I am going to put the cc306 in my car and my friend gave me a set of 983-kit springs, but they look like they are a little to big on the lt4 heads I test fitted them ( not sure of difference in lt4 and lt1) so should I get something else? I really dont want to take heads out of car to machine them.

 

I used the springs from Combination Motorsports. The 612s I believe. They were only $99 bucks too. Call them up and get a set.

 

I used comp cams 987 with matching retainers and 10 degree locks. the spring seated hat to be widened a bit.

 

did the combinations motor sports ones require any machining?

 

I'm using 4771 locators with no machine work - contrary to what I understood before the install.

 

Nope, they are a direct replacement. Talk to Seth or Nick over there and they will be able to answer all your questions.