<VV> Turbo Advise?

[Bruce Johannesson]

Hello All,


A few months ago, I was seeking some advise on a '65 turbo engine that I am installing in a '66 coupe.  I've finally had chance to get the engine out of the donor car and disassembled.  


The engine is an original '65 turbo with a set of 140 heads.  The heads appear to have been on the car a very long time, possibly for all of the engine's 50,000 mile life.  Someone has done a nice job of opening up the combustion chambers to reduce the compression ratio.  (Originally, this was listed as a concern by others)  The heads are carboned up with fluffy black soot, but don't have any significant hard deposits. The chambers look good, no evidence of melting or other damage.  I haven't verified the actual volume of the combustion chambers, but for the sake of argument, let's assume that they are the same as the regular turbo heads. 


The engine has a Isky 280 cam.  The lobes and lifters look pretty good so I'm definitely going to re-use it.  


The car also came with the original set of turbo heads.  They look almost brand new.  I would be surprised if they had any significant mileage on them.  My suspicion is that they were removed from the car when it was brand new.  


My questions are:


1.  Would there be a significant advantage to using the 140 heads over the turbo because of their bigger valves? 
2.  If the 140 heads are used, would it be advisable to swap out the exhaust manifolds to the turbo version?
3.  Are there other disadvantages to using the 140 heads over the stock turbo heads (i.e. cooling, etc.)
4.  Does anyone have dyno experience with the Isky 280 cam?
5.  Should I remove the bottom engine shrouds for better cooling on the Turbo?  I read somewhere that it might help.


Also, just kidding on Question 5.  I am finding out that Corvair owners are a passionate bunch.  I enjoy reading all of the posts on VV and I count myself very fortunate to be among your ranks!


Thanks in advance.


CC