Subject: 81 F100 flare side 4x2 with 300 six/ T18 trany

Issue: The head pipe that was on the truck/motor was loose at the manifold and the other end looked like it was cut as it had a short pipe on it to think what was left of the cat and then 90* pipe out the side. My parts truck (81 F100 LB style side 4x2 300 six/SROD) had a good exh system but the head pipe was cut when the PO removed the motor.
I also did not want to install any cat when I install the exh system back in my project. I was able to install the tail pipe, muffler and intermediate pipe.

So my fix was to get a new head pipe and long intermediate pipe in place of the cat and hook it all back up but.......... the new head pipe has a different flange than what I removed from the truck.
Truck has a cone on the manifold, it is part of the manifold not a stuck gasket, that fits into the head pipe to make the seal.

My new head pipe looks like it uses a gasket as it has a flat lip with a smaller pipe in the center the "donut" would fit over and make the seal. I just cant see how this would work with the exh manifold as I have never seen a exh gasket like that.

My questions is, does anyone know what the stock manifold exhaust flange to head pipe looks like? I will try and get pictures of the 2 pipes when I can.

To add to this I think the motor is a mid 80's from the color (gray) and some other items that were on it when I got the truck. So I don't know if the manifold is from the truck or what ever the motor came from. If I had the money I would go EFI manifolds and deal with a Y pipe to go into the stock exh but I don't have the money to go down that path.

Thanks in advance
Dave ----

 

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Thank you Bill.


It looks like I have the right head pipe as it uses gasket 9450 at the manifold.


It was my fault for not looking deeper when I bought the head pipe if it needed a gasket or not as I thought the parts I had were for the truck, live & learn.


I see Ford made a non-cat head pipe. I have not seen that listed any where when checking the web auto parts stores and why I did the extra pipe.


It looks like I will be cutting this $80 head pipe and welding the old cone flange on to it to make what I need.


Thanks again
Dave ----

 

Dave,
I have an extra set of EFI manifolds, if that would help.

 

Your twisting my arm
I have yet to get under to see what all it would take to make what I have work but I am sure EFI manifolds would be lees work and have better out come (power) to boot.
I will PM you some time this weekend.
Thanks
Dave ----

 

Kurt, PM sent.


I have a question for all, what does every one do for a "Y pipe" when swapping over to EFI manifolds?
I have been looking and you can not get just the Y pipe with out the cat and that is about $230+
Pipe only number I have found is Walker 45166 or Dynomax 45166


Or do you get 2 pipes made at the local shop to fit the manifolds and make up the rest to fit?
Thanks
Dave ----

 

I'll be installing the Walker 15739, probably w/o the cat.
I also have a great muffler shop in Apex if you want to get a price from them to make you a y-pipe.

 

PM sent you twisted my arms.


With the Rock Auto Y pipe I can swing it with sending the wrong head pipe I have now back.
Then going from the Y pipe to the stock intermediate pipe I can get something to work.
Thanks
Dave ----

 

Got a deal on EFI manifolds I could not pass up.
I ordered gaskets & Y pipe last weekend.
New gaskets are here and the new Y pipe should be here tomorrow or Friday.


I did a little more searching what all has to be done when switching from the stock log exh manifold to the EFI ones.
Looks like I need to make up a heater plate to to plumb hot water thru that fits on the bottom of the intake to help when it gets a little cold out.
So will be finding plate I can use for that and pick up fittings to plumb it.
Dave ----

 

Offenhauser Heat Plate for Ford 240 300 6 Cylinder To Warm The Plenum, Aluminum | eBay

 

Thanks for the link as I did not look there.
Think all the ones I saw were $85+s/h and I could not see spending that.
Dave - - - -

 

I just got the 45166 Y pipe for when I do mine (I still have some porting & heat coating of the manifolds to do) as the rest of the system back is new. So if you don't want to run a cat, or have a new or different one you want to use, then go that way. I had read on the 300 forum that just the Y pipe like I did was hard to get these days, but don't know. I got mine a yr or so ago when I was collecting parts and it was a I think 1 or 2 day order delivered to my local Advance Auto.

If you go two individual pipes from the manifolds to (?) however you want, but basically to a big Y (Like a 2-1/2"+ single exit with appropriate in) - or two exhaust all the way out, you can either have them made or get the factory ones at the JY. If you go JY route, those factory head pipes are a good find if in good shape. I guess all mfgs including Ford had to prove reliability and/or warranty the cat + headpipes for an extended time due to Fed regulations, so the pipes were better metal than the cheaper aftermarket. I don't seem to get to the JY very often, but maybe you do.

I've actually been looking for a modern factory new takeoff for the system going back from the 45166. Mainly trucks for the big single pipe, and any of the big 3 are putting some good power, so the exhaust systems are plenty free flowing for our use IMO. And, they are much better quality; I just hadn't been able to get them so far when I see a good one for cheap. I just missed one around Christmas.

But of course, and exhaust shop is quicker and can make anything you want. What did you have in mind?

 

Jim, What I have found on the 45166 pipe is you cant get it any more. I checked 5 or 6 on line places and the number either does not come up or N/A. Also from what I found it was about the same time you picked up your pipe that it was getting harder to buy one. I do have to say I did not go into any of the local parts stores to see if they could get that pipe but my thinking is if I could not find it on line the kid behind the counter could not either.


That is when I started checking for the Y with cat (walker 15739) and it seams everyone can get that.


My plan at this time is use the EFI manifolds> walker 15739 Y pipe> try and keep the larger pipe of the Y pipe going as far back as I can before reducing to go into the stock muffler & tail pipe as it is like new from the parts truck.


I also don't plan on using the new cat because from what I have found on line they don't check for any of that stuff on my year truck. If they do then I will install it.
The other reason for no cat is it would be nice if the truck had a little exh note and cats act like a muffler. Then again that big long round stock muffler I think will make it (to) quiet.


As for having a shop do up pipes/system the truck is far from getting on the road to take it any where, most places are closed on weekends, only time I have off, and would like to run it to move it around as needed and keep my hearing


I will post what I end up with but it may be some time before I can have it running for a sound test.
Dave ----

 

It's a shame to have to pay for the cat setup if you're not going to use it, but I personally do like the Y pipe setup for simplicity.

If you do the individual pipes, either JY or fabricated, could go into something like this in the correct size for your needs:

Universal Custom Exhaust Y-Pipe 2.25" Dual 2.5" Single Aluminized Steel | eBay

There are also 2 in 1 out mufflers.

If you do go the Walker Y route, make sure and look at that rear manifold short pipe; they are notorious for being restricted there. The one I got is that way; I plan to run a hole saw through it, or maybe a die grinder.

You know, another thought is to run the cat as that will put the end of the exhaust farther back, then a straight piece from that to a cheap glass pack type muffler. With the cat acting as a bit of additional sound deadener, the open muffler would maybe get it where you want sound wise.

 

Thanks to Kurt, aka: Tarheel Blue I now have a set of EFI exh manifolds.
I ordered and received a Walker Y pipe 15739 that comes with a cat as that is the only way to get the Y pipe now days.


As it has been posted you should look inside the Y pipe to make sure it is not choked down. Mine looks great and if I was looking for every ounce of high RPM flow I would then clean up the welding flash.
Kurt, yes my Y pipe is a lot better than yours and why I am not going to touch it.

Dave ----