305 rockers

[ssn696]

To go to screw-in rocker studs, you have to remove the heads, pull the studs, machine the pads, drill and tap the heads. 305 head chambers are too small to use with a 350, and big-valve 350 heads will hit the 305 cylinder walls. So, save your pennies and belly up for a crate 350. Best bet: get an 'R' long block with the Vortec heads already on it, plus it's set up for a roller cam. The downside is that it does not have the pushrod hole drilled for a mechanical fuel pump. If you go with fuel injection, this is no problem, but....

Sorry in advance if this is useless advice for you...

 

[ssn696]

To follow up on your original question, 1.6 rockers change the geometry of your valve train. It's important to make sure that your springs and keepers don't bind with the additional travel. I bent 6 pushrods and mangled both heads' pushrod channels after changing a cam on stock heads. After that, I did need guideplates. It was an expensive lesson (time and money)...better spent on a better engine. BTW...Vortec heads will handle up to 0.460 in lift. Any bigger cam, and the spring pockets need reworking, plus springs up to the task.

 

[ssn696]

Just a thought...if you currently have a 4bbl on your 305, Cyber Monday is coming...