Vortec Cylinder head and cam questions - Third Generation F-Body Message Boards

THETANK · 06-06-2009, 02:24 PM

I have posted a few times regarding my motor swap that I will be doing hopefully by the end of the summer. I currently have a L03 TBI and will switching to a carbed motor. I have a few questions that have popped up since I have been reading about different cams heads etc.. I will be starting with a crate L31 (pn 12530282) 9.4 :1 CR. I will be removing the stock vortec heads that come on the motor and replace them with patriot performance vortec heads ( as they seem to flow a little better , have better springs which accomadate .575" of lift and better valves on them as well and will only cost me about $100 additional after I sell the stock vortecs). I am looking at putting on an Edelbrock Performer RPM manifold or Edelbrock EPS manifold. I will be using a GMPP distributor same one that comes on the ZZ4 crate motor. I am unsure which carb I will be going with. Now to my questions:

1) Will the Patriot Vortec heads bolt directly in place of the stock vortecs with no modification?
2) I am looking at several different cams and trying to decide which to go with. I am considering the following:
Comp Cams
a) XR276 224/230 .502/.510 lobe center angel 110
b) XR270 218/224 .495/.502 lobe center angel 110
c) LT4 Hot Cam

3) Which brings me to my last question I saw on the Comp Cams website and on their cam selector I downloaded the following installation notes:
[7] Stock springs cannot be used.

[15] 50-State legal on ‘93 & earlier S.B. Chevrolet V8, 262-400 c.i., C.A.R.B. E.O. #D-279-4.

[11] Lifters only, does not include lifter retainers or guides.

[2] Requires machining on cylinder heads.

[3] Valve spring oil shield available.

Does this mean that the valve spring on the modified patriot heads will not work? Do you need to use the recomended beehive spring?
Why do the cylinder heads need to be machined to get this cam to work?
I was hoping to get the long block remove the stock vortec heads, simply bolt on the patriot vortecs and the remove the stock cam and install the comp cam without modifiying cylinder heads any further (machining , changing springs etc)

This vehicle will be used soley for street driving cruising events and car shows. Any additional input on this setup is appreciated. I wanto to make sure this engine is streetable but also has a noticable/choppy idle (shooting for 375 - 400 HP and decent low end TQ).

Thanks in advance and sorry for the long post

five7kid · 06-06-2009, 03:10 PM

Comp is talking about GM heads & springs.

You shouldn't have any problem with the Patriot heads. They'll bolt on, use the RPM intake, go for it.