can someone please tell me of these components which is the most restrictive...
stock LT1 manifolds, stock y-pipe, 3 inch hi-flow cat, stock catback w/ flow muff....i know the gutted cat is not the most restrictive , but will the 3 inch hi flow turn into the most restrictive part of the list or will i still be limited by something else?
TIA

 

The most restrictive part of a stock LT1 exhaust set up is the Manifolds hands down.

 

Although I would guess that best bang for the buck for removing/replacing a restrictive component would be the muffler.

 

Manifolds/y-pipe, then the muffler, then the catback pipe (i pipe).

 

so its safe to say the hi-flow is less of a restriction than my flowmaster?.....guess buying that cutout was a good idea

 

yea, manifolds no doubt
just look at the rwhp you can gain from going to headers

 

headers is the best thing to replace first

 

Manifolds, hands down. Most restrictive pieces of .... in the whole system.

Without having a dyno to prove it, I would guess-timate that the muffler would be about as restrictive as both cats? Either component would probably be worth around ~5 rwhp or so? All I know is that when I put a pair of supposedly "hi-flow" cats onto my '81 Z28 (w/383 and true duals) it was like throwing an anchor out behind the car! I'm sure you could pick up well over 30 HP by going to headers, custom Y-pipe, no cats, and a cutout!

 

Usually whatever is closest to the engine is more restrictive... That's what I've heard anyways.