billybonesmusic

here is a question, do the newer vortech heads with 1.94 valves make more power and flow better than the 041 casting heads from a 68 z28 with 2.02 valves? (both 64cc comp) also, my machinest said he can "pin" the rocker studs so they wont walk out instead of threading them, i guess i can trust him? what do you think? dont think he wants to work too hard LOL.

tjwong

Actually according to GM the new Vortec heads out of the box flows better than their old venerable Bowtie heads. So I would think that unless your old 041 heads flows better than the Bowtie technology of yesterday that the new Vortec heads will out perform them. As far as pinning, I haven't heard of anyone doing that. I would just step up and have him convert it to screw in studs, the expense isn't worth the greif of what a ripped out stud will cause. Especially if you are going to use a roller cam requiring stiff spring loads.

billybonesmusic

THANKS, I believe you are right, i just have like $500 invested in these heads, they would be great for an older car that has to have em, maybe ill put them for sale here, as for the pin, he seemed like no big deal, they wont come out with a hardened pin, but......like you i would feel much better inside if they were done right, sometimes i need a kick in the pants reality check. he he

rklessdriver

The Vortecs out flow the 041 castings even with the smaller 1.94 intake valve by about 15-25cfm across the board (041's came with either 1.94/1.50 or 2.02/1.60 valves). Every set of Vortecs I have had on our bench flow in the 240/160 range @.500lift. I have cheated them up (for limited class oval track racing) with a bowl cutting tool I made to flow in the 260/165 range. The old phase 6 Bowties were in the 220/130 range @.500 out of the box (2.02/1.60 valves) and any of the prouduction 461,462,040,041 casting heads struggle to equal the old Bowtie's numbers cheated up with a real good valve job and big valves, (no hand porting). I could dig up some actual full across the board flow numbers from our testing with various prouduction heads over the years if you wanted.

You will still have to mill, drill and tap Vortecs for screw in studs & guide plates or you can buy them from one of the oval track suppliers already done up for like $550.00 complete.

DO NOT EVER pin pressed in studs. I know they did it back in the 1950's and all that but that roll pin can break. Then they crack off about half of the stud boss with it and then you can't even mill it flat, drill and tap it for a screw in stud.
Will

billybonesmusic

awesome info, thanx.

RWDsmoke

I'm very happy with my vortec heads. I used screw in studs, valve guides shortened for more lift, and valve spring pockets enlarged for bigger springs. After much data logging, I found they are very happy with 87 octane gas. And it pulls hard from 1200 to 6k rpm's.