was marked “84” mm. very thin layer of Hylomar on both sides and everything back in place, torqued down once fitted and a second time after the engine was warm.
Lapping the valves was really necessary, it was obvious at least two of the exhaust valves and one inlet valve had been blowing by for some time due to the amount of carbon deposits and crud collected over the 40+ years.
After that some valve clearances really needed to be reset.
Now the engine has a wonderful burble at idle and is way quieter than before also on the highway at 3.000-3.500 rpm.
Cheers!
Pekka T.
Fin.
Congratulations on a project well done!
Hi,
Thanks! 
Now that the 2 1/2 Litre con rod discussion touched on high speed crusing , so last weekend me and our MKV DHC were happy at GPS verified 120km/h which is 75mph to some of you. Whooohoo! It did not feel hard, but with hood down I would not push it much more, besides were not allowed to drive any faster on the highways over here. After a while at just over 4.000rpm the temp was fine while driving, but when I came to the traffic lights, there was some boiling of the water, the temp gauge however did not go higher than 90 deg C. I have an 82/83 C thermostat. So I take it that could just be considered normal, and once I added some cooling fluid all was well. Or should I look for a problem somewhere in the coolling system?
Cheers,
Pekka T. - 647194
Fin.
Hi Pekka, sounds like a fun run.
90 max on the temperature gauge when boiling observed has some candidate reasons. These gauges use ether pushing gas pressure inside a curled tube which uncurls as pressure increases. Ether has a vapor pressure of about 100 psi at 100 C so is ideal for this purpose in a dual gauge setup with similar range for oil pressure. And ether is cheap.
Does the gauge go to 100 when sender is placed in boiling water? Gauge may only go to 90 if gauge mechanicals are wearing out or if ether is getting low. The sender can be removed from the thermostat housing and placed into a pan heated by hotplate or torch for boiling test in the engine bay.
On the engine coolant side, was coolant level correct before run? Is coolant bypass line closed when coolant is warm? My experience over 15 years in hot Southern California is summer traffic shows rising coolant temperature at stops which returns lower as soon as moving, clean radiator, stock fan, clean coolant passages in block and head mean no boiling though it does enter the worry zone on occasion.
Check your oil for level, color, and presence of “cottage cheese” color on inside of rocker cover oil fill cap to see if water is getting in the oil. With full radiator and warmed up with radiator cap off if you have the water level just right to seal around the top, watch for bubble coming there to see if combustion pressure is pushing heated combustion product into the coolant. These combined checks help you know the head gasket seating condition. Bubbles indicate a leaking head gasket and also additional heat load into coolant.
These are just some of the ideas on your question. Use over a variety of conditions will build your experience base to help know if okay or needing additional help.
Off the question topic, your photo shows a steering wheel that looks a bit different from mine. If you are seeking another steering wheel, send me a note and I can send you a photo of what I could give you.
Hi Roger,
Thanks, excellent trouble shooting ideas.
I just retightened the head bolts/nuts, so I had the rocker cover and rocker mechanism out.
No signs of water in oil (clean oil, although somewhat dark) no bubbling in coolant when running the engine without the radiator cap etc all is good.
Before the head was refurbished, the water gauge would go all the way to 100 C, not a nice thing to see in downtown traffic! Used to run the heater on max and occasionally shut down the engine. Now that idle is a nice 450-500rpm burble, no problems, the two occasions of short boiling came after a run at 4.000rpm on the highway. I guess I may have had air somewhere in the head? Today a longer run, also at 3.600-4.000rpm for a while and no issues. May have also been that I came to a sudden stop from high speed, must try to remember to slow down a bit earlier! 
Cheers,
Pekka T. - 647194
Fin.
Edit: The steering wheel is original, but it has an old, worn aftermarket leather cover on it, that’s why it looks different. 
Wahoo! And just think that the period road tests say the maximum speed was 87 mph.
Inspiring and also depressing, to remember how many years it has been since mine saw 75.
Slapping out a long crease in the right hand bonnet today, it was hidden by Bondo. A DPO must have dropped something on it. Lots of grinder marks all around the damage.
Ahh, The MK IV is listed i the owners handbook as having a max of 95 mph. although I thought it was 93 mph. Possibly by a little over the red line
Not sure about with alloy rods, but with steel rods Ivan Stephens and a locally made cranks got 5000 rpm at Rob Roy. I only sat on 4500 all the way up the hill in second but with an factory 3 1/2 crank, which I found to be the fastest way. Dropping into 3rd cost a noticeable amount of time.
Hi all,
Just took the car to winter storage, I was able to do 1663 miles this summer, despite the head gasket failure etc. That’s ca 2700km so I am happy.
Also did a personal record last Friday, 90 mph (145km/h) but don’t tell anyone! 
(ca. 4.600-4.700 rpm)
It did not feel too bad although we were three people onboard so my wife was complaining that it was rather windy on the back seat! (with the hood down, of course
Cheers,
Pekka T. - 647194
Fin.
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Good way to finish out a summer driving season!
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