The Answer to 4V headers on 2V heads

[EBSTANG]

Bolt pattern is the same. The 4V header will bolt up to a 2V Head. It can even seal the .01" raised port location, from stock. Those are not the issue.

The 4V is wider on the right side of the port. The right side exhaust port wall (as you face the head, in the pics) is offset (widened) on a 4V head. Look at it, in relation to the upper header bolt(s).

A "4V header gasket" would make contact (seal) with the 4V header, in that right side area, but the "4V header gasket" would not make contact (seal) with the 2V head surface since the 2V head surface is offset to the left. (in comparison to a 4V head)

A "2V header gasket" would make contact (seal) with the 2V head, in the right side area, but the "2V gasket" would not make contact (seal) with the header, since the 4V header "right side sealing surface" is not offset left.

With either gasket, 2V or 4V, you would not get a compression seal on the right side of each exhaust port. Bolt them up and they'll look good since the header flange will cover this up (from view) but underneath you will not be compressing the header gasket (between two matched metal surfaces) in this area. Incomplete circumferential-peripheral compression around the port. No seal.



...here's a edited image to show the widened gasket sealing surface on the aftermarket TFS Head. (for future reference) These TFS Heads (and maybe other aftermarket heads) can accommodate either 2v or 4v header gaskets. This TFS head is a 2V head with the sealing surface width of a 4V.

 

[c9zx]

I thought the conversation was about TFS power port heads, not OEM. Chuck

 

[TommyK]

Bolt pattern is the same. The 4V header will bolt up to a 2V Head. It can even seal the .01" raised port location, from stock. Those are not the issue.

The 4V is wider on the right side of the port. The right side exhaust port wall (as you face the head, in the pics) is offset (widened) on a 4V head. Look at it, in relation to the upper header bolt(s).

A "4V header gasket" would make contact (seal) with the 4V header, in that right side area, but the "4V header gasket" would not make contact (seal) with the 2V head surface since the 2V head surface is offset to the left. (in comparison to a 4V head)

A "2V header gasket" would make contact (seal) with the 2V head, in the right side area, but the "2V gasket" would not make contact (seal) with the header, since the 4V header "right side sealing surface" is not offset left.

With either gasket, 2V or 4V, you would not get a compression seal on the right side of each exhaust port. Bolt them up and they'll look good since the header flange will cover this up (from view) but underneath you will not be compressing the header gasket (between two matched metal surfaces) in this area. Incomplete circumferential-peripheral compression around the port. No seal.

The sealing issues when using 4V headers on 2V OEM heads are well documented. Some people get lucky and don't have an issue while others can't get them to seal. I don't know if that is a function of header brand or just the luck of the draw. I know Sanderson makes a special copper header gasket which supposedly addresses the sealing issue.

The pic of the TFS head Chuck posted seems to indicate there might be less of a sealing issue but the only way to know for sure is to try em.

If you are under a time constraint for returning the headers you bought then experimenting at this stage of the game might not be practical for you.

It should would be nice to know definitively what works and what doesn't though.

One other thought. If you decide to return the 4V headers and use 2V headers you may want to consider the possibilty that there may be potential chassis fitment isues due to the raised exhaust port. It might be prudent to make sure they don't need to be modified before you have them coated. I know on my FPA headers on my 460 I had to massage one tube with a hammer near the steering box.

 

[EBSTANG]

I thought the conversation was about TFS power port heads, not OEM. Chuck

Yes it was, I was studying the difference between the 2V & 4V and came up with my explanation...and now that I see your pic of the TFS head I see that the "right side" gasket surface is widened, I'll have to agree that would allow both gaskets to seal. Just brought that up to Stan @ FPA and he then said that it may work if that "landing area" as he called it is wide enough to get the gasket squeeze I spoke of. Well, atleast we'll all now know the answer for the 4v header to the stock 2v head question, (Doesn't work) so the next guy looking for that answer will have my explanation to look at. I'm certainly glad you're apparently right (and persistant) to hang with me and send that pic. After I took the time to type out my explanation, I really learned what I was looking at and when I saw the pic you attached I knew what to look for.

(TFS-51616204-C00) 195 Cylinder Heads look like the pic you sent...sooo the aftermarket, TFS and probably others widened the flat gasket surface, below the upper bolt instead of having it offset left (2V) and offset right (4V) and that allows the use of either gasket too. Pretty cool!

THANKS CHUCK!, CHUCKIE!!! CHUCKARAMA!!!!, THE CHUCKSTER!!!

dancebanana

 

[c9zx]

Follow this link, post #2, about half way through the post, item number three. They used TFS Power port heads and Hooker Comp 351C 4V headers.

http://www.gearheadtalk.com/forums/showthread.php?33187-Trick-Flow-PowerPort-Cleveland-heads

EDIT: I didn't see your post until I'd written the above. You are very welcome, glad to help. Did your machine shop ever say precisely what problems the CC OEM 351C heads have? Just curious I suppose.

Chuck


Forgot to add this to the edit (old age and long day). If you go with the TFS heads, your Torquer is not going work, HUGE port mis-match. It looks like the Edelbrock RPM or RPM Air gap would be a good match.

Good luck with the build.

Chuck

 

[EBSTANG]

Follow this link, post #2, about half way through the post, item number three. They used TFS Power port heads and Hooker Comp 351C 4V headers.

http://www.gearheadtalk.com/forums/showthread.php?33187-Trick-Flow-PowerPort-Cleveland-heads

EDIT: I didn't see your post until I'd written the above. You are very welcome, glad to help. Did your machine shop ever say precisely what problems the CC OEM 351C heads have? Just curious I suppose.

Chuck


Forgot to add this to the edit (old age and long day). If you go with the TFS heads, your Torquer is not going work, HUGE port mis-match. It looks like the Edelbrock RPM or RPM Air gap would be a good match.

Good luck with the build.

Chuck

Doin the air gap, thanks again!