Ford Racing M-9430-T50 - Ford Racing Hi-Flow Shorty Headers - Overview - SummitRacing.com and yes that's ID, they use a ball and socket collector so yes it will bolt up to the 5.0 stock y-pipe, and adding headers and keeping the stock restrictive exhaust dosent make much sense to me anyways lol.

 

and shorties dont flow that bad guys, my pace car has made 300+whp through a set of bassani equal length shorty's, not going to argue that i could gain some power with a set of longtubes but thats not bad for a set of crappy restrictive shorty's imho.

 

I bought the M-9430-T58 manifolds and 1 side has a 2-1/4" collector outlet and the other side has 2-1/2". So I know it has the ball socket that Ford has been using since the 80's. What I was saying is the outside diameter of the stock 5.0 down pipes are 2-1/2"(that's the very widest part of the flare on the 2" pipe which means if your source of information is correct then the stock down pipes of a 5.0 would slide right up inside the collector and leak like a mother****er.
I rest my case.

 

Yes but there's more to an exhaust system than the headers, I'm willing to bet that car has a complete aftermarket exhaust system so it's not a fair comparison.

The real problem with these trucks is the cork like factory Y pipe and cat, that is the reason shorties alone are a waste of time on the trucks.

 

yes of course it has an aftermarket exhaust,

its not the headers fault that the y-pipe and cat are restrictive so why blame them? if you put a set longtubes on you are going to run a better exhaust system right? so why in the world would you not do it with a set of shorty headers??

 

Yes exactly. My comments were to explain why shorties get a bad rap with the truck crowd, that simply swapping them in place of the manifolds without changing anything else is a waste of time.

 

if what you are saying is correct then the flair would be less than a 1/4" on each side of the pipe of a 2" internal diameter pipe. don't seem right to me, ill go out and look at some of my h-pipes out here but i don't remember seeing a ball and socket with such a small socket.

 

got ya, must have miss read what you said, ya a engine is basicly an air pump, if you want it to flow air better you need to upgrade from where the air enters the engine all the way to the point where it leaves the system, upgrade something in the middle and leaving the rest untouched wont help much.

 

Yeah it's about 1/4" on either side but being on such an angle it looks like more than 1/4". It's about 1/2" of steel bent at nearly a 45* angle so it ends up being 1/4" on either side. Give or take.

 

Very very true!

 

The collector on the header may be 2.5", but the actual pipe size of the cross over is 2" OD. The ID of the outlet is only 1.875" as shown on the head on the left.
I modified the one on the right for 2.5" outlet pipe size. I made a 2.5" crossover, along with the rest of the system, which is 3".
These are the 5.0 headers. I have them on my 351/408. I bought the 5.0 headers because I didn't need the EGR connection.
Looking at my headers and comparing them to the 5.8 headers, they look to be slightly different.

 

^ now that's the reliable information I was looking for.
5.0 having less than a 2" ID collector and the 5.8 having the 2-1/2" ID collector.

 

looks like while i have the motor out of my pace car ill be opening up my bassani's, good info.
my original point was the OP will not be chocking his engine with his frpp shorty's, they will flow fine with room to spare with a good exhaust behind them