I have seen a lot of folks lately post in regards to cams in general, cams for TF heads, and TF heads.
I know folks are trying to be helpful, but most stuff I have seen is largely in accurate.
These are all very large subjects, I'll be brief on them.
Cams, Bullet cams are not the magic answer to TF heads. A cam company has some general shelf grinds, and outside of that there going to produce what the engine builder request. It takes extensive knowledge to recommend and or come up with cam designs. This is definitely not the novice, or mid level folks even. You must understand each aspect of the cam and what's effect on engine behavior are. There are many factors that dictate the necessity of varying cam grind specs. You don't learn this stuff in day....
TF heads, flat out a better casting then a PI, but must be employed correctly. Wont go down the road of why its better as its been beat to death.
There factory valve train components, they will work if set correctly, but have a limit. You must understand why the failures occur. What TF uses is a 21-2N Stainless Steel. Its not terrible and if treated correctly is a solid mid grade performer. The main problem is the valve cut at the base of the stem as the it transitions to the valve head, the diameter is reduced here when there cut. That's why they will tulip when they are put in an environment favorable for that to happen. So what is that environment? Excessive seat pressure, to use these valves you want to stay in the 125-130lb seat closed pressure range. So this means no Track Heat pre assembled heads with 150lbs on the seat. That much seat pressure plus a cam with more than .550 lift, throw in some good heat and you have the recipe to tulip one. On top of that throw in a 195cc head where the valve is 1.9 over the 185cc head and you have a larger diameter valve face with the same stem diameter, same cut down stem near the valve head and you have a even higher propensity for tuliping if conditions are met.
So in the name of keeping this short, if you want to use a preassembled head, only use 185cc head with a there 125lb springs, they will work fine. As always, the build must be correctly done with good tuning as well. This are fine for mid level builds.
If you to work a 185cc head, then start bare using the correct component, which will get too.
Before getting to the 195cc head, the question is which one do I use? On a standard bore to .030 over the 185cc runner is actually better suited base on displacement. You have to consider velocity, and airflow in to the cylinder. There will always be trade offs when deciding what to pick, but the goal and purpose of your engine will dictate your purchase.
Can you use the 195cc cylinder head on iron block? Yes, must be a minimum of .020 over. This does not mean that it will work well. Just that it can fiscally be done. If someone wants to utilize them in this situation I only recommend it be done on a .030 over block with it notched for the intake valves. Otherwise you will crush the flow and velocity into the cylinder. These heads really shine on the bigger bore 5.8L engines and really take advantage of the larger valve.
In my opinion, if your using 195cc heads your probably building a high HP engine. Always start with a bare head. You will want 130-150lbs on the seat closed. Spring choice and install height will dictate final pressure. A severe duty valve on the intake, and a Inconel valve on the exhaust. An iron or bronze guide will be suitable here but knowing intent of the engine may dictate a particular choice. These heads come with a 1.9 intake, and a 1.47 exhaust valve. Depending on goals the exhaust side will altered.
I have only scratched the surface here, but this may help guide someone in there choice.
