I finally am beginning on my 355 ! (only after a year of looking at the stripped block lying in the garage). I need some help buying parts for heads. I know that i want the vortec L31's. But they dont come assembled, so i am a bit unsure of what valves and springs to buy.
I am planning on running the comp cams XE274H cam with .49 int / .49 ex. with 1.5 roller tip rockers. and 4 valve relief hyper flattops.
Any help would be greatly appreciated for i dont know the formulas or combos for guide clearance issues/ piston to valve clearances and many of you know what you know what will work and what wont.
Thanks,
-Bob

 

If your stuck on Vortec, i would get the performance upgraded versions. They come preassembled with better springs and the necessary machine work to run more then .460" lift.

But if you want to match the springs to the cam which is advisable. Get the springs comp recommends for the XE274 and have the heads machined to take the higher lift and springs.

I would also suggest you do a search on this board to find out more information. THis comes up about 20 times a week.

 

Thank you, i guess i will have to search under different terms then since i have not found exactly what i have been looking for.

 

I would also look into the PRO 906 vortec heads. They are far better then the stock GM castings and cost about the same. They are even cheaper then the GM castings when you factor in the machine work required to run them.

 

I searched for this post by my dad and found it for you:

https://www.thirdgen.org/techbb2/sho...threadid=47463

 

Competition products/ Pro topline vortec heads.

Pro Topline head assemlies. 64cc combustion chambers, 170cc intake runners, hardened exhaust seats for use with unleaded fuel, improved water flow for greater thermal efficiency and a thicker deck to resist cracking. Blueprinted assemblies with stainless steel valves, LT-1 valve springs, seals, chromemoly retainers and 3/8 screw in studs.
Price: $499.95

These heads are said to be good for .510" lift.