: Should I replace a perfectly good set of 76cc heads?
Mar 4th, 05, 12:19 AM
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
Mar 4th, 05, 04:18 AM
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.
Mar 4th, 05, 06:14 AM
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.
Mar 4th, 05, 06:59 AM
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.
Mar 4th, 05, 07:47 AM
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?
Mar 4th, 05, 08:27 AM
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
Mar 4th, 05, 09:27 AM
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.
Mar 4th, 05, 02:08 PM
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.
Mar 4th, 05, 03:13 PM
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!!
Mar 4th, 05, 04:28 PM
$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.
Mar 4th, 05, 06:18 PM
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.
Mar 4th, 05, 06:31 PM
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.
Mar 4th, 05, 07:35 PM
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?
Mar 5th, 05, 04:34 AM
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?
Mar 6th, 05, 07:05 PM
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!
Mar 7th, 05, 04:48 AM
Originally posted by DenRS:
So you guys believe that just swamping heads could increase hp almost 40hp? Absolutely. Cylinder heads have come a long way in the last 10-20 years. Everyone talks about flow numbers but I'm telling you there is power from modern fast burn combustion chambers too. That's why you could take an old set of double hump heads, port them to the same flow as a set of Vortecs and wind up with less power.
Another pet peeve of mine is that everyone keeps talking about flow numbers and port volume, but noone ever talks about port cross-section. People wonder why a 215 cc GM fast burn head is OK for a 350 when a 210 cc AFR would be too big . . . the answer lies in the port cross-section and velocity through the port.
Mar 7th, 05, 07:08 AM
I with 67 Plum on the light weight Vortec casting and cracking thing; one of the reasons I went with Canfield aluminum heads on my 400sbc. I want dependabilty as well as high performance.
Eric68, speaking of pet peeves, one of mine is no one talks about the Vortec cracking problem and how it made the Power Pack 194 heads scarce. That's the reason my 76cc heads for the 327sbc are starting to look good to me. The 11:1 dome piston solution seems viable, I know this is "old school", but these pistons help make better than 1hp per cubic inch in the 302/327 motors; a good indicator of VE.
Mar 7th, 05, 07:37 AM
Yes, the Vortec heads have been known to crack. Have you ever heard about how the 882's are just as prone (if not more) to cracking? Do some research, they like to crack between the valves.
I think people are taking this the wrong way. Are Vortec heads the best head out there? NO. Are they a some what cheap alternative? YES. Will they make more power than old GM castings ? YES.
If you are starting form scratch and need rockers, valve covers, intake, etc.. then the Vortecs are not a bad option.
It all depends on your budget and your goals.
If you are starting with a core set of older casting heads (ie... camel humps), and have to have them rebuilt (guides, valves, valve job, hardened seats, springs, retainers, locks, etc..) by the time they are ready to run you are going to to have close to as much if not more into them as a set of Vortecs. Even after all that you won't make as much power.
As far as the dome pistons, sure they will work. If you go that route you will probably be better off with old heads as well. The chamber design on most of the newer heads are not designed for dome pistons and the domes actually hurt performance.
If your budget allows by all means go out and get a set of aftermarket heads. One cure is not good for everyone.
Eric, good point about flow and port size. I get tired of hearing how much heads flow. While that is important, that is not all there is to it.
Mar 7th, 05, 08:56 AM
Thanks Royce . . .
gmranch. What exactly causes Vortec heads to crack?
Mar 7th, 05, 11:19 AM
(I think people are taking this the wrong way. Are Vortec heads the best head out there? NO. Are they a some what cheap alternative? YES. Will they make more power than old GM castings ? YES.
If you are starting form scratch and need rockers, valve covers, intake, etc.. then the Vortecs are not a bad option.)
I agree with you Royce , I gues my problem is every time someone says what head to run everyone says Vortec.If starting from scratch this is a good low end street head.If you are replacing a set of standard heads and already have a good intake valve train and covers there are better heads for the price.I was pointing out that used heads can be cracked.The 882s are more prone to cracking than the Vortecs.
[ 03-07-2005, 01:36 PM: Message edited by: 67 Plum ]
Mar 7th, 05, 11:25 AM
Ecir68 they are prone to cracking between the valve seats just like any lightweight smallblock head.The used heads out there can be almost 10 years old.Some of them are from 3/4 and 1 ton trucks a couple of hundred thousand miles and run hot they can have cracks and worn out guides.Just something to think about before buying a used set.
Mar 7th, 05, 11:34 AM
A ? all the tests I have seen were Vortecs vs 882s or 441s with 1.94 and 1.5 valves.What about a set of 186s or 041s with 2.02 and 1.6 valves and some port clean up?
Mar 7th, 05, 01:33 PM
Imho, they should be about the same as the -461, -462 and -291 heads in air flow unless you run into a -461X.
I mention the -461X b/c they are like 170+ cc's vs 160+ or so cc's for regular -461's..
Mar 7th, 05, 02:28 PM
Chad, I understand your point, they are not a $200 upgrade, the cost is often more than expected. In most cases people are just starting to hot rod the engine when they talk about buying heads. This usually means a new intake, roller rockers, pretty valve covers, etc.. So the Vortecs are a viable option over rebuildin old tech castings.
I would not suggest them to someone that already had a great manifold, roller rockers, etc.. on their engine and just upgrading the heads. In that case you are right on you would be better off just buying an aftermarket head. For the price of Vortecs I don't think I would even consider buying used, they are fairly cheap brand new, if you go and buy used ones you are in te same boat as the older castings by the time you get them rebuilt.
Mar 7th, 05, 03:29 PM
I'm not trying to put out the fire with gasoline here; I'm sorry if I upset anyone. I just wanted to point out, in the fullness ot time(I'm an old guy), that when Vortec heads first came out, they had a cracking problem. Many independent repair shops(non dealer;hey,I talk to the mechs. in the trenches) relaced Vortec heads with earlier heads. Thus the supply of ealier heads evaporated, causing myself and others a great deal of consternation.
Mar 8th, 05, 05:11 AM
You didn't cause me any grief, so there's no need to apologize. I was just trying to point out that over-heating is what causes heads to crack whether it be an 882, Vortec, or otherwise.
Granted there were probably some down-right defective heads that cracked under normal use, but I think Vortecs therse days are pretty reliable unless you really overheat them. Someone please correct me if I am wrong here . . .
Mar 8th, 05, 02:08 PM
I got a great deal from these people, I talked to Jim the owner,and he had an "overstock issue". If I had to guess it would be inventory taxes. Still (22320000A = steel,72cc chambers,200cc runners,screw in studs,springs good to .600lift(?),guide plates, assembled and ready to bolt on) Protoplines at a deal I couldn't pass or beat/match anywhere else. Under $700 ;)
Mar 8th, 05, 02:59 PM
I've got over 300 bucks in my 993's, I should have come here first.
Mar 8th, 05, 04:20 PM
Gmranch no problem here if we were talking in person instead of a computer these conversations would work better.I have a hard time expressing my thoughts on subjects when typing with 2 fingers.