I am going to be putting the LPE 74216 cam in my 305 roller and Tim Dyer form LPE recommended to use the LT4 springs with it. They have a recommended max lift of .525 and the cam is going to be used with 1.6RR with a max lift of .501.
My question is, the springs have an installed height of 1.78" and the factory springs have an installed height of about 1.72" Int / 1.59" Exh. Will standard lenght valves work and will some machining must be done to the spring seats to accomodate the LT4 springs? If machining is done then will I need shims to get the correct height?

-Ozzy

 

Yes you will have to machine the seats down at least .060", or use longer valves, or use some good quality springs instead of those stock ones. On the exhaust side, removing the "rotator" thing will add about .100" of installed height; but you'll still be short of what you need.

If you have to buy valves anyway, get .100" long ones. Then you will probably have enough clearance to set the installed height correctly using shims without machining. In that case, expect to need .100" long push rods as well.

 

Thanks RB, sounds like a good idea, I'll have to remember that when I take them to the machine shop. I haven't ordered the valves and pushrods yet, I wanted to get an opinion first. I decided on buying the LT4 springs since my car is not really a strip car. I know the benefits of double springs and all that but these suit my application.

-Ozzy

 

It looks like the spring seats are going to get machined down anyways because I could not find the longer 1.94 intake valves. I ordered the Manley Race-Flo 1.94 and 1.50 valves from Summit.
Now how about the pushrods, do I have to wait until I get everything together to check the lenght and buy what I need or should I buy stock lenght ones now? Is it a safe bet that I will just need the stock lenght pushrods?

-Ozzy

 

Yes you need to wait.

You need an adjustable push rod, such as this one. http://store.summitracing.com/partde...CCA%2D7702%2D1

No it is absolutely not safe to guess at the correct push rod length.

 

Sounds good, thanks for the help.

Ozzy