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5.7 Vortec Heads

11K views 4 replies 3 participants last post by  xntrik 
#1 ·
I've read where The 062 Vortec heads flow much better (particularly from the exhaust port) than the other "Vortec" castings. other casting #s are 906


well the 117,000mi 5.7 SBC Vortec engine I found has the # 10239906 head. he said he would let it go for $450 to me, we been good friends since grade school. hes in the office of a salvage yard and said hes sold prob 40 pair of vortec heads, and has yet to see a 062 casting head. the circle trackers are buying the 10239906 Vortec Heads up. I'm looking at a $450 for a running SBC plus the cost of a LT1 cam swap, and new valve springs (the LT1 cam cause I want to) intake, Carb & HEI and electric fuel pump to get the 63 moving. you think the 906 heads are that bad of a choice ? I will do all the machine work to the vortec heads when 5.7 vortec is tired and I build my next SBC, prob including bigger valves. the vortec motor is temporary (1 1/2 to 2yrs is max I would run the vortec motor) till I can afford to build my 383


Mustangsaly
 
#2 ·
I believe what you read was in an older magazine. I have worked with both casting no's and they look and act virtually the same. The 906 heads are more common because they came on pickups. SOME have hardened exhaust seat inserts. These would be the less flow castings. But still not that much less. And a more reliable head.

If you purchase the motor. Get a gaurantee IN WRITING that the heads will be replaced if cracked! Most all of the Vortec 5.7 heads I get in from vehicles that have worked for many miles are cracked across the center exh seats and toward the center head bolt hole. These are GM lightweight castings. Also get the guide and spring work done..
 
#3 ·
Bob,

I was going to replace the Valve springs, back to stock (just so there new for the new cam) and put new gaskets in it, and a LT4 cam in it with an intake, holley carb, and Mallory HEI (as I have a new mallory HEI & a recurve spring kit) and Holley Electric Fuel Pump & run it.

LT4 Cam is slightly milder than the ZZ4 Cam. LT4 Cam = (203*intake duration vs 208*), would be the LT4 cam, part no. 1255142, which has only .450" lift (with 1.5 rockers), I Thought I might get by with out any head work at all with this LT4 cam,


Either way from what I've read, I will need an old-style HEI distributor with mechanical and vacuum advance, and will need to use the GM "melonized" distributor gear (part no. 10456413, ~$25) for it to be compatible with the roller cam.

you think I should Also get the guide and spring work done B4 running it basically in stock form, except for LT4 cam ?

I just want to run the vortec motor 1 or 2yrs at most, till I can recover from the investment of the Nova build, and build my 383 the way I want. I have a complete early 70s std. bore 4 bolt main 350. in my stash I have a good GM Steel Crank, so I could build a 355 with the rebuilt machined vortec heads

then when this vortec is tired, I will do all the machine work on the heads and reuse em on my 383 build or build a 355 build.

this $450 or $500 117,000mile vortec motor sounds like a good start to get the nova moving, plus it's 4 my son as he will probly learn a lot from building it with me, and from tearing it up showing off :nono: when he starts driving it everything will be done, except the 383 I want, and I'm Not sure about the tranny at that point (tranny might not be the one built for the 383. the 1st 350th tranny will be a good starter tranny, depends on my funds at that point), the narrowed 31 spline ford 9" with the ladder bar rear frame setup will be under it, and the 350th with a 2800 stall converter. when we get a yr outa the vortec, I want to add some laughing gas 75 to 125 shot for fun. plus this will give him some 1/4 mi. strip time with a loose SBC on laughing gas

all suggestions / advice and help welcome. I Know Nothing about nitrous, whats best wet or dry ?




Mustangsaly
 
#4 · (Edited)
the vortec/valve lift discussion and avoid going into detail about the fact that a guy can use a ZZ4 cam without any special machine work having been done on the heads. This place makes a kit (part#R5400SLRK) that lets you run a .600 lift cam, but I'm not sure I'd be brave enough to take my vortec heads that far. .510 Is what a friend is using now works just great.





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