ok i have been staring at the screen for about 2 hours over this vortec head swap...
i did a search and havent found out exactly what i need...
lets keep it simple ... i have a 305 that needs new heads(because the stock ones suck!!)
i would like the L31 heads from what i have read these are the ones to get...??? corect me if i am wrong.
the onlt problem is the comp. so i go to my buddy to have them milled down a little to raise comp.
will the lt1 cam work with the valves and hight in the new head and keep me from wacking a piston?
also now that the heads are milled down when i go to bolt my vortec 4bbl carb intake on will the holes be off because i shortened the heads up? will i have to grind the intake down to match the new head hight?
???????? help me ahhhhhhhh!!!!!
any help will be much apreciated!!

 

ps. i pm'd that guy from that goingslower.com site and havent heard from him yet. there is supposedly a 325 hp 305 using vortecs that are milled but i would like to know about any intake manifold problems he had???
also since i have a 92 will the heads bolt right on. other than the milling.

 

The 325 hp 305 had their Vortecs milled .040" and used the FPP 1094 head gasket which is .017" compressed thickness. Mine are milled .020 and Im using the same head gasket. You wont have to match anything unless you want to, although my intake-gasket-heads were pretty much matched. No piston slap issues. The LT1 cam is just about the most the stock vortec heads can handle, if you want a cheap spring upgrade get the "Z28" spring for insurance. They're only $40 or something. If you have any quesitons pm me or throw them on the board, we'll answer

 

so you are saying when you mill the heads down it won't affect the holes where the heads bolt up?

 

Nah, the bolt holes are fine. You're talking about a very miniscule amount of change in the physical makeup of the heads, but it affects the overall area of the combustion chamber just because you're taking out the widest part, thus removing the most area. However, the heads change minisculely (sp? Is that even a word? lol!)

 

intresting...

 

If you exceed .030" on the milling you really need to have the intake machined to match. Also, make sure and use a Vortec intake with Vortec heads.

 

When the heads are milled get them to machine the heads intake surface also, that will keep the holes aligned properly when the intake is bolted on, that keeps you from having a bastard intake that won't fit anything else.

 

hey also i found the vortecs on jegs for 249.00 a piece with everything but rockers... the guy said they could handle a .550 lift. the stock vortec that was in my chevy mag said it would only take like a .430 or so... so does this mean jegs put better springs in??? or is the magazine off a little on there numbers? i think it was super chevy mag... talking about vortec heads... "vortec chronocles"

 

--I'm pretty sure stock vortec's are good to .480

--I'm not positive at what specific point it becomes necessary, but I took a set of wp s/r's down to 58 cc and had to have the intake milled down to sit flush in the valley and bolt up . . . I want to say that however much comes off the head, half that has to come off intake, but it's been a while, and I'm sure your machine shop will know . . . ask beforehand cause I was ready to slap on intake oh wait a minute this beotch won't go on, let's make a trip to machine shop. throws a kink in your plans for sure . . .