Anybody bolted them up to a stock 5.0 Y-pipe? I'll be pulling the motor on my wife's '92 F-150 aka "Big Red", and I have the stock headers from my Lightning (went to longtubes) hanging on the wall. Wanted to throw those on in place of the old manifolds. Will the y-pipe bolt up, or will the 2.5" driver side and 2.25" passenger side collectors be too big for the flare on the pipe? What size is the stock y-pipe? 2.25"? 2"? I know the real solution is to build an appropriate, mandrel bent y-pipe, but the budget is tight, and this motor needs rebuilt.

 

bUmp

 

I don't think they will bolt up to the pipe , the 351 is wider than the 302 , but with some modification they may work......Lew

 

They would bolt up. I run lightning shorties on my motor.....BUT the ball flange will be too large for stock y-pipes. I built a custom y-pipe to accomodate. You can see the pictures and the difference between the restrictive stock pipe (and flange differnce) and my custom ypipe on this thread....I posted pics.

https://www.ford-trucks.com/forums/1034582-y-pipe.html

 

I figured, as I've always heard they exit in the same place and angle as the truck manifolds. So the pipe won't even seal against the headers you think? I guess I just as well take a little longer and build a new exhaust as I put it together, I'm thinking 2-1/2" duals no cats back to a big magnaflow 2 - in, single 3" out muffler

 

I don't think it would seal.

I have 2.5" into single inlet 2.25" dual outlet Magnaflow.

 

Well, I found out last night. Working on getting the motor out of the '92, got the cat-pipe pulled off in 1 piece, just in case I need to re-use it. Set it on the floor, went and grabbed one of the lightning shorties off the wall, tried to set it on the pipe flange, the collector went right over it! As in the headpipe fits inside the hole of the collector! Definitely not going to work, LOL. The manifold outlets and headpipes appear to be 2"! So, stock is 2" dual pipes into 3" single, then down to 2-1/4" single where it comes out of the second cat. No wonder this thing is such a turd! What were they thinking? I'm going to try my damndest to get a new exhaust on this when it goes back together, I may have to run a dump instead of a tailpipe for a while, but I don't want to put this crap back on!

 

Hivoltj....dropped you a pm. Yep stock Y-pipe is ridiculously small. You can see the comparison in size in my link a few posts up between my mandrel 2.5" and the stock piece.

 

Where did you put the 02 sensor?

 

I welded in a 1 inch piece of pipe right before the merge collecting a exhaust sample from both banks....basically the exact same position and manner as stock, except there is of course right before a cat and not a merge collector.