Should I replace a perfectly good set of 76cc heads? - Team Camaro Tech
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post #1 of 29 (permalink) Old Mar 3rd, 05, 11:19 PM Thread Starter
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I have a set of 333882 chevy heads on my Camaro. Looks like they are 76cc chamber,194/1.5 valves.

With performance street cruzing in mind, would it make sense to replace these heads. I'm wondering how much of a difference I would feel and if it is worth it.

I would like to use iron heads.


A desktop Dyno run would be great. Cam @.050 is 218/224

Thank you

68 Coupe, 327, TH-350, 3.08, Holley 4bbl Carb,Edelbrock RPM Heads, Edelbrock EPS intake, Comp Cam XE262H-10, Jet Hot Headers, Vintage Air
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post #2 of 29 (permalink) Old Mar 4th, 05, 03:18 AM
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The 882 head is your typical smog-era 70s head. It flows about 210 cfm on the intake side max...

An aftermarket head such as the AFR 180cc, Pro Topline 180cc, GM Vortec, Dart Iron Eagle (etc, etc) head will move much more air. The aftermarket head will also usually have a smaller, more efficient, combustion chamber increasing compression while still resisting detonation better than your old head. Plus, if you go with an aluminum aftermarket head, you've also dropped 40 pounds off the front end of the car.

As far as horsepower is concerned... I'd guess that most of the heads I mentioned above would be good for 40+ horsepower over the 882s.

Here's a desktop dyno for you... take it for what it is worth.

Using your XE262H-10 cam, guessing at 9.5:1 compression, dual plane intake, headers, open exhaust, 327 cubic inches, etc...

With the 882 heads, 9.5:1 compression... 340 horses @ 5500rpm and 389 # torque @ 3500rpm.

With the GM Vortec head (still at 9.5:1, although your compression would be a bit higher due to the smaller chamber)... 362 horses @ 5500rpm and 397 # torque @ 3500rpm.

With Edelbrock's Performer RPM head (still at 9.5:1 but see above)... 369 horses @ 5500rpm and 399 # torque @ 3500rpm.

With Pro-Topline 180cc head (compression at 9.5:1 but see above)... 382 horses @ 5500-6000rpm and 405 # torque @ 3500-4000rpm.

With AFR 180cc head (compression... yadda yadda)... 381 horsepower @ 5500-6000rpm and 404 # torque from 3500-4000rpm.

Whatddya know! The Pro-Topline beat AFR in this particular desktop dyno. Kind of a surprise actually...

So, going from your 882s to a set of Pro-Toplines shows an increase of about 40 horses and 15 # torque at peak.

John

- '68 Chevy Camaro (sort of done, but always subject to improvement)
- '63 Pontiac Tempest (work in progress)
- '72 Datsun 240-Z (back-burner for now)
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post #3 of 29 (permalink) Old Mar 4th, 05, 05:14 AM
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what about the rest of your combo? If you got flat top pistons now, your compression is less than 8:1 now. Going to a 70 or 64 cc head to bring the comp up to 9.5-10:1 will have a huge effect on torque throughout the rpm range.

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post #4 of 29 (permalink) Old Mar 4th, 05, 05:59 AM
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It all depends on what you want to do with the car. The question was kind of vague. If the car is used to commute and that's it, then there is no need to spend the coin on new heads. If you want to make more power then there is no better way to do it.

I had a set of fully ported 882's spent a lot of money and time on them, they performed OK, I finally broke down and bought a set of Dart Pro 1's and I can tell you the difference is amazing. You will feel the difference.

It basically comes down to what it's worth to you, there is no doubt the performance will imorove (even if you went with a set of Vortec heads). Heads are the key to power. So if spending $800 - $1,200 (depedning on heads, gaskets, etc..) is in your budget and you want to make more power, then go for a set of heads.

Only you know what you want.

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post #5 of 29 (permalink) Old Mar 4th, 05, 06:47 AM
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Food for thought, I've also got a pair of perfectly good 76cc heads(from a 400cid sbc) laying around and a 215hp 327 that needs a rebuild. What about using domed pistons in a rebuild, to raise the CR and these using these 76cc heads?
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post #6 of 29 (permalink) Old Mar 4th, 05, 07:27 AM
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on a 327 w/76cc, you'd need a heck of a dome to get the comp over 9:1. Such a piston would shrould the valves badly, reduce flow and VE, and probably be prone to pinging. you'd be way better off with a 64cc head and a flat top or 1/8" dome piston

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post #7 of 29 (permalink) Old Mar 4th, 05, 08:27 AM
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I agree with Jim, a dome piston is not the best way to raise compression. It used to be the way to go but, for many of the reasons Jim mentioned it is not the "best" choice these days. Flat tops or even dish pistons have better performance "potential".

With the price of heads these days and how far technology has come, I wouldn't really waste time on old GM castings unless it is for a restoration or a race class that the rules specify that's what you must use.

You can pick up a set of Vortec heads for a couple hundred bucks and they out perform the old castings hands down.

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post #8 of 29 (permalink) Old Mar 4th, 05, 01:08 PM
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Vortecs!!! They are about perfect for a street 327 and will make better power than your 882 heads. They have a much better combustion chamber design and have 64cc chambers which will bump your compression up a full point. If you are up to it a little clean up work in the bowls will help even more.

Desktop dyno says your compression ratio with flat top pistons and a .040 quench height with the 882's is 8.3:1. Horsepower is 321 @ 5500 RPM and TQ is 346 @ 4000 RPM.

Switch to Vortecs and your compression jumps to 9.5:1. Power goes to 348 HP @ 5500 and TQ goes to 366 @ 4000 RPM.

I think the incrtease is on the conservative side because DD2k does not take into account the extra power you would see because of the improved combustion chamber design.

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post #9 of 29 (permalink) Old Mar 4th, 05, 02:13 PM
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FWIW, just installing a stock set of medium valve double hump heads on a 210hp/327 motor and you will have a stock 275hp/327 motor!!

Add a set of 3.36 to 3.55 rearend gears and I will guarantee your combination will put a smile on your face that Mr. Clean can't wipe off!!

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post #10 of 29 (permalink) Old Mar 4th, 05, 03:28 PM
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$800.00 to $1200.00 to pick up 40hp. Or 100 to 150hp. $369.95 NOS Snipper system from Summit.The advantage with the 882s and 8.3to1 comp. is it will run on the cheap crap gas.They also have hardened valve seats that the old hump heads dont.
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post #11 of 29 (permalink) Old Mar 4th, 05, 05:18 PM
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The extra HP from the heads is there always. There is no bottle to refill, not switches or solenoids to fail. Now I am not knocking Nitrous and if he wanted to add that on top of the new heads that would be great.

His question was simple but, left out a little detail. He asked if a head swap would be a good idea. He didn't ask how to get the most HP per $.

He could have a set of Vortecs for much less than $800 too.

Just depends on his goals, which still aren't clear.

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post #12 of 29 (permalink) Old Mar 4th, 05, 05:31 PM
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With new heads , intake and rockers you will spend $800.00 to go Vortecs.You have to be carefull with used Vortecs they are lightweight castings and do crack.Not that I am against Vortecs but he has a good intake already so some of the heads John listed would require less changes.
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post #13 of 29 (permalink) Old Mar 4th, 05, 06:35 PM
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More food for thought- my goal is just to have the original 327 motor, for a spare cruiser, slightly improved with some parts I have laying around the shop and some parts that I have to purchase......I'm on a budget here. OK, I have 882 heads, a Holley Contender dual plane intake, a 215hp 327 that needs a rebuild. So let's say I bore it and put in 11:1 OEM dome pistons(that would be about 9.25:1 CR with the 76cc heads), add 2nd design Z28 hyd. cam; what kind of HP & Torque numbers could I expect at 5500rpm?
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post #14 of 29 (permalink) Old Mar 5th, 05, 03:34 AM
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I'm in the same situation as Sgrouse. I don't plan on racing, but I want more hp in my camaro. I have the same heads on my 350. My engine was rebuilt and doesn't have more than a few thousands miles on it. It was in the car when I bought it, so I don't know anything else about it. I do know everything on it is edlebrock 1406 carb, performer manifold, so I believe I have an performer cam in it. I'm not 100% on the cam, but its not stock. I figure I'm around 290-300 hp now, and I was going to throw on a set of Trickflow 195. So you guys believe that just swamping heads could increase hp almost 40hp?

1969 Camaro 350, Trickflow heads, ST-10 4spd, Hotchkis suspension, Baer SS brake kit, moser 12bolt
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post #15 of 29 (permalink) Old Mar 6th, 05, 06:05 PM
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When I first rebuilt my Camaro I put a set of stock reconditioned 1.94 heads in it. They didn't last long (long story) so I put a set of Trick Flow 23 degree heads in as replacements. The difference is amazing, I wish I would've done it in the beginning. Beside the power increase, my mileage went from about 9 mpg to 15!

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