hi-performance single port??

[bamaalan]

Trying to restore my grandma's '77 for my 16 year old. We bought an engine that had been rebuilt by our local "expert", 1600 single port new pistons/jugs,bearings, counter-weight crank,light weight flywheel,bosch 009 w/pertronix ignitor, rabbit carb, and engle race cam. Well the cam broke a valve spring and messed up the guide after about 100 miles. If I replace the head and add double or performance single valve springs would this set up hold up?
Or would I be throwing money away? Would I be better served by swapping to dual port heads? and if I did swap would I still need performance springs? Any help would be greatly appretiated.

[trooperbrett]

Dual ports are a better way to go, I've heard it said that you can do all the cool race ready stuff to the single port heads (port/polish, big valves, etc...) and it still wouldn't flow as good as a stock dual port head. The stock single springs are good up to about 4500 rpm. If you feel the need to go faster, you can get get heavy duty single springs that are good to about 6000 rpm. Anything above that will need dual springs, but with your basically stock engine you shouldn't need them. I've been running a 1776 w/big valve dual port heads with dual Weber IDF's with single springs and have had no problems, I just keep it under 5000 rpm. Also, I don't know for sure but the cam might be way too much for the rest of the engine, was it built for offroad use? There are classes for stock sized engines and maybe you have one of these? If you do I don't know if it would be good for a daily driver or not.