How much power gain with longtubes over factory manifolds?
 

My car has longtubes now but I am starting to not like having them. I don't like the thin metal ticks, or the machinegun sounding rasp at common rpms, I don't like how low they hang etc. Considering swapping back to stock manifolds (or the new Hooker manifolds if they fit) and a custom 3" y pipe with a good merge. How much will the manifolds themselves hold back power? I know the swap from stock to headers/ory is like 20+ but how much of that is y design?

A good y-pipe design definitely helps add power over the stock y-pipe. Are we comparing a ORY to stock here?

Off road yes or one with good modern high flow cats.

I can't say for sure exactly, but I'm betting a good 3" ORY will provide as much gains as the long tubes themselves, when comparing to the stock components

So you think swapping to stock manifolds and a good ory from longtubes/ory would lose me maybe 10-15whp or so theoretically?

Yes theoretically

If you have old slp headers then the more modern design are a lot better and don't hang nearly as low

Nah mine are Speed Engineering.

After having just finished an install of the blackheart longtubes (and their matching dual system) I can say theirs tuck very nicely. I think that the exhaust hangs a little higher than the factory exhaust did, if not it's right around the same height. Looking forward to being able to easily cruise over speed bumps again! lol

That setup is now on my radar since I made this post. I tracked down some installed pictures and I am really surprised by the ground clearance it has. I wish there were more driving videos of it. Not 100% I like the sound of the mufflers yet.

A catted ypipe might help

I haven't been able to fire my car up yet (waiting on a tune) but as soon as I do I'll post a vid.

Worst case the mufflers are only clamped on and you could add something else to the system (or an exhaust shop would fab something as well)

And the exhaust won't make your eyes water....

How about the Thorley LS universal headers,, short tube twin Y..
I have their Tri-Y header on my jeep it definitely opened it up on long hills.

Tri-Y's are supposed to be better for the low and mid range, with the top end only a little less than full 4-tube headers.

I don't think the Blackheart headers are long tubes. I think mid length as to why they tuck up so good. A buddy also just installed their whole system. Said he's just chasing some little rattles here & there. He's happy with it.

They look to have bot midlength and longtube options. I am curious what the ground clearance difference is between the two header options.

A midlength header will always have more ground clearance simply because the collector is further off the ground, and angled up into the engine compartment.

Yeah I realize that but I am curious about their clearance anyway.

I went TSP 1 7/8 to 3 inch ORY and love it. Bought the complete system from them for a little over $1k and install was a complete breeze.