Wouldn't the number stamping by the distributor boss confirm what he's got for sure? Air cleaner looks like the one I had on my 235...I can't recall exactly now the details of it, but the entire engine looked very similar. Manifolds look different, though...can't quite put my finger on how...
Low pressure 235 Check out this site and note the smooth contour between the 1st and 2nd plugs. http://pugetsoundvintagechevrolet.org/Programs/6 cylinder engines with photos.pdf
Engine Serial #'s & Intake Manifolds Yes *but* GM Canada used a different series of serial #'s back then so maybe a Canadian FSM would be of help to decode the engine # , not so much the American FSM . The intake manifolds have a casted ' ear ' that sticks up along to top edge of the front runner , when it is to be used to mount the horn on trucks , two threaded holes were machined into it ~ many were made with the ear but not drilled as they were used on Passenger cars . Minor details no one really cares much about . The main thing here is : jnycnuk do not be concerned that the oil pressure seems low on this engine ! it's made that way , as long as the oil gauge raises up off the peg as you are off idle , it's fine . The other oil pressure / flow test is : when warmed up , set the engine to a fast idle and remove the oil filler cap , peer in at the rockers and if there is oil dribbling out of the weep hole in the middle of the visible rocker , you're good to go ! just tune it sharpish and HOT CHANGE that oil ASAP , use the thinnest multi - vis oils you can , like 5W-40 , synthetics are best , it'll take a couple of oil changes to clean up the inside of the engine and flush out all the old sludge from the vintage parrafin based oil that's in there now , no worries , just drive it as much as you can while you're cleaning and tinkering it back to robust health .
