I am still trying to figure out what my Winter plans might be but my latest thought is to do a complete head swap with a roller rocker setup.
I might have an opportunity to buy a complete set of heads (ported, roller rockers, springs: no details yet but they are from an engine builder that is done testing them and wants to sell). They would be a direct bolt on to my existing J heads.

I am curious what kind of gains that could be made from swapping heads and keeping my existing cam. The cam swap would become a future upgrade if the money goes to these heads. The person that the heads are coming from is the same person that I have been discussing getting a roller cam from and he knows that these heads can support the cam swap. I just wont have the money to do both the cam and the heads at the same time.

If the heads have the potential of being used with a larger roller cam, would the short term of getting these heads and bolting them on my existing motor, would there be more gains than losses? Once again, I do not have the details on the heads yet, but I just want some advice before the offer is made.
I was told that the set of heads have testing time and they would be complete. This person was just letting me know that they might be for sale and he just wanted to see if I was interested or not since we have been discussing me getting the cam/rockers/porting my existing heads over the Winter.

My worries: My current cam is fairly small (see below) and my current heads are stockish built 2.02" J heads with a bowl blend and Comp #901 springs (apx .500" lift).
My goals: I am planning on upgrading my 340 by buying roller rockers, new cam, and sending the heads to the shop to have them reworked for the roller cam (lifters/springs/porting).

Due to money, I was planning on buying the rockers (1.6) this Winter (+ springs to give my current cam a little more lift while upgrading the valve trane) and then later buying the cam and having the heads done. But this opportunity might have me changing the direction a little bit. If I can buy the heads, I might have to drive the car with the existing cam for a while before upgrading to a roller cam.

Would I see much of a gain with just the head swap and no cam swap (until later) on a street car? The builder told me that the price would be a wash as if I was to bring in my existing heads and let him port them and add the rockers and springs. This way I would have an extra set of good running heads.

Thanks