65 Valiant 273 dual exhaust
Does the pressure test need to be done at a shop?
no
you just drill a hole in the pipe on the engine side of the muffler and braze a foot or so of brakeline into the hole. Then run some some vacuum line up into the cab, install a low pressure gauge in the end and finally
take it for a power-run.
Note at what rpm/speed the pressure peaks and the value.
Less that 2psi is the target
more than 4psi you can really feel the power loss*.
But if it doesn't hit 4 until top of second gear, well, that's a judgement call cuz with 2.76s that's 74mph@4500, with 3.23s it would be 64 mph. This will change as you hop up the engine and it starts to process more air.
* well you might not feel the power loss if you are used to it,lol. but if you go from 2 to 4 within hours, you sure will.
