Hoping this is the right place ask this question. But on with my thinking. Having this big proplem with leaks and gasket sizing, What my Idea is taking headers and running a weld around the outside of tubeing and then grinding or milling the flange smooth to where its flush up against head so when you insert gasket all of it is use.. This on a 2 wheel 390 pickup. There are two things that I will never understand the design of head to header flange and why they put the collecter right over the crossmember. Thanks for any input on this or If anyone has try this, thanks in advance.

 

My experiences with headers have not ended on a positive note. They always leaked, pain in the butt to work with or around. It certainly made changing starters fun. The best thing I can say about headers is they take up very little room in the dump. Welded duals off the manifolds is what you should shoot for.

My 2c
Trail Rider

 

GWB, this is what happens when you tell someone if their is a will, there is a way. I put a mild built 351C 4V in 78 4x4. Every thing that works on a modified worked like engine mounts, ect.. exept for exhaust manifolds. I could not find a set of 4V manifolds for the engine so I had to go with headers. Of course nobody made headers for this application due to the larger size ports but were readily available for 2V engines with smaller ports. What I had to do was grind the welds flat on the engine side of the flange and align a gasket on the flange and mark where the ports were larger. Then I had a guy I know build a large weld around the outside pipe, it took three passes. Then I had to grind the port out with a carbide bit in a die grinder. To make sure they sealed up I double gasketed the flange. I never thought something like that would work after some bad experiences with double gasketing oil filters, but it seems to work ok.


78 Ranger 4x4 351C-4V
83 Ranger 302

 

Thanks for the reply, try it and it working so far, ended up taking a set of old headers cutting tube out. Then bolting headers and flange to a old head togeather, Welding the vertical gaps then removing bolts and cutting the top taps off below the bolt holes, then welding the hozintal, Now have flat flange against head and header bolts go in so easy and also enough room to get your hands in there. maybe someone in the header bussiness will read and think just a little bit,(note: good header did not have full flange across but old set did)

 

Well here's my 2 cents on this ..
If you all don't know me yet I have a Pull Truck I call ShaZam.
Last year I was running 2V heads and had a set of Headmen wheelwell headers on it. Well this Year I went to Vintage 1969 Boss 302 4V heads. Now if trying to find good headers for a 1978 F350 4X4 running a 400 isn't hard enough try to find them in the 4V flang plates. Damn near Impossiable..But thanks to the internet and lots of surfing I found a few places that could help me out. 1st place I found was Headers By Ed .. Great Guy told me everything I needed to know on how to build Custom header..After thinking about it for a while I went surfing some more due to the cost, Big Bucks...Found Stahl headers, they had a weld up kit for a big block chevy that they said I could make fit for $285.99. And they had the 4V header flang plates I needed. Well after 3 hours of tring to get them to fit I gave up and Threw them in the corner And put the headmen's on it, My desk top Dyno said I'd lose 70 Hp but I figured I run them anyway.
Well after the first weekend of Pulls I got spanked pretty good, But I did take a 3rd in open stock at the 2nd pull last weekend. Well after shooting the bull with the guys at the pulls one guy said he had some left over J bends, Will before you knew it I was dragging them out of the corner and I got the Saws-all hot and started to make little pieces out of the Stahl headers. I started by tacking 2" stubs to the flang plates and then heating the pipe up and pinning it to fit the big 4V openings, once they were formed I welded them up and ground the back side flat. Then I bolted them to the engine and started to make the pieces fit.Well after 8 hrs of this that and the other I had one sides done, the other side went a lot fast only 4 hr. All the pipes are 37" long and tucked real close to the frame just like they should be for a wheelwell exit header.The Amazing thing is I only needed 2 J Bends to make them all fit right. On first start up no header leaks.. Cool ;-)

I'll leave this message board with this. Making my own set of headers is one of the best an most rewarding things I've ever done.
Now next week We'll be out Kicking some Chevy Butt at the Truck Pulls with a Full 650 Hp..

DG Homa and ShaZam

 

[font size="1" color="#FF0000"]LAST EDITED ON 03-Jun-01 AT 00:45 AM (EST)[/font][p]some header companies also haven't caught onto the fact that the smaller port emmisions FE heads (read most anything made after 1966-68)have the exhaust port lowered 5/16th of an inch, this leads to header leaks very easily. you can try slotting the bolt holes and lowering the headers some too, it might work.

 

I have had my share of exhaust leaks on my header equipped 390. I bought a pair of Doug Thorley headers and they came with gaskets from Byson Manufacturing and with this combination I have not had a header leak in the five year period that I have had the headers on the vehicle. I would highly recommend the Byson gaskets as they fit the port perfectly. There info is below.
Byson Mfg. Inc.
1845 Sampson Ave.
Corona Ca. 91719
909-734-3850

 

I agree!!! I've had my Thorley's on for 3 years with the Byson gaskets and absolutely not a hint of a leak. The gasket is fairly thick and looks almost like rubber. The Thorley flanges are also extra thick and you need longer header bolts (supplied by Thorley) than Hookers or Hedmans.

ROL also has a reputation in the racing industry for the best gaskets on the market!!!

'82 F150 2WD w/351W (orig 300 I6)
Slik