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Discussion Starter #1
Is there a difference between 1600 and 2 ltr manifolds? I'm trying to fit my 4 branch manifold to my new 2 ltr engine and it's tight everywhere, I bought this many years back it was sold as a GTA replica from a reputable Alfa specialist in Germany, it fit fine on the 1600 engine
Any help gratefully received
 

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I’d say, stock manifolds are interchangeable, however if it’s a true header, I believe the 2 liter is dimensionally taller than a 1600, which could be the cause of the issue.
 

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Yes, the stock cast manifolds are the same height. It's the downpipes that differ. 1300 one height, 1600 another, 1750/2000 are the same/longer still; 69 and earlier 1750 has a squarer curve to get around the pedal box.

Andrew
 

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Is there a difference between 1600 and 2 ltr manifolds? I'm trying to fit my 4 branch manifold to my new 2 ltr engine and it's tight everywhere, I bought this many years back it was sold as a GTA replica from a reputable Alfa specialist in Germany, it fit fine on the 1600 engine
Whoa, hang on. Is this a tubular, welded exhaust manifold (like the photo below), or a two-piece, cast iron manifold?

Upon re-reading your post, it sounds like the former ("GTA replica"). But I think the replies above pertain to non-GTA, two-piece, cast iron manifolds (well, VabeneGTV says tubular headers may be specific to engine height).



I don't have any hands-on experience with repro GTA headers. The photo above came from the Classic Alfa site, and their description for this product says: "Designed to suit 1300 & 1600 GTA engines, but will also work well on 1750 & 2000 engined GT/GTVs and can be adapted to work on Giulia Saloons as well." But I don't know whether Classic Alfa gets their manifolds from the same supplier as your reputable Alfa specialist in Germany.
 

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Discussion Starter #6
That looks very similar to what I have but it's not fitting the 2ltr, if I loosen off the flange bolts it kind of fits but binds up again as I start to tighten the bolts, will persevere but suspect I may need a new header or start cutting and welding, last thing I want is it fitted under stress and something cracking when used
 

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...if I loosen off the flange bolts it kind of fits but binds up again as I start to tighten the bolts,
Just to keep the conversation going: what part of the header binds up on what?

Have you asked the header's supplier if their part fits a 2L? Since all GTA's were 1300's and 1600's, I can picture how a factory header wouldn't accommodate a taller engine.
 

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They look like the IMASAF offering, and I suspect any GTA replica would be this brand, since other vendors do offer header but do not claim them to be replicas, but through the grapevine fit well. In my opinion IMASAF fitment is hit or miss, the rear section I got for my Nuova Super had fitment issues, the stinger from IMASAF fit perfectly. My Euro Alfetta front and center section fit, but was not perfect, but usable. Just my thoughts.
 

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Discussion Starter #10
The top of the pipe as they level off are very close to the floor and the outer down pipe cylinders 1 & 4 catch the lip where the firewall turns into the floor it's also very close to the lower end of the steering box I'm concerned it will cook the lower bearing. I bought this in 1998 and it's been in this car with a 1600 cc engine since then, I would estimate it's an inch higher than it was and this is the problem
 

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Yes, the stock cast manifolds are the same height. It's the downpipes that differ. 1300 one height, 1600 another, 1750/2000 are the same/longer still; 69 and earlier 1750 has a squarer curve to get around the pedal box.

Andrew
Are they the same for RHD cars (no pedal box interference)?
 

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The top of the pipe as they level off are very close to the floor and the outer down pipe cylinders 1 & 4 catch the lip where the firewall turns into the floor ..... I would estimate it's an inch higher than it was and this is the problem
I would also assume that the greater height of the 2L engine is causing the problem.

But the difference in stroke between the 1600 and 2L is only 6.5 mm (82 vs 88.5 mm), which would translate into a difference of just 3.25 mm ( ~ 1/8") between the crankshaft centerline and the block's deck. Are 2L connecting rods longer?

Given that you bought the headers in 1998, I suppose wouldn't make a lot of sense to contact the vendor 22 years later to ask about fit.

As Andrew explains, the downpipes used with the stock headers certainly differ between 1600 and 1750/2L engines, so it would be surprising if tube headers didn't need to have different dimensions as well. I'm puzzled how Classic Alfa's GTA replica headers could fit all Alfa engines, but as I mentioned in post #5, that's what their website says.
 
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