I just purchased some Vortec Fast Burn heads, and i was trying to put together a list of modifications to make to these heads to have them really put out some power.

So far i have:
port/polish
elongate pushrod holes for 1.6 rockers
screw in studs
machine for larger valvesprings

I heard that the power you would gain from opening the valve size up to 2.02 and 1.6 isnt worth the amount of money you would spend on new valves and machine work....is this true?

And is there anything else you guys would recommend to do to these heads?

 

Are they Vortec, or are they Fast Burn?

Fast Burn (12464298) heads already have screw-in studs, and the holes that are already there will acomodate 1.6 rockers AFAIK. Their valves are 2.00" & 1.55"; already so close to the old 2.02" & 1.6" max that there's no sense in spending money on that little bit of improvement. I'd definitely put larger springs on them though, if that's what they are; they come with those weenie LT4 springs, with only about 100 lbs of seat pressure when new.

Tell us which heads you have, and I'm sure you can get better details on what to do.

 

What you heard about installing larger 2.02 vlaves in a stock nonported vortec head is true. You will gain little flow.
Bt... if you're going to port these heads then increasing the valve size will increase flow.

On mine I did a moderate but complete porting job and installed 2.02's and 1.60's
and flow jumped up from 228 cfm to 246+cfm.
I did some mild chamber relieving too.
During flow testing the hi volocity of the air flow into the port kept sucking the inlet radius putty right into the intake port. Made it difficult to get a reading.
We gave up at 246.
The 2.02's alone without porting only brought the flow up to 232cfm.

We did not test the exhaust side.

 

Sorry, they are the Vortec heads.

 

ive got the vortec heads on mine and you dont really want to touch the intake ports except for cleaning the cast marks out....the exhaust ports respond well to some porting, especially around the valve throat and valve guides, and then do the chamber blending around the spark plug outlet.....your gonna love these heads........just my .02