f-85

We need to see some numbers from stock BB heads. Its not a good comparison SB heads vs procomp/edelbrock (bb heads) Also need some flow numbers from mild ported BB heads. If you guys look at the numbers from the sheet. 7a stock vs 7a with a bowl blend. It picked up almost 30cfm at .600. Now if you do that to a BB head (lets just say they flow 220 at .600) stock vs one with a bowl blend. If it gets the same gains as the 7a did then you will have a Bb head that flows more then the procomp and about the same as the edelbrock. Now if you can get that rebuilt and done for less then $1000 it seems to me the best choice for a street motor.

kitfoxdave

The last column are BB "B" heads with 12-15 hours of work in them....
Hopefully we will get some before and after BB numbers.


When we do, I will gladly add them to the spreadsheet guys...

J-(Chicago)

Now that's using your old noggin'

These threads won't be a friggin song and dance on here like R.O.P. I'm hoping.

Kitfoxdave, your chart is a GOOD idea.....BUT due to the differences in flow benches, Only before and after gains on the SAME flow bench are even worth posting.
I posted my stock number, and the cfm gain before and after on a single bench. the +35cfm is the only valid data.
Everyone else is comparing nonsensical CRAP. Mark called a guy in idaho with a DIFFERENT flow bench. Numbers were awesome, but without the baseline start, they're pretty useless. Smitty's bench might have showed 300cfm for those heads, where the guy in idaho could be at at 250. Brian trick posted his awesome set of heads as well, but that was a different flow bench as well.
I'm trying not to get frustrated here, but big block heads compared to small block heads is stupid, and ported irons or stock compared to aluminums on 3 different benches is also stupid.

Smitty's bench could say 310 and my machinists bench could say 250. Who is right? only the timeslips will tell, and even then, they're inside of 2 totally different cars, or on 2 different dynos.

67 Cutlass Freak

Calm down young one, have a beer. I agree 100% that comparing flow numbers from different benches does not make sense. It's OK to compare SB to BB heads, but everyone knows going in the BB head is going to stomp the SB. I still want to see a basic ported BB cast iron against the ProComps on the same flow bench. I keep hearing about how out of the box they flow better than ported cast irons. I want to see it for myself.

coppercutlass

The only numbers that matter are track numbers imo. Everyone brags hp and flow numbers yet very few people post track times. I know for certain pourposes head flow and hp numbers help but for a street strip build what pourpose I don't see it as benificial honestly.

cutlassefi

FYI most of the heads on that spread sheet were done on the same bench, by the same guy. I'm trying to get stock BB heads done as well but maybe that would just be "stupid". Chill out.

J-(Chicago)

Red bull gives me wings I guess. I realize tone of voice is difficult to convey via text. I wasn't hollering, just emphasizing.

I just don't want some poor guy viewing a comparison of a stock sbo head and a ported edelbrock bbo head, and thinking he's going to go do wheelies with no compression.

Whether we like it or not, the things we post influence people for the better or the worst.

Hell, that one guy a couple posts ago is all revved& ready to pull his iron heads and chuck em into a pond lol.

I applaud all posts that we can learn from, I just don't want people compiling all kinds of randomness into lists that have no meaning. I'm here to help.....

I don't even think kitfoxdave even added all of the new random info to his list, so I'm not jumping on him either, just making it a point to only compile worthwhile data no matter who the member viewing these threads.

J-(Chicago)

I have all kinds of iron heads here that we can pull data from, and in various port and valve sizes as well.

I have some full race mondello irons, a pair of mike glasby's old irons that he was running 9.40's with, a set or 2 that I ported, and of course.....a huge pile of j's lol.

kitfoxdave

I am just providing a free service (that eats deeply into my extremely limited free time) trying to put together info that people feel is in the ball park (leaving off the info people know is out of range).


Remember that not everyone is using the BBO engine. (Isn't that right 380racer)


I have been listing the testing location and pressure when I have that info so that people can at least compare stuff from the same test facility.
Altitude, temperature and attitude of tester have a lot of impact on the flow data.
I hope over time we will have enough data collected from heads before and after work being done to see what is worth the money to do and where it might be better spent. That is why I am also trying to collect cost numbers as well...
I already have my engine, and expect to be very happy with it. The dyno numbers show it is what the engine builder and I discussed. I have a different "mission profile" than the racing folks, so naturally my goals were different. Where the rubber meets the road is the important part ultimately and how the entire car is built will determine that. I appreciate all the comments and opinions, but most of all I appreciate the data.


My intention is that when I have more info I will have a spreadsheet for the BBO heads comparison, and SBO heads comparison. Again I am just trying to help out folks...


Dave

Smitty275

Just to touch on something mentioned a few posts ago about engines of supposedly same power and going into cars of similar weight, yet performing nowhere near the same on track. It happens but its because other is HP to be found in the chassis set up. Lots of HP. Well, its not really making more HP, but it is making better (or worse) use of it. So often times that is the difference. Its not always fudged dyno numbers.
Just sayin'.

HWYSTR455

How small can you get the chambers on ProComps and Eheads without it impacting flow? Wouldn't going too far start shrouding the valves?

.

Smitty275

I think 55cc to 50cc would be as small as I would want to go. With a traditional Olds chamber decking the head doesn't change flow much at all and it is for the better. On a modified chamber like the new E'brock the more you deck it the better if flows. The gains are small but they are there.

HWYSTR455

Excellent, note taken, thank you!

.

J-(Chicago)

How do you feel about the structural integrity of the head once you mill more than .060 from it? At what point would you start o ringing things Smitty?

Smitty275

I wouldn't take more than .100 off the deck of any factory iron Olds head. With the coming of Cometic gaskets O-ringing is pretty much a thing of the past on N/A engines. Running 15 to 20+psi of boost I would still O'ring and use copper head gaskets. If your going over 12:1 I would also recommend upgrading to 1/2" head studs.