Is this the elbow you are referring to?
Diesel
If it is, I have no experience with their elbows, but I do have a set of their custom headers on my 1982 F100. I know the header guy (possibly owner??) there is George Klass. He is a stand up guy that cares more about the customer than making a profit. Example, my headers are 2" primaries with 3.5" collectors. I was told by a lot of people that I need 1, if not a 2 step header. The 1 step would've added $99 to the cost and the 2 step would've added another $199 on top of the $99 for the first step. When I called George to ask him about it, he said right away that it wasn't worth the money. In my application, it wouldn't be necessary.
In my opinion, that is huge when you are dealing with the main guy at a company and he turns your money down. He works very closely with you on your build and cares about how it fits and functions after the sale.
The headers are fully hand made and tig welded. Very heavy duty. Also, a lot of the Ford Lightning and late model Mustang guys run the Accufab throttle bodies and have very good luck with them and have good performance gains with his stuff.
So, back on topic. If his elbows are anything like his headers are, I'm sure they are top of the line and you won't be disappointed. If ya want, give George a ring and he'll answer any questions you have and won't give ya an B.S. just to sell a product.