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Author Topic: SBC Hump Heads  (Read 1548 times)
pjbizjak
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« on: November 03, 2012, 08:55:27 AM »

Hi All; I'm about to take a 1200 mile trip to check out a pair of 3917291 68 Z/28 2:02 heads that are date matched to my 68 04a built z/28. I don't have a lot of time, so I can't take them to a machine shop to have them professionaly checked out, so I need some advice as to what to look for as far as potential problems.

Thanks
Pete
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68camaroz28
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« Reply #1 on: November 03, 2012, 09:16:03 AM »

Pete, no expert here but of course threads and parts that would indicate they had not been used and abused like stock studs (even though they would be upgraded to the look orig but screw ins) and 'O' rockers. I always check the exhaust seats and combustion chambers and if you had a machinist metal straight edge to check flatness.
Now, what you might consider is how best to feel like you making a fair or wise investment by some other electroic means and not having to travel 1200 miles for a set of heads.  Even arranging some type of inspection at your cost would be much cheaper in the long run. Just some thoughts out loud but good luck. Our Z wishes your Z luck as well  Grin
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Chick
68 Z/28 NOR 01B Orig motor/trans/rear
69 Z/28 NOR 07A Orig Block & GM Cross-ram/carbs
69 L34 Rest. Nova Father/Son Car
69 L78 Surv Nova Purch 4/69 31K miles
67 L89 Corv Tribute
68 Corv 427/400 Orig motor
07 Corv Z06
R 68Z build- http://www.camaros.net/forums/showthread.php?t=182584
JohnZ
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« Reply #2 on: November 03, 2012, 10:51:53 AM »

The 291 casting was machined for two different sizes of valves - standard was 1.94"/1.50", and the Z/28 was machined for 2.02"/1.60" valves. The 2.02" version had the valves almost touching, and the side of the chamber wall adjacent to the intake valve was machined for an unshrouding cut to improve airflow. 1.94" heads field-converted to 2.02" valves frequently didn't have the unshrouding cut done, and they flow less air than the 1.94" heads. Photo below shows a factory 2.02"/1.60" 291 chamber with the unshrouding cut - that's what you want to see.
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'69 Z/28
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« Reply #3 on: November 03, 2012, 11:20:18 AM »

You might ask the seller to take the heads out and get them checked for cracks before you make the trip. Offer to pay for the check as you would do this any way and you might save the cost of the road trip.
Mike
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dannystarr
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« Reply #4 on: November 03, 2012, 04:43:56 PM »

Here is that picture I always like to use. It gives ya a little info about what JohnZ was talking about. Check the arrows for the spacing between cylinders. That material he is talking about causes smaller gaps between. BUT, keep in mind, thaqt CAN be cut out. But it has a different look to it when it is done AFTER MARKET. Also a picture of my heads I sold. I would have the guy take 10 pictures and email them to ya FIRST. Then post them here for the experts to examine. You make that giant drive to find out they are a "dime a dozen" 194 heads, you won't be happy. Just any guy with 2 cents to throw in.. Good luck eh.  .. Danny
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rodent
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« Reply #5 on: November 03, 2012, 05:30:54 PM »

Pete, I'm not 100% sure about the external differences between the the 2.02 and the 1.94 heads, but why not get a set of the 1.94'(cheaper)and get them cut and unshrouded and you would end up with a virtually new set of heads(valve seat wise)?

Below are some pics of 291's, one set are 302 heads the others are standard fuelies. The 302 heads are dated 28 0f March '68 and the others are 18 October '67(neither are for sale sorry)

These heads are currently out,  so if you need more pics of them let me know.

cheers
Jim

PS, Chick if you read this,  I still can't get near my car to get pics of the speedo cable Sad I have to move a heap of cars and it's a pain in the butt Sad I'll take them when I do get near it though.










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68camaroz28
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« Reply #6 on: November 03, 2012, 05:56:31 PM »

PS, Chick if you read this,  I still can't get near my car to get pics of the speedo cable  I have to move a heap of cars and it's a pain in the butt  I'll take them when I do get near it though.

OK, got it Jim!
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Chick
68 Z/28 NOR 01B Orig motor/trans/rear
69 Z/28 NOR 07A Orig Block & GM Cross-ram/carbs
69 L34 Rest. Nova Father/Son Car
69 L78 Surv Nova Purch 4/69 31K miles
67 L89 Corv Tribute
68 Corv 427/400 Orig motor
07 Corv Z06
R 68Z build- http://www.camaros.net/forums/showthread.php?t=182584
mopar346
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« Reply #7 on: November 03, 2012, 07:26:17 PM »

At the cost of fuel, even down right now, seems you could have the checked and shipped MUCH cheaper. Of course you don't get the fun of the road trip and seeing other stuff the guy may have in the corner. I had a set shipped from NJ to Fl for $57 last year.
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1968 Z28
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« Reply #8 on: November 03, 2012, 08:19:18 PM »

  My take on this....I bought a set of date correct 291 heads on eBay for $100.00 and $100.00 shipping. The heads were 1.94 heads taken off a motor and sold to me as is.  I took them to my machinist to have them modified to the 2.02 valves....well guess what....on one of the heads, two of the rocker arm bosses were cracked.  They were then unusable for restoration heads, although I did go ahead and have them fixed to sell later.
  Later on, I found a set of the same date correct heads in Pennsylvania, but they were cleaned, magnafluxed, and guaranteed rebuild-able for $550.00 shipped.  These turned out to be exactly what I needed and in excellent shape.  The second time around it wound up costing me more but at least I got what I needed.
  So, I would recommend that you should do the same.  Also, I would recommend to start with a pair of the 1.94 heads and have them modified to the 2.02 specs, thus winding up with an almost new set.

  My two cents.....
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Jerry G.

Z28-1968-07C-Norwood
Ermine White, Red Std. Interior
2nd. Owner, 38,000 miles
pjbizjak
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« Reply #9 on: November 04, 2012, 05:09:11 PM »

Thanks to all for your help....I must admit that the 1200 mi trip was to Florida for vacation and then a side trip to see the heads, so the trip was two fold. I currently have a set of 291's, both are original 2.02's but one is original that came with my 04A build Z with correct date and the other is a replacement with a date that doesn't match the build date. The heads in question are both date correct, mid to late March 68. Engine assembly date 0329.

Pete
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mopar346
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« Reply #10 on: November 04, 2012, 06:46:47 PM »

Where in Florida? If it is near me I can have a shop I trust test them and then package and ship them for you. I'm in the Tallahassee area, but am Flying to Philly for 2 weeks in the am.
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pjbizjak
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« Reply #11 on: November 04, 2012, 08:42:12 PM »

Lakeland, by Tampa. Thanks for the offer.
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