truckman5000

Hey, wondering. My friend has a gto, saying it would be a huge difference upgrading heads.
Im not seeing this, as the intake/ ext. valves are the same. My f- heads are ported ext.
Opinions? Thanks

Fun71

Probably depends a lot on the amount/quality of the porting job. I'm not sure anyone can give you a realistic answer without having data on the flow rates between the two heads.

truckman5000

I dont have flow rates.
Dose a fully done f- head = a stock edelbrock? Same valve size, i know the internals could be different but enough to spend 1800$?

shiftbyear

I think if you get honest flow numbers on your heads and match the correct cam for your application you'll be very happy. Don't be disappointed in the flow numbers, Olds heads don't flow very well, even ported. Good luck.

ronskal

You can get cylinder head flow data from the web, Google "Stan Weiss Cylinder Head Flow". It may help you out.

67 Cutlass Freak

I disagree. I recently had my ported "C" casting, cast iron heads flowed. They had mid level porting done by me over 20 years ago. I got 279 CFM @ .700" lift on the intake, and 200 CFM exhaust @ .700" lift. According to this website - http://www.users.interport.net/s/r/s...lehdc.htm#Olds
Dick Miller tested Edelbrock 60519 out of the box intake 253 CFM @ .700" lift & exhaust 192 CFM @ .700" lift. The valve size itself is not the pinch point restricting flow in these heads.
Truckman5000 are you sure those are "F" casting heads? Do you have any photos of the casting numbers in the center of the head by the exhaust port? The only reason I ask is the "F" casting heads are pretty rare, and usually fetch about $2500, or more, for good bare, unported castings. Those heads are usually pretty hard to find, and reserved for guys that are building a numbers matching car.
I recently did some more work on my heads and am hoping to get 300 CFM out of them. They should be going to the flow bench Thursday.

cutlassefi

Dave,
Maybe you can enlighten me as to why you and others even bother to give flow numbers at lifts of .700? Based on what a vast majority will be building, those are a waste of time and imo nothing more than hype. What's it matter if you're not pushing the valve open nearly that far?
As you know Milan, me and others have built 600+hp projects with nothing close to that in lift(mine had .630). So for comparison purposes, don't you think maybe for the Olds community, flow numbers in the .550-.625 range would be more useful and realistic? Unless someone is using a sizable solid roller most won't even come close to that amount of lift.

Jmo, thanks.

truckman5000

So it seems that a worked stock head will flow "the same" as an edelbrock?

My car is a w-30, the F heads are #matching. They were ported 20 years ago or so by someone else.
I dont plan on the edelbrock, trying to keep it original

67 Cutlass Freak

Well Mark, I understand what you are getting at, and you are correct. Probably 98% of the guys on this sight, or running strictly on the street, would never have a cam that large. So why even look at those flow numbers? The reason I posted the .700” specs was because that was the highest lift they posted for the Edelbrock heads. The other reason is because my lift numbers will be higher than .600” and my flow chart is in .100” increments. I also have flow numbers up to .800” but that would be silly. The thing I found interesting is that my numbers kept going up. If someone is crazy enough toutilize fully ported cast iron heads, in an effort to compete with aluminum castings, then they might want to put as big a cam in that will work with their compression ratio. In all fairness, I feel that the numbers under the curve are probably more important than peak numbers. So let’s take a look at them-

Edelbrock: .100” 65/53 .200” 136/103 .300” 197/139 .400”242/167 .500” 243/182 .600” 250.189 .700” 253/192

Freak’s ported “C” castings: .100” 70/51 .200” 135/100 .300”185/142 .400” 223/169 .500” 251/183 .600” 265/193 .700” 273/198



Look at the .300” and .400” comparison. The Edelbrocks are significantly better. This leads me to believe with a smaller cam of say .500”lift the E-brocks would most likely perform better. I am still learning.Cylinder head flow numbers are only one piece of the puzzle. Air speed/ cross sectional area/ and port shape are even more important.

Recently I ported even further on my heads. I hope I didn’t mess them up by going too far. As soon as I get flow numbers I will post up results in the “Home PortingTechniques“ thread.

Truckman 5000, the only real way to find out if your heads flow as well as the E-brocks would be to do back to back flow testing. If it runs good now I wouldn’t mess with it. If you want to get more performance out of your combination, you will have to give us a lot more information. You may even want to talk to Mark, (CutlassEFI), about setting you up with a custom tailored cam for your specific application.

Sorry about the novel guys, just trying to explain why I posted what I did.

Carry on, Dave – The Freak

rad

I'm currently porting a set of B heads just for something to do so any flow numbers or comparisons are appreciated by me for sure, the plan is, is to run my ported B heads and eventually buy a set of bare procomps and port them for a comparison, im following freaks guidlines in the head porting area as a reference since im used to porting chevy heads.

cutlassefi

My filled Procomps flow better at .600-.650 than they do at .700. But all else being equal I'll bet they'll make more power with a cam around .625 lift than yours do at lifts of .700 or better.
Madmax's 480 I just did had modest flow numbers (286@.600) for ported Edelbrocks but made the upper limits of the pipemax estimate. I would venture to say it's because of the quality of flow as well as decent midlift numbers.

Hope this helps.

80 Rocket

The madmax motor is very impressive with the BMEP number. You definitely got the most out of that and the heads were a key factor, as well as the camshaft that was used.

.25D is an equation all should learn. That is to say 25% of your valve diameter (2.07 x .25= .517) is when the actual port shape takes over and does not care about your valve seat, short side radius, and bowl shape (to an extent). On a 2.07 valve, .517 lift is when that all takes place.

Mid lift numbers can make or break an engine when you are reaching for the stars, because how many guys are going with .650+ lift cams with their Oldsmobiles?

The mid lift numbers can be improved with careful attention to the valve seat, valve shape, short side radius, and bowl work.

80 Rocket

Edelbrocks will probably pick it up slightly, but that all depends on the quality of the porting on your F heads as mentioned prior. A set of Edelbrocks with attention to detail and a short block to match will do even more.......and you will probably feel it with the "seat of the pants" feel.

It depends on what you are after....

wr1970

I would agree with this Don. To the op. A lot depends on what your goal is. I see no reason to change out your F heads for anything else.There are plenty of guys with Iron heads on street cars running mid to high elevens.

truckman5000

Sounds good, ill keep them, thanks some great info