Fitting TTi headers on a 273

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67 Barracuda uk

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Hello people.
I could do with some help please.
I’m in the Uk
I purchased a set of headers for my 67 Barracuda.
The new headers have a different port size to the 273 heads.
When I put the gasket against the head - it looks to big for the ports.
I’ve checked on TTi website and the headers are for a 340.
When I purchased them I didn’t realise the headers for a 273 are a special build.

Below is the information from TTi website about the special build.
*For 273-318 Small-port cylinder heads, with the port diameter 1.09w x 1.55h. Applications with these small-port cylinder heads, will require modification to the ports for our headers to seal properly. Additional material will be added to the ports for headers to seal properly. Modification will be done prior to coating. Please allow additional time for the modification and the coating process, approximately 4-6 weeks. Headers requiring modification is considered a "SPECIAL ORDER".

My problem is I can’t send them back to TTi because it would cost a fortune in shipping from the uk.
Is there a way I can get them to fit.
Thanks in advance.

Below is a picture of the gasket on my 273 head. This is how the TTi header would fit.
It would probably leak.
 
Oh boy. I'm not sure if there's an affordable answer. If you weld on the header flange the coating will be damaged. If you built a set of 360 heads I believe you'd have to notch the top of the bore for valve clearance. Maybe sell those headers and buy the set for a 273.
 
I did a install of the TTI shorty headers on a 273 awhile back.I bought the correct part number for the 273/318 small port. You can weld them up. A good tig welder should be able to do it with no or little heat damage to the chrome pipe as most of the heat will be at the thick flange area. That's about all you can do at this point.
 
Darter6 said:
I did a install of the TTI shorty headers on a 273 awhile back.I bought the correct part number for the 273/318 small port. You can weld them up. A good tig welder should be able to do it with no or little heat damage to the chrome pipe as most of the heat will be at the thick flange area. That's about all you can do at this point.
Click to expand...
I’ve an engineering company, I think your right.
Mig them up on the bottom - then grind them up.
Thanks for the message.
 
brian6pac said:
Get a set of 273 318 gaskets and see how they fit.
Click to expand...
Hi Brian the new header is exactly the same profile as the gasket, I think they might leak on the bottom corners.
Looks like I might have to tig weld them up and keep the heat to a minimum.
Then fit the 273 318 gaskets.
Thanks for your message.
 
I port matched my stock cylinder heads to the 340 gasket with a Dremel tool. I was using Cyclone Headers at the time. I did the same thing to the intake side to match the Edelbrock Tarantula TM-5. I am not recommending this, but that is what I remember doing.

Edit;
But the question is: Did I use the 273 exhaust gaskets or the 340 gaskets to match the ports, that I don't know (this was circa 1973). I am sure of one thing, no leaks.

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I think the best option is to Ni-Rod weld a little extra metal around the bottom of the exhaust flanges and grind smooth. Looks like a few short puddles would do it.
 
Another recommendation. Ditch the tti gaskets and order up some REMFLEX gaskets. They seal up amazing. Plenty of positive reviews on FABO.
 
Garrett Ellison said:
I think the best option is to Ni-Rod weld a little extra metal around the bottom of the exhaust flanges and grind smooth. Looks like a few short puddles would do it.
Click to expand...
Hi Garret
I’m going to just weld them a little and see how they come out.
I think that’s the answer.
Cheers.
 
dibbons said:
I port matched my stock cylinder heads to the 340 gasket with a Dremel tool. I was using Cyclone Headers at the time. I did the same thing to the intake side to match the Edelbrock Tarantula TM-5. I am not recommending this, but that is what I remember doing.

Edit;
But the question is: Did I use the 273 exhaust gaskets or the 340 gaskets to match the ports, that I don't know (this was circa 1973). I am sure of one thing, no leaks.

View attachment 1715284716
Click to expand...
Thanks for the reply.
Yep your right. Looks like a bit of port matching to do.
 
There are at least two reasons why the larger ports may not seal.
1. Relationship of exhaust ports to the threaded holes for the manifold/header/extractor fasteners varies from head to head.
To account for that variation mass produced headers have oversize or elongated mounting holes in the flanges.
2. TTI and several others don't use the flange surface for the sealing. Instead they run a raised bead around each port. That's easier and cheaper than grinding flanges flat. It also means there is yet more variation possible.

Its going to be time consuming but worthwhile to do a mockup using a transfer marker. The coloured 'grease' used for checking gear contact might work. Carbon paper might also work.
If you do decide to fill in the flanges, try to do the most on the bottom and the least on the top.

upload_2019-2-3_12-42-7.png
 
Mattax said:
There are at least two reasons why the larger ports may not seal.
1. Relationship of exhaust ports to the threaded holes for the manifold/header/extractor fasteners varies from head to head.
To account for that variation mass produced headers have oversize or elongated mounting holes in the flanges.
2. TTI and several others don't use the flange surface for the sealing. Instead they run a raised bead around each port. That's easier and cheaper than grinding flanges flat. It also means there is yet more variation possible.

Its going to be time consuming but worthwhile to do a mockup using a transfer marker. The coloured 'grease' used for checking gear contact might work. Carbon paper might also work.
If you do decide to fill in the flanges, try to do the most on the bottom and the least on the top.

View attachment 1715284761
Click to expand...

Hi Mattax
Thank you for your in-depth reply.
I have my own engineering company in the uk.
Ive been in business for 31 years.
Your right these header dimensions for fitting might be slightly different to my heads.
I’m just going to draw the heads and the new headers on AutoCad.
From this I will see how much weld I will need to put on.
I would be able to get a good match when welding and dressing.
I will have to be careful with the heat so nothing starts to bend.
I will put a straight edge along the headers afterwards to see if they are flat.
At least I can do the job and use them.
Regards
This is my first post on this site.
You people are so helpful.
 
Check fit in the vehicle before getting too far into the project.
Assuming this is a LHD car, the driver's side (left) may have some issues with shift linkage, and around brake line and T-bars.
 
EZ, just run a 1/8 mounting plate with 273 port sizes. It will give the 340 header O-ring flange something to seat on. Much easier than welding, just use a 273 gasket as a template and use a jig saw or plasma cutter. the Cyclones were built before 68 so their ports are 273 sized. will need 2 gaskets per side. I had the same port mismatch on a set of Hookers : 340 head ports on a 318 header flange and the entire bottom was unsupported..didn't help that the mounting holes were drilled too high...Hooker asked for a receipt (refused help when I could not come up with a 4 year old $550 receipt) when I mailed them the gasket showing them the port mismatch due to holes being mis drilled. How's that for a lifetime warranty on manufacture defects?
 
67 Barracuda uk said:
Hi Mattax
Thank you for your in-depth reply.
I have my own engineering company in the uk.
Ive been in business for 31 years.
Your right these header dimensions for fitting might be slightly different to my heads.
I’m just going to draw the heads and the new headers on AutoCad.
From this I will see how much weld I will need to put on.
I would be able to get a good match when welding and dressing.
I will have to be careful with the heat so nothing starts to bend.
I will put a straight edge along the headers afterwards to see if they are flat.
At least I can do the job and use them.
Regards
This is my first post on this site.
You people are so helpful.
Click to expand...
We never came up with a good reason why there was so much tolerance allowed from head to head. All I can say is we were not the first to see this. For whatever reason Chrysler apparently didn't see the need to hold a close relationship from the mounting bolt pattern to the port openings. You'll find this to some degree on the intake side as well.

If you have the capacity to machine the flanges flat IMO you'll be far ahead of the game in terms of sealing. And if they are actually straight and flat you can cut away the excess flange between center ports and the ends. I wouldn't do that with TTIs normally because the centers help pull the ends flat, or flatter anyway.

PS. If you do need to recoat - look into Zircotech on your side of the pond for several nice zirconiumdioxide options.
 
Mattax said:
Check fit in the vehicle before getting too far into the project.
Assuming this is a LHD car, the driver's side (left) may have some issues with shift linkage, and around brake line and T-bars.
Click to expand...
Good idea.
I will get under and check.
Best to before doing loads of work.
Imagine getting them re ported then finding out they done fit
 
pishta said:
EZ, just run a 1/8 mounting plate with 273 port sizes. It will give the 340 header O-ring flange something to seat on. Much easier than welding, just use a 273 gasket as a template and use a jig saw or plasma cutter. the Cyclones were built before 68 so their ports are 273 sized. will need 2 gaskets per side. I had the same port mismatch on a set of Hookers : 340 head ports on a 318 header flange and the entire bottom was unsupported..didn't help that the mounting holes were drilled too high...Hooker asked for a receipt (refused help when I could not come up with a 4 year old $550 receipt) when I mailed them the gasket showing them the port mismatch due to holes being mis drilled. How's that for a lifetime warranty on manufacture defects?
Click to expand...
Great lifetime warranty that was.
Yep that’s a good way of doing it.
I deal with a company who do laser cut profiles.
If I send them a AutoCad drawing they will cut them out of 1/8 for me.
Thanks.
 
pishta said:
EZ, just run a 1/8 mounting plate with 273 port sizes.
Click to expand...
I haven't seen the current version but in my experience sadly there is no room to do this.
I don't think its been changed that much if at all. But I was an early guinea pig.

You can see how close it come to the rail here.
There still needs to be room for the head pipe to make the turn which also has to clear the t-bar.
upload_2019-2-3_13-14-8.png


This gives some idea of the room to t-bar.
upload_2019-2-3_13-15-33.png


Again the design may have been slightly changed since then, and my car just may be 'special'.
 
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