got ahold of some 462 double hump heads and was wanting to use them on my 350. I heard that they are good heads and was hoping that they will due until i can afford some after market heads. The problem that i see is that they don't have any tapped holes for the alternator or A/C. Can this be done at a machine shop or am i out of luck here. :confused:

 

25 years ago, they'da been worth 'something'.....
Of course, 25 years ago, we couldn't call & get BRAND NEW aluminum heads shipped to our door, either!
Save your $$$, and get a set of GOOD heads when you can afford them. You 'may' get decent machine-work done {personally don't know of anybody who's had this done successfully}; then again, they may be 'junked' in the machining process, and then you'll be outta your $$$ AND have boat-anchors.
Unless you'll be running NHRA/IHRA 'class' racing, where you run a 'specific' head, or are restoring a numbers-matching C3, why use the 462s? Any of the after-market (and GM) heads have better technology (port-configuration), thicker deck-surfaces, etc., and are BRAND-NEW castings.....
Just my $.02 worth.....

 

Glensgages is right, 25-30 years ago they were the real schiznitz! They are just good heads now. Modern designed heads are so much better right out of the box. A set of Vortecs $450, brandnew will out flow and out perform the double hump heads. Of course Vortecs probably aren't as strong a casting as the double-humps, put they sure perform good. Of course they require some machining for anything bigger than a .450-.470 lift cam, and a special manifold, but the guys that have them love 'em.
Check the Chevy High Performance for their comparisons of all the aftermarket and stock heads available on the market. It will be in the Tech Arcticles.

 

Hi Shawn,

I've got 462 camel hump heads (or as we call them here in Finland, "Mickey Mouse heads") installed on my 350 SB, and they've given me decent performance.

I was considering upgrading to Vortec heads, but in my research I came across the site http://www.kendrick-auto.com/head_flow_figures.htm where I found some interesting flow bench numbers comparing stock Vortecs with 462s that had basic pocket porting performed. What surprised me is that the difference isn't as huge as you might think.

GM 462 w/ Pocket Porting, 2.02 Intake/1.60 Exhaust
http://www.kendrick-auto.com/462_chevy_head.htm

Lift / Intake / Exhaust / EIR
0.050 /   45.4 /   25.5 / 56.1%
0.100 /   80.8 /   55.0 / 68.0%
0.200 / 127.1 / 109.1 / 85.5%
0.300 / 169.4 / 136.4 / 80.5%
0.400 / 202.0 / 158.9 / 78.6%
0.450 / 216.9 / 172.8 / 79.7%
0.500 / 222.8 / 179.2 / 80.4%
0.550 / 224.3 / 184.0 / 82.0%
0.600 / 225.8 / 187.2 / 82.9%

These numbers are after pocket porting the head. Pocket porting showed up to 4% gain on the intake side, and a pretty significant up to 30% on the exhaust. Notice also the excellent exhaust/intake ratio (EIR).

GM Vortec as Stock, 1.94 Intake/1.50 Exhaust
http://www.kendrick-auto.com/vortec_cs_gm_head.htm

Lift / Intake / Exhaust / EIR
0.050 /   37.6 /   26.3 / 69.9%
0.100 /   68.1 /   51.8 / 76.1%
0.200 / 136.1 / 105.9 / 77.8%
0.300 / 193.1 / 134.8 / 69.8%
0.400 / 222.8 / 144.4 / 64.8%
0.450 / 228.8 / 146.8 / 64.2%
0.500 / 228.8 / 147.6 / 64.5%
0.550 / 225.8 / 149.2 / 66.1%
0.600 /    NA /    NA /    NA

These are purportedly stock Vortec flow figures, before they pocket ported the Vortec as well. (You can also check out the link for figures after the port job, which showed up to 3% gain on the intake and up to 16% gain on the exhaust.)

You can see that with regards to the intake flow, the ported 462 performs very close to the stock Vortec throughout the range of measured valve lifts, and even better than the Vortec at the first two measurement points. On the exhaust the 462 is actually easily outflowing the Vortec, even up to 25% at 0.550 valve lift. :eek:

Based on these figures I decided not to go for the Vortecs, but rather to pocket port my existing heads this winter and use them while saving up bucks for top-of-the-line AFR (http://www.airflowresearch.com) or Pro Topline (http://www.protopline.com/) aluminum heads.

Naturally, this course of action is only tenable if you're willing to do the port job yourself. Having a professional do it would cost enough $$$ to make the Vortecs a better investment. For myself, I've never done any cylinder head porting but am going to tackle it with the help of guide books by David Vizard etc.

(After all, the worst thing that can happen is that I'll ruin these 35-year-old heads and need to get the AFRs sooner :D)

So I say bolt the double humper heads on if they're at all in usable condition. As for the accessories, you can easily mount them using separate accessory brackets (I can take a pic of my setup if you'd like) :cheers:

Best regards,
Arto

 

thanks Arto a pic would be great. I too am hoping to get head better heads after. Right now i have the body off and have allot of things that are costing me and thought that these will be easy to replace later. With the frame off and the paint removed i have allot to get done by spring. Thank in advance for you help.

:cheers:

 

I'll take some pics for you when I get my Vette back from the paint shop next week (having it painted Magnetic Red :cool:)

But you can do a forum archive search for "alternator bracket" and that should get you started.

E.g. according to the thread at http://forums.corvetteforum.com/zerothread?id=593043 Dynomax makes the bracket you need. It bolts up to the exhaust manifold.

Part no #88301 / GM, Early Style Front Alternator Bracket
http://www.dynomax.com/documents/acc_tools.pdf
http://www.jegs.com/cgi-bin/ncommerc...85&prmenbr=361 $15.99

Hope that helps. There really should be no need to create accessory holes in the heads themselves.

Arto

 

If they are in good condition (read this as can bolt on as is) and you have larger chambered heads now, you would be able to tell the difference. They are very good heads compared to other stock heads of that age, but I agree with everyone else. If they require a trip to the machine shop you may as well save your money for a new set. The accessory holes are easy to drill. I've done it before with a hand drill.

 

Agreed tose heads were the cat's azz a few years ago, I would still use them. Here's what you do, read up on do it yourself porting. There are articles and books etc. that will tell you a few things that can be done at home home without a flow bench that will get you a few more horses and will not f' up the heads. :D