I just secured a pair of Vortec heads for my 305 L03 engine (TBI)

I know that i need to match it with the proper intake (the egr will be plumbed from the headers) .

When it comes time to install the components, I want it all to be said and done...valves replaced, new springs, seats, ported, new cam, rockers and such.

I plan on taking these 194's to 2.02 intake/1.60 exhaust as well as having the heads ported.

My goal is to maintain streetability. I will be putting in a posi rearend with 3.73 gears.

A friend I bought the heads from says to not go over .500 lift as the the engine couldnt handle it. I need to know a cam that would compliment my goals with how much lift/duration. And i dont know much about cams/intakes/heads.

I hear all this stuff about hypeurectic rockers/hydralic roller/solid rollers and such. I want to maximize the 305's abilities with the vortec head/intake combo. Is taking the valves to 202's worthwhile? any/all info is greatly appreciated.

blain

 

If i recall the vortec heads are 64cc chambers right. If so you would need to have them shaved down a little, to keep compression up.

Are you gonna be using the TBI? you will need a custom chip. and an AFPR

 

i have a chip already, how would that affect where i stand now?

AFPR?

 

well when doing major mods, like you are doing, its not gonna run the same as the motor did before, plus you will always benefit from a custom chip,

AFPR, adjustable fuel pressure regulator, you need to up your psi, a little so it will not run lean.

 

Are the stock 305 heads not 74cc? If they are, wouldnt putting the 64cc vortecs on there already increase compression considerably, so not much need for shaving them down?

 

So far I would need an AFPR, may need to shave the vortecs down a little. What kind of compression am I looking at without shaving them down. Also, what about the cam lift/duration? rockers?

 

The 2.02" valves won't work in a 305. If they don't hit the cylinder wall, then they'll just be seriously shrouded. 1.94" valves in a 305 is even pushing it.

If these heads are stock, they won't take much more than .450" of lift. I've read 1million times on here that .460" is the MAX.

The stock 305's (if yours is TBI) were spec'd at 58cc chambers, but I've read they actually measure 56cc. If you were only going to use the Vortecs for a 305, then you can get them milled. If you plan to put them on a 350 later down the road, leave them be.

The only concern I'd have with milling them is the deck thickness. I've never seen Vortec heads in person, but if they're like every other GM head, the deck is thin to begin with.

Comp Cams has a spring kit that works well for the Vortecs, although I don't have the part # here next to me. You can call Jegs (800) 345-4545 or Summit (800) 230-3030 and I'm sure they'll know exactly how to help you.

You'll still have to machine the valve guides and perhaps the spring pockets to get more then .450" of lift and to use bigger springs. Either Jegs or Summit will be able to sell you the tools to do that if you feel up to doing it.

 

Don't bother porting them or going to the 2.02's.

You'll likely reduce the overall flow balance on the intake side.

You could port and polish the exhaust to good effect thou.
You'll have to have the heads milled a bit to maintain the compression ratio on the 305.
305 heads are 58cc's and L-31 vortecs are 64cc's.

Note the L-30 305 vortecs are 58cc's and have the 305 sized valves.

 

hrmm...im glad i asked about compression because i have been hearing the opposite

the casting # for my vortecs are: 14101083 (before posting I researched this to be as follows...an excerpt from a site:
-----------------------------------------------------------------
10125377 Cylinder Head Assembly
This is a cast iron cylinder head assembly used on 285 hp 350 engine (P/N 12353641). This complete cylinder head assembly includes 1.94" intake valves, 1.50" exhaust valves, valve springs (P/N 3901068) and valve spring caps (P/N 14003978).
Technical Notes: This cylinder head has 64cc chambers. The cast number for this head is P/N 14101083 or 14096217. This cylinder head has 1987 and later inlet manifold bolt pattern. The center two bolts are at a 72º angle.
------------------------------------------------------------------------

Obviously not vortecs, but what kind of power am i looking at with these as opposed to ACTUAL vortecs.


So far I have it as follows:

Port/polish the exhaust, but not the intake. Leave them @ 1.94, and don't dare take them to 2.02 on my 305 (which is where i plan to keep em). I am beginning to wonder if it's really worth it at all. What is milling exactly?

im a little peeved that these arent vortec heads, shoulda done my homework beforehand i reckon.

 

Not Vortecs.

These are 350 TPI heads. Should have got the 305 TPI heads.

casting #081. 58cc

Give theses the full port treatment. Take them to a machine shop to have them milled to 58cc's. Milling is machining the flat surface to reduce chamber size or just to true up the surface.

These heads will work well once they are fully ported.

You could also sell them off and get some real vortecs.
Vortecs have a unique 8 bolt angled bolt pattern and raised
intake ports.

The 350 L-31 heads are castings 062 an 906
the smaller valve 305 58cc L-30 vortecs are 520 and 059
The 305 vortecs will work well with larger 1.94 intakes
and some minor bowl porting.

 

FBIRD, thanks for all the input on my threads.

What roughly is the bang for my buck in regards to the heads you mentioned


Considering I already have a pair of 350 TPI heads to be milled to 58cc, and fully ported (to what diameter?).

Best to go with 305 Vortecs and have them milled to 58cc?

What you say is the word of ***! where would you put your money, and what would you invest in which heads for a L03 engine?

Heads?
Port diam? int/exh
Milling? 58cc i presume
polish work?

and after your recommendation, what would it cost?

 

any suggestions?

 

Bang for the buck all depends on if you're willing to put the effort into porting your heads or just giving them the once over.
The potential is there thou.

You're best to get and estimate from a shop in your area that can do the work. What I tell ya doesn't mean much if they are the ones doing the job.

The vortecs are a sure bet.

 

If you put 350 heads on a 305 you actually have to open up the top of the bore and use a 350 head gasket. Otherwise the combustion chamber will be shrouded. This same exact question came up on pages 130 and 131 of the new (April 2003) Chevy High performance mag. The answers in there pretty much answer every variable and are from a reputable source. Check it out! It sounds like you're spending considerable cash on that 305. Have you ever considered that same money could be put toward a crate motor or even a rebuilt 350. That would gain you more than the 305 ever will. No substitute for cubic inches

 

Thanks for the input, FBIRd/Street

I'll check out that article. I really just want to have a mild engine in my car without many mods or heavy work (like engine swapping/wiring harness and that jazz). I am just looking for about 375-400 hp all engine with the 305 TBI...but I'd settle for 325-350.

Thanks again
blain