Hind sight is always 20/20. It would have been a good idea to put the Two-Liter cams into the 2300 Rio's head and spin them to be sure that they cleared all obstacles and turned freely. Don just said he faced challenges with his engine and that happens when you are an engine pioneer. How would or do the RJR cams work in the Two-Liter head?
I am thankful that Franco offers so many quality reproduction parts to the Alfa community.
I am also thankful that RJR offers his knowledge and experience to the Alfa community.
If I need cams I like having options...
I discovered a few of the differences between the unknown-in-the-US FNM head and the relatively well known 102/2000. There may be more. Pioneering brings unexpected new knowledge, doesn't it?
For instance, I can't tell you whether the port shapes and diameters are identical. The 102 head was derived from the 1900. Some of the 1900's used a single carb, and some used two 2-barrel carbs. My suspicion is that the 102 head simply used the basic 1900 molds, and did what they did to put it into the 102 chassis with the PHHs. But, I fully acknowledge that assumptions can create unfortunate surprises.
The first FNM 2000s started out as identical to the sedan version of the 102. Then, they increased the stroke to 2150cc, then bored that (via changing to wet sleeves) to get 2300 cc. Thus, I suspect (there is that word again) that the FNM port shape, valve seat configuration, and other elements are mostly the same as the 2000. I know that the FNM 2300 dropped the tappet diameter back down to use 105 buckets. This was probably just a cost-containment move. They continued using 10mm valve stems, but have a 9mm collett area allowing the use of modern 9mm shims.
The bearing journals for the 1900, 2000, and 2300 are the same. All of the gears, adjusters, etc are the same for the 2000 and 2300. The FNM made some changes at the rear of the head, resulting in the cams needing to be shorter. This is the least concerning of the issues. The 102 and FNM cams can be used in the opposite head, so long as the adjustments are made to allow it. For instance, the 102 and FNM intake cams have different lengths, so one must use the distributor drive gear intended for that cam.
This thread is about the 1900 and making improved cams available. I like the results of the cams that Richard specified. It suits my use of the car. Very, very driveable around town, but a bunch more torque and a much flatter torque band across a wider range of RPMs, resulting in a nice improvement at highway speeds.
If the ports are much the same as the FNM/2000, I can't see why the same cams wouldn't work in a 1900. I mentioned the different carbs used on 1900s, as that may change Richard's recommendations, but one should contact him directly, if interested.
The issue of tappet diameter favors the 102/1900 head, in that greater lift and a wider lobe can be used, if desired. Again, contact Richard for guidance. I know next to nothing about the 1900 threaded-valve clearance adjusting system, so also don't know what, if any, limits this might pose on increased lift.
Richard specified, I think, 104 degree lobe centers for my cams. Don't quote me on that. I've got the documentation buried in my files. I assembled my RJR cams with the stock lobe centers to get the car working. Richard posted once that changing to 104 would deliver more improvement. At some point I'll go back in and confirm my centers, and try 104, if that's not what they already are. There are other priorities in my life at the moment.