Opel GT Forum banner

Will a Manta Exhaust Header Fit a GT?

6262 Views 25 Replies 14 Participants Last post by  rangerrick
gt exhaust header

hey everyone, could anyone tell me if a header that is made for a manta will fit on a gt? i need a header!!! :mad: the one that was on my gt when i got it fell apart... and i havn't even got it driving yet.... :(
1 - 20 of 26 Posts
If your talking about the 2 that are on Ebay right now, it doesn't appear that they will. there are different motor mounts for the GT and Manta. I do like the 7 cylinder exhaust gasket that is pictured.
yup those are what i was thinking of... well thats not cool. :cool: do you know if OGTS has any headers, i just got myself a catalog from there but it says they are discontinued... any advice would surely be welcomed

I just read somewhere that Opel GT Source is going to have headers for sale again. You could email them and ask them for sure.
The headers for sale on eBay are for the Manta/Ascona (aka "1900") only. The down-comer drops pretty much straight down, which would probably interfere with the GT engine cross member.

Now, that said, I am thinking of buying one and using it in my '75 Sportwagon that has EFI. Then I could use the '75 Sprint manifold on my GT. Does anyone have an opinion as to how "decent" these headers are. I see that they are the unequal length style, so they won't flow as well as the Sprint. But my SportWagon is hardly a performance machine! I am going to ask the seller who the manufacturer is and ask a few details about their construction, and I will report back if anyone is interested in the second header (I have dibs on the first!)
Manta Header?

I bought one of the headers on eBay hoping that it will fit a GT. I don't know for sure if it will work but I hope so. It looks nice.
Trent Petrie
I haven't heard back from the vendor yet. Does anyone have photos of a Manta/Ascona header versus a GT header? I seem to recall seeing photos of both, with the Manta header more "upright", and the GT header more "swept" to the rear. But I can't seem to find them. Maybe it was on eBay a while ago?
Here is a Tri-y and a four into one GT header


See less See more
Manta vs. GT headers

If memory serves, Pacesetter had different P/N's for the Manta/1900 and GT headers, the main difference being that the downpipes were more angled on the GT header as already mentioned here previously.

BTW, you can't install the 4-into-1 Pacesetter GT header without removing the engine cradle . . . it's that tight!

the headers that i have to replace are connected like the 4 into 1 pipes and has that bar thing, but they are positioned more like the tri-y... just with the middle 2 pipes being on the inside and closer to the engine. when i took them off i had to remove the valve cover and wiggle it sideways... it was a mess ;) what do you guys suppose they are then, some auto shop remake or something?
If the plate that goes against the head ("header plate") is sound and the correct thickness (same thickness as the intake manifold where the mounting bolts go) then any half way competent muffler shop with a computerised pipe bender should be able to reproduce individual pipes the same as those on the existing header pipes and replace then one at a time to keep the shape correct. The operators of those pipe benders can sometimes do miracles for far less than the cost of another new unit. Have a look around locally and ask the Hot Rod, Circle Track and/or Rice Boys in the area who is best at making up custom exhausts.
petrieopel said:
I bought one of the headers on eBay hoping that it will fit a GT. I don't know for sure if it will work but I hope so. It looks nice.
Trent Petrie
Have you tried that header yet?
How do they look, and will they fit a GT? How thick is the flange? Will it fit up to the stock intake manifold?

I had bid on a Sprint Manifold, but lost it this morning. $150 was my limit. The header vendor has another set for sale (first bid $99.95, Buy It Now for $139, so he has raised his price), which would go into the SportWagon, and it's Sprint into the GT. But if it fits the GT, then in it goes. Or, if you can't use the one you bought in your GT, I would buy it from you for the SportWagon.

The header that I got from Ebay is one that Pacesetter use to sell. The flange is the same thickness as the Sprint exhaust manifold. I haven't installed it yet but I quickly put it up against a spare engine and it appears to fit great. It is much lighter than the Sprint. I'm happy with it.
Thanks, Trent
Can someone link me to more info on the Sprint manifold? I am also looking for GT headers and wondering if this would be a good option. :)
NO link needed.. What is needed is the exhaust manifold off a 1975' Manta or Ascona.

What are the benefits to going with a different manifold or headers. I know the performance / flow should increase with headers, but what I am wondering is, will it keep the engine or intake any cooler?
Headers/Sprint exhaust

The flow may be increased with a Sprint manifold or with a header. Probably not as much as you'd think, but some, over the 71-73 cast iron GT/Manta exhaust manifold. As Bob Legere has explained before, it not the exhaust on the Opels that's the problem. They usually flow well. The intake side of the equation is the problem. Anyway, you won't notice a "cooling" improvement with the header or the Sprint manifold, unless you wrap the header in insulating tape or have the Sprint manifold ceramic coated. That might increase the thermal efficiency of the manifold slightly, but it would sure reduce the heat on the passengers side of the engine bay. Anyway, that's something to think about.

The Pacesetter header will ne fit the GT unless it is the correct part number. In face no Manta header will fit the GT due to the bend in the pipes. The Pacesetter is not the preferred header, the Hooker is, but it is scarce. Enlarging the exhaust pipe to 2" ID from the lead pipe joint out to the resonator through a larger center muffler is nearly as effective and much less work. Should be about $100-150 or less at a good muffler shop. Also, less time and less invasive.

Good luck.

See less See more
Reference 1975 Manta.

Does the length of the exhaust pipe -- from the collector at the header/manifold to end of the tail pipe -- affect flow/performance? I plan to keep the exhaust piping on the passenger side of the vehicle -- connecting at the collector with a 2" - 2.25" pipe to a flow-thru muffler and end it just in front of the rear jack point -- a "Shorty."

Additional information:
This is NOT a street car.
Weber carb is used in place of FI.
Header (pipes lengthened 10") used in interest of less weight.
Fuel lines (steel braided) are on the driver's side .. ala GT .. but cross over to the carb at the rear of the engine. Thus routed totally away from heat sources.

Thanks for you comments

See less See more
svopel said:
Does the length of the exhaust pipe -- from the collector at the header/manifold to end of the tail pipe -- affect flow/performance?
Absolutely. A shorter pipe will favor higher rpm power at the expense of torque.
1 - 20 of 26 Posts
This is an older thread, you may not receive a response, and could be reviving an old thread. Please consider creating a new thread.