1978 F100, 300ci....anyone have any problems with headman headers, where one of the collectors runs smack-dab into the cross member? looks like there isn't enough room for the muffler guys to run the exhaust past it. I can't be the only one....but I've searched for fixes and really haven't seen a lot on the subject.

 

I don't have this year of vehicle, but I remember hearing this a lot. The headers are designed for the 80+ front end and then since the engines didn't change, they say they fit earlier years too. But then they hit the cross member.
I believe F-250 Restorer has some headers on his though, and dealt with and got around this problem. If I remember right, it had something to do with a big hammer. That and grinding a little notch in the cross member.
Maybe send him a private message if he doesn't see this?

 

I didn't hit the c.member with mine. I have a 75 with an auto trans. However, I routed one tube from collector and around the driver's side of the trans, around the trans, and then joins the other tube. It is super tight. I did have to notch the frame about 1/4", right across from the starter. Oh, wait ... it does touch the back side of cross member. I got tired of it being so crowded down there and am swapping to the Clifford shorty headers, wrapped, to prevent heat issues. Also, I'd recommend swapping to either a mini starter or an efi small starter prior to install. Once that header is in, if your starter fails, you're going to be using C clamps and pry bars to swap your starter.

 

Thanks to you guys for the replies. Yea, manual tranny here so the c-member is directly in front of one of the collectors. I saw a pic (somewhere, and I can't find it again) where a person cut out and welded a "tunnel" into the cross member for the exhaust to run through it.....looks like that might be my only option if I want to stick with these headers. That being said, with all the reading I've done, I might have issues with the Offy DP (Eldebrock carb) and heat from exhausts. costs for fabs probably the same as searching for EFI exhaust, so might as well press forward. I do have the heater plate and coolant running through the Offy.
Also installed a mini starter while I had it on the motor stand.

 

I ran an Eddy carb. No heat issues due to Hedman. The bowls are situated perfectly for that carb. BUT if you want descent mpg, I'd run a cool air intake to the air cleaner.

If your engine does not big boom mods like ported head, cam, and over-size valves, performance ignition, I'd recommend the efi exh. manifolds. You lose 'bling,' but you'll also lose heat and rattles.

 

You get a piece of fairly thick wall pipe ( 3/16"-1/4" ) with a inside diameter large enough to pass your collector thru ( or even slightly larger ) . Cut out the area of your crossmember you need the clearance at. Then weld in the piece of pipe. I also like to add a few gussets to it. Make it even stronger then the stock crossmember.

If you have a heat issue with the Edelbrock carb add some kind of thick gasket and or a composite carb spacer. And if that's still not enough make up a heat shield plate that will go between the carb and manifold.


WHAT! Mr. Headers is recommending EFI manifolds???????

 

That's funny. You are right though. I can't understand choking an engine that has been built to flow with larger valves, cam, porting, and then installing efi manifolds that were designed for an engine that makes what, 150 hp? That, for me, and anyone else with a brain, redefines the definition of insanity. Lol, I guess that's fairly plain spoken. But...headers have issues. Heat is one.

* I was surprised to hear in a Summit Racing vid., that shorty headers magnify the low end performance of an engine.

 

Think of the Headers vs. EFI manifolds like a a higher ratio rocker arm vs. a cam swap. The rocker arms will give them some improvement without all the hassle and possible issues that can pop up with a cam swap. Would the cam swap give a person more performance then a rocker arm swap? Sure, but the rockers will give you some improvement with a fraction of the cost and hassle.

And the whole "it was designed for 150 hp engine" could be said about the head too. But that hasn't stopped any of us! Like I've said many times there is a lot of room for improvements on the flow of the EFI manifolds. A few porting tools/supplies and a bunch of time and you can improve their flow. They may not out flow headers but they will out flow any of the stock manifolds.

Before:




After:



And I could have taken it even farther then I did. But I didn't want to get into the sealing area on this one.





And as far as the issue with heat on the headers. The best solution is a very expensive one. A good ceramic coating will cut down the heat, big time. But it could cost double to triple the price of the headers.

 

Very well said. It looks good. I'm sure it will flow much better than before you ported it.

However, when all is said and done, you still have a 1.75" collector, making a max. hp with dual pipes that size of 217. Both the Hedman and Cliffy headers have 2.5" collectors, allowing with dual pipes a total of 463 hp.

I am well acquainted with the heat issues associated with headers, and fitment too. But, I cannot help but KNOW that putting efi's on an engine with larger valves, ported head, cam, is like asking an athlete to run a race, and only allow him to exhale half what he is capable of. One good analogy deserves another. HALF! The efi's flow less than half what headers are capable of. That is the bottom line--the argument closer. I rest my case.

I think efi's should mark a line between mild and wild. If a person plans to run in that hp range, around 200 hp, then efi is the supreme way to go.

 

Ah no you don't, I believe the opening on my ported one is right around 2". The stock opening on the EFI's are 1.75" not the exhaust pipes. I believe the stock pipes were either 2" or just a hair larger. The outlet is the only restriction on those manifolds and there is plenty of meat to open them up. I wish I had access to a flow bench. The head will be the restriction way before the EFI manifolds are on 90% of the 300's out there. Most 300 builds don't need headers.


I feel 220 to maybe 250 hp should be do able with the EFI manifolds. I would be surprised if your "wild" engine hits 300 hp. I don't like the whole mild/wild labels. Because I know of plenty of 300's out there that are running headers that I would not consider anywhere near wild. I see it more as the persons personal preference and threshold to the BS/hassle as to whether they run headers or manifolds. If they can deal with the heat issues, exhaust leaks, more engine noise ( which I actually like ) , the P.I.T.A. of starter replacements and having to replace them more often then manifolds. Oh yea and can't forget the benefit of bragging rights a person has when they run headers. Just remember full length headers give you more bragging rights then shorties do. And Zoomies make you king of the headers. Not everyone is trying to squeeze out every hp they can. They are trying to make a improvement to make their engines perform better then stock. And the EFI manifolds are better then the carb exhaust manifold. But if you want a step better then the EFi manifolds then headers are the way to go.You just have to be willing to deal with what comes with running headers.

All of that being said, all of mine are getting custom headers. But we are running @POL_Sarge's thread off the rails here. So back to his thread, hi-jack over.

 

No worries here!! I'm learning a lot from reading your submissions, and thank you all for that. I was just hoping that I could run into someone that has encountered the same exact issue that I am having, and show me what they did. So, please keep talking!! maybe tell me what kind of ignition setup is best for the 300. all I have now is factory points and vac adv dist.

 

I don't know how bad the collector interferes with your cross member. But you are either left with two options modify the crossmember or modify the headers. It all depends on your fabrication skills and the tools you have access to.It may be possible to cut your header tubes and redirect the collector to clear. But this would require welding on some fairly thin tubing. And depending on your truck may put the exhaust hanging down too low or too high. It's hard to say with out actually seeing exactly how bad the issue is.

Your 78 should not have points unless someone swapped in a older distributor or engine. Your engine should already have the best factory ignition set up that was offered on the 300. You should have the Duraspark II ignition set up. It's easy to tell this distributor from the others. The DSII distributor cap is a large diameter fairly flat cap with male type spark plug wire towers/terminals. This set up will have a aluminum ignition module on the inner fender panel.

Here's a picture of the DS II set up.