vortec heads

[mike's 86 c10]

I need some info i just got a set of l-31 heads. I am going to take them to the machine shop for some work and have a valve job done on them. I have read a lot of differant post on votec heads and every body has differant opinions i need hard facts.

I have a 77 block bored .30 over it has never been decked i just put a new crank in it and a comp cam part num is 12-210-2.

the specs are
Intake Duration at 050 inch Lift 218
Exhaust Duration at 050 inch Lift 218
Advertised Intake Duration 268
Advertised Exhaust Duration 268
Valve Lift with Factory Rocker Arm Ratio 0.454 int./0.454 exh.

Ok i need to know what needs to be done to these heads?
Im not sure if i wont to get differant rocker arms like a 1.6 for more lift or stay with what came with what came with the heads?
Some post say that the use of push rod guides are a must but i have found some rocker arms that say self alining like the stock one?
I need some info so i can ord a intake right know my operating range is from
1500-5500 if i put some 1.6 on will this change that?
If i can get some feed back it would help i wont to ord my intake and stall sone.

thanks

[Zoomad75]

Here's what you need your machine shop to do to the Vortec's while they have them. First, have them enlarge the spring pockets for standard size small block springs. L31 springs are a smaller than normal diameter and will be a limiting factor to a larger than stock cam.

Second, have them machine down the valve guide bosses. The L31 valve guide bosses are the problem with higher lift cams as they are tall enough at max lift the spring retainer into contact with the guide. That's not a good thing at 5,000 rpm.

Those are the main two items to get done. Yes you don't have to do them if you are running a small cam, but it's easier to do now and know you can move to a larger cam later without having to pull the heads again.

[81ShrtBox]

Originally Posted by Zoomad75

Here's what you need your machine shop to do to the Vortec's while they have them. First, have them enlarge the spring pockets for standard size small block springs. L31 springs are a smaller than normal diameter and will be a limiting factor to a larger than stock cam.

Second, have them machine down the valve guide bosses. The L31 valve guide bosses are the problem with higher lift cams as they are tall enough at max lift the spring retainer into contact with the guide. That's not a good thing at 5,000 rpm.

Those are the main two items to get done. Yes you don't have to do them if you are running a small cam, but it's easier to do now and know you can move to a larger cam later without having to pull the heads again.

You do not need to get anything machined for larger springs. Get GM Z06 Beehive springs and Competition cam retainers. Simple swap out. Can handle way more lift than what you are gonna throw at'em.

Here's the link: http://67-72chevytrucks.com/vboard/s...d.php?t=437325

[wardee1977]

I bought the tool from competition products to cut down the valve guide with an electric drill. Gave me plenty of room for a high lift cam. I also ran comp cams behive springs that were matched for my cam that dropped right in. They are a little pricey, but so is a trip to the machine shop.

[ont_guy_38]

You cannot use push rod guides and self aligning rockers together , it has to be one or the other. I use just the self algining rockers

[wardee1977]

I used a set of aluminum full roller self aligning rockers. No need to drill and tap for screw in studs and guide plates.

[gmclowsierra]

i have the vortec heads on two engines i built. i put comps extreme energy in both .477 .480 lift and i havent done anything to them. i put the springs in that comp said to go with and they both work great. mine is .030 over with flat tops. mine has never been decked and neither has the heads. it put the compression somewhere between 10.0:1 to 10.5:1

[mike's 86 c10]

thanks for all the reply's i called the machine shop today and they said that the guide's are ok like they are but new spring will need to be put in. I will see what spring's will work good with my cam. How about intakes any recommendation's i need one from 1500-5500?

[oldblue1968chevy]

edelbrock performer/edelbrock performer rpm

what cam are you going to run (curious), or what cam are other vortec users using.