J head porting

Thanks for the help. I’d like to work on one port int & exh and have it flowed to see if it’s worth my time. Not sure if I should have it flowed with the stock 1.88 valve and see if I’m on the right track or have it ruff cut for 2.02 and blend it in a bit and flow it?
If you're going to do it... do not use a 1.88 tulip stocker. What you will end up with are poor low mid and decent 'for the valve head diameter ' peakf flow.
I would use either an 11/32 stem , be it 1.94 or 2.02 ...or use a 2" LS valve , 4.86 long is LS stock or a long version.
Factory valves are around 4.95 or something, that's just off the top of my head to give you an idea. You can look it up online easily.
Basically you want a nice Under head that's not in the way and has a nice angle on it and the stock valves have none of that. They're also really heavy.
Just a 1.89 dropped into a worked intake port thatvwas 1.88 will show massive gain. Buy one of each... do the 1.89 LS 1st with your porting and see what you have there. Just tape the stem to make it 3/8 to fit guide and keep the tape high on the stem enough to stabilize it but not be in the bowl at max lift.