BBC-Aluminum heads?

[Bandit]

Hey all,

I am trying to justify the 2 grand + it would cost me to have a set of new aluminum Edelbrock or equivalent heads on my 402 Chevy Big Block. I am trying to guesstimate what kind of power and torque increases I would gain.

Sorry I don't have all the specs with me right now, but I'm currently running the following:

Block bored .010 over for 408 ci
Domed Wiseco 9:6:1 pistons
Stock oval port heads 2.19" Int 2.25" exh
stock stamped rockers
Comp hydraulic roller cam <.600 int/exh
Crane hyd. roller lifters
Edelbrock Performer intake
Holley 750 vaccuum secondaries
Hooker 1 5/8" primaries...2 1/2" dual exh w/H-pipe

Etc...basically your typical mild street build with the huffing advantage of the roller cam.
Never been on a dyno, but we estimate 400-430 flywheel hp/450 lb. torque.
I would like to squeeze out closer to 500 hp from her, how close can I get with just the heads?
Also, I want to keep the stock exhaust port locations for ease of header fitment. So no radical Brodix monsters for me.
I will likely combine the heads with an Edelbrock Performer RPM intake.

So:
1. How much power/torque can I expect to gain?
2. How much weight will I drop off the nose of the car?
3. Can I drop compression ratio a point or 2 (to support future procharger install) and still see a decent gain?
4. If you have any suggestions for runner size/chamber or head shape, I'm all ears!
5. This is a "tall-deck" block from a truck originally, will this mess me up?

Of course I know any estimates will be ballpark, there are like 30 different heads from Edelbrock alone that will fit my engine. :doh:

Sorry for the long post, but I value your inputs. :help:

Paul

[EFI69Cam]

Hey all,

I am trying to justify the 2 grand + it would cost me to have a set of new aluminum Edelbrock or equivalent heads on my 402 Chevy Big Block. I am trying to guesstimate what kind of power and torque increases I would gain.

Sorry I don't have all the specs with me right now, but I'm currently running the following:

Block bored .010 over for 408 ci
Domed Wiseco 9:6:1 pistons
Stock oval port heads 2.19" Int 2.25" exh
stock stamped rockers
Comp hydraulic roller cam <.600 int/exh
Crane hyd. roller lifters
Edelbrock Performer intake
Holley 750 vaccuum secondaries
Hooker 1 5/8" primaries...2 1/2" dual exh w/H-pipe

Etc...basically your typical mild street build with the huffing advantage of the roller cam.
Never been on a dyno, but we estimate 400-430 flywheel hp/450 lb. torque.
I would like to squeeze out closer to 500 hp from her, how close can I get with just the heads?
Also, I want to keep the stock exhaust port locations for ease of header fitment. So no radical Brodix monsters for me.
I will likely combine the heads with an Edelbrock Performer RPM intake.

So:
1. How much power/torque can I expect to gain?
2. How much weight will I drop off the nose of the car?
3. Can I drop compression ratio a point or 2 (to support future procharger install) and still see a decent gain?
4. If you have any suggestions for runner size/chamber or head shape, I'm all ears!
5. This is a "tall-deck" block from a truck originally, will this mess me up?

Of course I know any estimates will be ballpark, there are like 30 different heads from Edelbrock alone that will fit my engine. :doh:

Sorry for the long post, but I value your inputs. :help:

Paul

The tall deck is going to mess up your header location anyways.

For a 402 the ovals are hard to beat, but if you have have aluminum heads the edelbrock "Rovals" are one of the best flowing heads on the market short of AFRs and some of the huge runner heads like brodix.

Personally, I'd spend money getting a short deck block first, no sense carting all the weight and going through the bother of a tall deck block for only 402 cubes.

[Bandit]

For a 402 the ovals are hard to beat, but if you have have aluminum heads the edelbrock "Rovals" are one of the best flowing heads on the market short of AFRs and some of the huge runner heads like brodix.


What's a "Roval?" I have never heard this term before.

Guess I should have explained my situation better: I have been running this engine for about 3 years now. No problems, exhaust fits and the motor seems to work well with my suspension setup--but I could use a little more juice. Want to keep it streetable though and not ready to mess with nitrous yet.

I would prefer a new World or Shafiroff 540 :naughty: , but it just ain't happening any time soon. Anyhow my 402 is going strong, would just like to upgrade a bit and shed some lbs. What problems would I have with aftermarket heads on a tall block--I thought they were the same dimensions, or if not, I could just use thicker gaskets?

Paul

[rocketman]

I you have headers now there's nothing change but the heads.

I don't the Edelbrocks heads,I would go with a AFR's,that small of a motor you don't want a crazy big head anyway.You might just port the heads you to,there good power alot cheaper than new heads.

If you are thinking a big cube motor like a 540,just go 632.

[EFI69Cam]

The edelbrock 454-O heads are the ones with the rectangular oval port. I would not put even the 305 CC AFRs on a 402. A 402 does not have the displacement to build any velocity through a port that size.
I have the GM version of the edelbrock ovals on my 540 and although I am considering AFRs, I will try my current heads first.

[rocketman]

if you could find some aluminun 396 hds those would be perfect for it

[442olds]

Good luck finding some factory aluminum 396 heads for less than $2000. For the money the eldelbrock/gm perf part head is the best there is and it uses the factory exhaust port location to boot. I have a set I'm working on putting in my vette now. I can't wait.

But what I really have to ask is, being a tall deck, how long are your conecting rods. if your still using stock length 6.135's, you must have one heavy piston to push around. And what's bore and stroke are you running.

[MarkM66]

On a small cubic inch bbc. I don't think cylinder heads would be worth the investment, as your stock oval ports can keep up pretty will with your cubic inch. I'd put your money in building a bigger engine.

[xx_ED_xx]

You can easily build a 540 out of that tall deck. If i understood you correctly that you are running a 402 tall deck now..

[neki67]

What's a "Roval?" I have never heard this term before.

Roval is in between Rectangular and Oval.

[rocketman]

Are using a tall block,sound like you have a ten over 396 block.

You could pick 50-75 horsepower and lose 100 pds.

[xx_ED_xx]

402 is a .030 over 396 :squint:

[TD509EFI]

5. This is a "tall deck" block from a truck originally, will this mess me up?

I'm getting confused here... GM only made 366 or 427 tall deck engines, which one is this?

John

[xx_ED_xx]

What i was wondering as well...
:git:

[rocketman]

402 is a .030 over 396 :squint:

I knew that.math was a little wrong

[rocketman]

5. This is a "tall deck" block from a truck originally, will this mess me up?

I'm getting confused here... GM only made 366 or 427 tall deck engines, which one is this?

John


Thats my question you can't get a 366 to 408 with a strokin it

[Bandit]

5. This is a "tall deck" block from a truck originally, will this mess me up?

I'm getting confused here... GM only made 366 or 427 tall deck engines, which one is this?

John

You are correct. Just seeing if you knew that... o not really, some yahoo told me awhile back that it was a tall deck, but I have since realized that it is NOT a "tall deck" motor. So that's what I get for listening to my punk friends. :screwy:

So now that we got that out of the way, my original question remains: which heads? Again, they must be a stock-replacement bolt on, I do not have the ability to fabricate headers etc. in my current location (in Italy). I am mainly looking to pick up an honest 50hp, maybe lower my compression a point or 2 (the gas here sucks), and drop 100 lb. off the nose of the car.
I am thinking I will go with Edelbrock "rovals like some of you suggested, but they have may choices of runner sizes etc. That is where I would like advise on what to invest in. Also, can I lower the CR a bit and still see good power increase? I would like to end up with a 9.4-9.5 ratio if it will not cancel out my gains. Right now it's at least 9:6:1, maybe more since I have had the heads shaved once.

That is why I am consulting with all you engine gurus out there.
Thanks--

Paul

[malihoochie]

The Edelbrock heads have a "odd" chamber shape. Be aware of this, 'cuz many people find out too late. It is a cross between a closed & a open chamber. I'd go with a smaller set of Darts or Brodix heads with a conventional open chamber.

Hope that helps.

[kman67rsss]

I am running a 402 BBC .060 over with 11:1 cr and have AFR magnum 305 heads. rund good and has 385 HP at the rear wheels. thats close to 500 at the crank. so it can be done

[xx_ED_xx]

Hell i am confused? so bandit you have a 402? with what heads currently?

[TD509EFI]

For a stock replacement , it's tough to beat Brodix Race Rite Oval port heads. A direct bolt on with no mods due to exhaust port location.
Brodix makes a quality product, and though I haven't used the Race Rites, I've heard good comments from others.

John

[Bandit]

Hell i am confused? so bandit you have a 402? with what heads currently?

Yes, it's a BB 402, bored .10 over, with the stock oval port heads. I can get the casting # if it helps. But I know they are the low-flow small oval port castings, the shop that built the motor said the engine could gain a lot from some better heads.

[xx_ED_xx]

Ah Ok. I think you have what are refered to as peanut port heads. And yes they suck great for towing motors that are kept below 4000 rpm about it. IF it was me i would put a set of large oval ports on it. 2.19 1.88 valves. but i know u are tryin to take weight off the nose as well. but hell i couldnt justify spending 2 g's on some heads just for that reason.

[Bandit]

Ah Ok. I think you have what are refered to as peanut port heads. And yes they suck great for towing motors that are kept below 4000 rpm about it. IF it was me i would put a set of large oval ports on it. 2.19 1.88 valves. but i know u are tryin to take weight off the nose as well. but hell i couldnt justify spending 2 g's on some heads just for that reason.

I can justify it--if I would have got these heads from the beginning I could have saved myself the trouble of a cracked head, the cost of rebuilding on the heads, and the frustration involved. And saved some weight off the nose.

[rocketman]

Brodix race rite heads,can't go wrong

[EFI69Cam]

I can justify it--if I would have got these heads from the beginning I could have saved myself the trouble of a cracked head, the cost of rebuilding on the heads, and the frustration involved. And saved some weight off the nose.

The edelbrocks sound like the way to go. Don't be afraid of the smaller chamber, its an excellent design, and will increase your compression a point or two. Check piston to valve clearance though.

[fotoboy]

Headers too small IMHO, I had 1 5/8 and went to 1 7/8 on a closed chamber 396 pump gas motor, was a huge difference.

[pdq67]

I didn't think anybody made 1.625" BB headers so what gives??

366" tall decker to a 408"???

You guys notice all the BS info given out in this thread??

Guy, please do your homework AND feed us the right info so we can help you!!

pdq67

[Bandit]

I didn't think anybody made 1.625" BB headers so what gives??

366" tall decker to a 408"???

You guys notice all the BS info given out in this thread??

Guy, please do your homework AND feed us the right info so we can help you!!

pdq67

Forget the header size, it's beside the point! It's a 402 BB, bored .10 over for about 408 ci. It's NOT a tall deck motor, somebody told me wrong! It has stock oval port heads, I just want to know which aftermarket heads I should buy to improve it!!

[fotoboy]

I didn't think anybody made 1.625" BB headers so what gives??

366" tall decker to a 408"???

You guys notice all the BS info given out in this thread??

Guy, please do your homework AND feed us the right info so we can help you!!

pdq67

I had 1 5/8 header on my 69 396, not that hard to figure out what size they were, they were way too small, pretty sure I know what I am talking about.Sorry you dont think its possible ir 2 people on this post had them.

[fotoboy]

I had 1 5/8 header on my 69 396, not that hard to figure out what size they were, they were way too small, pretty sure I know what I am talking about.Sorry you dont think its possible ir 2 people on this post had them.

I used to spin my 396 with closed chamber oval ports past 7 k on a reg basis, smaller cc runners would benifit better on a 396

[Sundance]

http://www.strokerengine.com/page/page/1268049.htm

[xx_ED_xx]

:1st:
Great link

[rocketman]

Just use Brodix Race rite heads and set of hooker super comp headers.

[fotoboy]

cool write up

[Bandit]

For a stock replacement , it's tough to beat Brodix Race Rite Oval port heads. A direct bolt on with no mods due to exhaust port location.
Brodix makes a quality product, and though I haven't used the Race Rites, I've heard good comments from others.
John
Thanks to you and Mr. rocketman for turning me on to these fine heads. I did in fact go with Brodix, ordered up a set of 115 cc chamber Race-rites. According to the Summit racing tech, using my 402's casting #'s, my stock heads are a 113 cc chamber. So I should drop a point or 2 of CR, which is OK with me because good gas is hard to get. I should still pick up some good HP with these heads, right? Of course I will check piston-to-valve clearance and pushrod length before installation. Is there anything else I should check?

PS Sorry about putting out any bogus info earlier, and any confusion that may have resulted--I wrote my initial post without having my engine specs in front of me--a mistake I won't make again! :doh:
I do appreciate all the help!

Paul

[xx_ED_xx]

what cam you running and pistons?

[Bandit]

Cam specs:
Comp hyd. roller
gross valve lift .566/.566
duration at .006 tappet lift 280/280
duration at .050 int 224/exh 224
lobe lift .3330 int/exh
lobe separation 110.0

Pistons:
Wiseco Part # PT039H6
Piston # 5039H6
Compression height: 1.760
Bore: 4.1550
sugg clearance: .0050


I was just doing some research online and I discovered conflicting info about the heads currently on my motor, casting # 336781. All the info I have found says they are open chamber 454 large-port oval heads. But some sources say 113cc combustion chambers and some say 118cc. What gives? Can somebody tell me which it is for sure? Will the 115 cc chamber Brodix heads I ordered make a significant difference in my compression ratio? Also, are these Brodix heads going to be worth the price of admission?

[xx_ED_xx]

Well with heads it varies depending on how many valve jobs etc best thing to do is cc the heads then you know for sure. Piston have any dome? And what did you have to do to run a hyd roller? i have been considering this on my 454

[xx_ED_xx]

supposedly 10.5-1 with your current setup and new heads, the cam will help bleed off cylinder pressure

[xx_ED_xx]

If you would of got the 119 heads it would be 10-1

[Bandit]

These pistons have a dome +38cc according to Wiseco's website. Which yields 11:1:1 CR with 110 cc chambers according to them. Which makes my CR with Brodix RR heads with 115cc chambers ????

A local engine shop put my engine together years ago, so unfortunately I don't really know what they had to do to install the roller cam. From what I understand there's not much difference other than it costs about 5X more, and break-in is much less finicky.

[Bandit]

If you would of got the 119 heads it would be 10-1
Umm...that's not good news! :eek:
I was looking for around 9:5:1 CR, or at least some CR that I can live with on the street. I think 10:5 is way too high for 92 octane, am I right? Should I call Summit and tell them to get me the 119 cc heads instead?

[xx_ED_xx]

Not sure how long ago you ordered them but i would

[Bandit]

Not sure how long ago you ordered them but i would
OK I'm confused though. Right now my CR is fine with my factory heads for 92 octane. I don't know exactly what it is but below 10:1 for sure. My chamber size is supposed to be 113 cc. So with 115 cc heads my CR should be lower. :hmm:
Where are you getting these numbers from if I may ask?

[JChristian1835]

I always thought a smaller chamber raised compression and a bigger cc lowered it...

[xx_ED_xx]

http://car.race-cars.net/calculators/compression_calculator.html

If you dont know the cc of your heads then the arguement is m00t.

The too big cam helps a bunch with bleeding off cylinder pressure.

Get hard facts to make a comparison its alot easier that way. i am just taking the info you feed me tryin to help you out.

[Bandit]

http://car.race-cars.net/calculators/compression_calculator.html

If you dont know the cc of your heads then the arguement is m00t.

The too big cam helps a bunch with bleeding off cylinder pressure.

Get hard facts to make a comparison its alot easier that way. i am just taking the info you feed me tryin to help you out.
Please, I am not trying to argue with you, just trying to figure out
A: What is the combustion chamber cc for BB chevy heads casting # 336781.
B: What will my final CR be with Wiseco piston 5039H6 (+38cc dome) using Brodix Race rite 115cc chamber heads.
If this info is totally unobtainable without CC'ing the heads then that is what I will do, but it will take time that I really don't have because I have to get the old heads off and have them CC'd. It would be nice if I could figure out what I am going to end up with in advance.

[xx_ED_xx]

:twothumbs
Its cool...
But you have to understand you need all the info to make a correct choice
I just went thru this recently i thought the closed chamber heads on my 454 were 100 cc ended up being 110 cc so the compression i thought i had i didnt. so when i got my pistons i knew what my compression was going to be since i want to put a blower on it. and i want around 9-1 comp to do that.
Also the cam was humongous especially for 8.5-1 compression
so it was a dog til about 4000 rpm then it wasnt too bad. needless to say find out what you have. You are chagning the heads right? If your old heads happen to be 119 cc and you get this other set of heads your kinda doing opposite of what you were tryin to accomplish right. With that being said i have run 11-1 on the street with pump gas as well. Hell alot of the new cars do too so...

[Bandit]

Thanks for all the tech help, I see now that I will definitely need to get my current heads cc'd to find out where I'll be at with these new ones. (I guess that's what you've been trying to tell me all along)

After researching these GM heads on other sites, most sources say they are 113 cc chambers but some guys have reported up to 120 cc. And my heads have been shaved a time or 2 so who knows what they are at this point. Now I wish my pistons didn't have the +38 dome.
But I am not planning on boost anytime in the near future, so maybe a 10-11:1 CR might be ok after all.

Thanks again to all who helped me science this out!