My head casting numbers are 458642 according to one website (Mortec)these are 75 and up 350 heads. according to another site they are 68 327 heads and according to 3 sites they are 67-70 350 or 400 heads. can someone clear this up. What I really need to know is the cc's of the head, I am looking at geting some vortecsa but want to make sure my compression wont go too high.

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72 RS Split Bumper 327 700R-4, Cowl hood
Dark blue pearl w/white stripes "See picture"

I have an interchange manual, and it also lists the heads as 67-70 350/400 heads.

I don't know how much this helps, but now you have 4 sources that say that. http://www.nastyz28.com/ubb/wink.gif

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350CID, Vortec 062 heads, Magnum 268, Performer Intake, Holley 650 DP, 3.42 rear w/ Auburn posi, 2000 Stall/TC

Look for the casting dates to determine what year they are made.

The number 458642 is wrong? I find 468642!

If its the later, they are common heads used on a lot of 350 and 400 small blocks. I do not find any 327 engines listed in my books. All the applications I find are 1971 to 1985, they appear to be smog heads as they were used in a lot of light duty applications although they saw a stint in 1980-85 Corvettes, they primary use was trucks.

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Mike

2002 Trans AM WS6 build #3124 - Pewter
2001 GMC Ext Cab SLT Z71 - Green