I am looking for an aftermarket header and exhaust and am having no luck finding anything. Anyone have any ideas?

 

The concensus is that headers make very little difference on these engines, an exhaust MIGHT get you a couple of horsepower.
Best bang for buck is a cam swap, but if you really want headers, there was an Australian company making them:
Volvo 240 Series 4cyl Extractor | eBay

 

I want the exhaust because mine has many leaks, but I might just have a nearby shop run me a 2 1/2 out from the cat. What kind of power can you get from changing the cam>

 

I also read your blog on e85 and such. Now I am wondering how hard it would be to turbo my car since it did not come factory turbo?

 

Depends on the cam. The H cam was Volvo's most aggressive n/a cam...you might get 140hp. The K is more common and good for maybe 132-135. It takes big bucks to make an n/a tractor motor a performer. Much cheaper and simpler to swap in a late model turbo motor. In the US, it's almost guaranteed your 90 GL is a Regina injection system...makes it a bit more of a challenge to turbo. Turbo cars used Bosch LH injection...
To make your motor a performer, you'd need to swap in bigger valves, z deck the block, possibly mill the head, swap in lightweight rods and pistons...lots of money and work to get maybe 165-175hp.

 

yeah its the regina system the seller told me that t was important for me to know that. I dont care about blowing people away but Id like to pick up some power to get this sled around a little better. But in my area its hard to find parts or people who know much about volvos period much less where to find parts.

 

I just so happen to have a 90 740GL. My solution to the lack of power was pretty simple.
https://volvoforums.com/forum/volvo-...47/#post214428

 

thats definitely a solution but I am not so sure about the simple part.