Would there be any real benefit of cleaning an intake manifold?
Either measurable in any way, or perceived?
Valve deposits removed creating a more complete seal potentially I proving compression.
And sucking it in through a couple different vacuum lines seems to help the engine feel more responsive with light throttle inputs.
OP. If those deposits are from the oil mist and combustion gasses that got by the rings then try using mmo or a 2 stroke oil.
My grandpa always said "like dissolves like" which can be translated as 2 similar based things will mix,meaning the cooked oil vapour should get soft and come loose if you add oil to it.
Try soaking a shop rag with 2 stroke oil or mmo and left it sit on top of the deposits overnight.
I had hard carbon deposits on the old pistons from my Harley and they were sitting on my table in my shop.
I accidentally spilled either mmo or 2 stroke oil and some of it got on the carbon encrusted pistons.
I went into my shop a few days later and saw the piston that got spilled on the carbon looked kinda soft,and I wiped the piston clean ONLY where the oil got spilled,the rest of the piston was still hard crusted carbon.
So on one piston I coated the entire top with mmo,the other one with 2 stroke oil and left them sit. The next evening I go to check them out and on both pistons the deposits came off however the mmo one was much softer and easier to clean. The 2 stroke oil one was a bit harder to clean off.
So I know these products will clean up hard,baked on,cooked deposits if given time to absorb into the affected area.
After seeing what they did to the insane build up on my Harley's stock pistons I began using mmo in the same fashion as seafoam,administering through a vacuum line trying to saturate all the deposits possible.
With mmo I stall the engine pouring it in as fast as it will accept it then once stalled let it sit for 20 mins to a half hour then take it out and drive spiritedly.
I think the best way is overnight though.