NEWER vortec heads require different valve covers that the traditional first gen SBC but there are adapters available to sallow their use, but they cost almost as much or more than many valve covers themselveshey grumpy, I ran into a few issues with my swap to vortec heads ,
http://www.jegs.com/i/Patriot-Performan ... Id=1192214
I thought I post these flow numbers on ported vortec heads ive seen posted , just in case anyone has ever wondered or wanted to know the flow numbers a set of stock vortecs. I was also curious if any of you have any guesses on what gains I picked up on the port work.
INTAKE LIFT------- STOCK---- PORTED-- GAIN
.1---------- 59--------- 64--------- +5
.2---------- 117------- 132------- +15
.3---------- 170------- 187------- +17
.4---------- 214------- 236------- +22
.5---------- 226------- 255------- +29
.6---------- 219------- 259------- +40
EXHAUST
LIFT STOCK PORTED GAIN
.1---------- 42----------46--------- +4
.2---------- 83----------90--------- +7
.3---------- 123--------139--------+16
.4---------- 136--------161--------+25
.5---------- 143--------174--------+31
.6-----------147------- 178--------+31
the Difficulty I ran across were all related to the standard original intake manifold from edelbrock. I am running a edelbrock vortec manifold and I had to oblong the mounting holes. I was warned about this by patriot when I asked them for install tips on their new vortec heads
http://www.jegs.com/i/JEGS+Performance+ ... 0/10002/-1
Ive seen intakes that failed to seal on the lower intake port gasket,because the cylinder head matching surface was not at the factory angle,so no factory angle intake manifold seals correctly, that area can be rather thin on ported intakes and the wrong gasket can make it impossible to seal, and allow air to enter the intake ports via the lifter gallery, especially if the heads were milled previously, but you need a consistent 5 psi of fuel pressure at the carb inlet port, to allow most carbs to operate correctly, and Id also check to see if your vacuum connections leak, a leaking brake booster for an example
keep in mind the intake manifold bolt angles and port shapes and locations are very slightly changed and are different on vortec heads , than on standard heads and some aftermarket heads, and some aftermarket intake manifolds, are designed as a compromise that in theory can be used in either application, but like many compromises thats not always 100% true
