gruveb

After reading some reports about Vortec heads and the vortec cast iron heads scoring near the top in every catagory I decided to take a second look at them.

My concerns are with the lift and the rocker arms.

First off all, can I use my current roller tip rocker arms off of my stock L69 heads?

Secondly, the cam I have is Competition Cams XE-262H-10
Part Number 12-238-2
Intake Exhaust
Lift .462 .469
Duration 262 intake 270 Exhaust.

Can I use this cam with the heads without any modifications other than changing the springs?


Last but not least, I figure that I will lose a half a point in compression switching from a 58cc combustion chamber to a 64cc combustion chamber. Is that correct?

fast_broker

iTrader: (1)

Perfect cam for those heads. if the roller-tippeds are 1.5 ratio, you are good to go. Spring change is all that is required. But, may need to convert to screwed-ein studs if the stonger springs and faster ramps puul them out but you should be ok with that cam.

Not sure of the CR change but I think the compression would be lowered by about what you stated or near .55 lower.

You really want about 9.0+ CR with that cam and those heads, though, and 9.5 is ideal. Make sure you have at least 9.0 CR!

I'll assume you run a carb and are not EFI. Have fun! You'll need a Vortec intake, too, BTW? I suggest Performer RPM Vortec or RPM Air Gap Vortec.

gruveb

Fast_Broker,

Yeah, carbed. If I go this route it'll be an Edelbrock RPM Air-Gap intake, speed demon 650 carb and Hooker super competition headers with either a 3 1/2 inch single of a set of dual 2 1/2 inch exhausts. I already have a Jacob's Pro/Street ignition.

Should be a wicked combo. Hopefully I'll be around 350 horsepower with the combo.

Then if I like it and decide to keep it I'll add a little juice!

five7kid

iTrader: (14)

We're talking a 305, right?

Not a good choice. As said, springs, screw-in studs. Then shave to get your CR back up to respectable territory.

Save yourself the hassles and get World 305 S/R Torquers. Have the springs, have the studs, have the chamber size, benefit from bowl work. But, they're made for the 305, use a less expensive intake, etc., etc., etc. If you're willing to do the die grinder work, you'll spend less money and have better flowing heads than the Vortecs.

Don't listen to the Vortec Pied Piper. Get the Worlds. Desktop Dyno puts me at 362 HP @ 6000 RPMs.

five7kid

iTrader: (14)

Don't forget you also need self-aligning rockers with Vortecs.

Mark305TBI

and centerbolt valve covers.

F-BIRD'88

Here's what you'll need to do to run your vortec heads.
Replace the valve springs with stock diameter hi perf springs.
Measure the distance between the stock vortec retainer and the top of the valve seal(requires dissassembly). You must have min .060" more room here then what ever valve lift you will be using. Most heads will need to have the top of the guide shortened. Do not listen to others who have done this or run that,
measure yours!!! *.100"+ clearance is recommended* If you want to use non-self guided rockers, you will need to install guideplates. This will require screw in studs.
If you want the same compression ratio as with your stock heads,
you will have to mill down the vortec heads to match and use the same thickness head gasket as stock. Or mill the heads even more to accomodate a thicker replacement gasket. This is critical on a 305 so get it right.
When done right these heads will outpower and have more
torque and throttle response than S/R torquers even after porting. There is more to these heads than just the raw flow
numbers. Good Luck

DM91RS

Just installed them on my LO3. It runs much stronger. I changed the springs. Installed Crane .050 offset keepers and added one shim under the spring. I am running a .480 lift cam. The clearance is around .040. Not perfect but enough. More can be gained by running different retainers or by removing .050-.060 from the stock ones (I checked). The stock retainer to seal number was from .465 to .470.

I did not worry about the compression loss. Not much in my opinion to warrent milling .

Good luck!

gruveb

Well, I was seriously considering the World Products heads.....but I re-read the Dec 2001 issue of Chevy High Performance. The Vortec heads rated near the top in everything.

And according to the article, it was for much more than just mere flow numbers. It had a lot to do with the combustion chamber shape.

Besides, either way I have to do some work on the heads, so why not end up with the better product when I'm done? And if I keep the heads without milling them I could apply them to a larger displacement engine later.

But even with all of the extra stuff I need, I can pick it up for about what the World Products heads cost. They cost under $500.00 a set assembled. So that is my thinking.

While 360 hp is about the goal I am shooting for I think I'm gonna go Vortec.....at least that is what I am thinking right now!

five7kid

iTrader: (14)

If a future larger displacement engine is part of the equation, then don't get the Vortecs shaved. But, whatever head you choose, wanting the heads to work on both engines will cause either the 305 or the bigger engine will suffer - you pick which one.

The Vortec combustion chamber design is an improvement over other factory heads, but that doesn't imply the Vortec chambers are better than aftermarket heads. The World 305 chambers are quite different from factory 305 chambers, for instance.

I don't agree with your logic, since your $500 assembled doesn't include the work you're going to have to do just to make them work with your cam (or the reassembly that will have to take place with that work); and doesn't include the other parts you are going to have to get (intake, gaskets, rockers) to make them work, period.

I don't agree with your logic.