Black Baja

iTrader: (2)

If you call the top cylinder head guy in the country. That has all the Prostock wins over the last 5 years and does all of the cup heads and tell him you want to go race Prostock he will tell you it's $150,000 and you get three sets of heads and 2 intakes. That's all you get. No flow numbers.

When I spoke to Bob about using a set of heads from Curtis Boggs (no flow numbers) he said it was no problem. Soon after that conversation I called Bullet talked to Tim (I always check up on people I deal with). Explained the situation of no flow numbers. Again response was its no problems.

I've ordered cams from other companies and decided on using different heads for the build. Camshaft never changed.

Panther

It's just my opinion but you want to know flow numbers in selecting the right cam. Advertised numbers don't always tell the story either because a lot of those numbers are listed at max lift, like 700 or more. Back that down to 650 or so and now we're looking at numbers that might make more sense. Some heads don't flow well with a certain amount of valve lift and if you don't match the lobe profile to what the heads like then you're leaving power on the table. It's not a be-all-end-all but it's definitely important when choosing the right cam to go along with your heads. If you don't know exactly you can still guestimate and pick a decent cam but I don't think I would rely on that. Again, just my opinion.

Panther

I spin them up to 6K rpm.

With the Merlin heads the boat ran about 87mph. Several years later I bolted the 357's on and didn't change anything, literally bolted them on and I picked up 300-400 rpm and the boat ran 92.3 mph with the solid cams. Then several years later I with the new engines and the hydrualic cam I picked up another 1-200 rpm and the boat runs 95.4mph GPS.

[ATTACH=CONFIG]550245[/ATTACH]

CPM

Back in the day when Chet was still alive he made us some bh2 cams on a 114* they were a straight profile 240 @050 and 640 1.7 they made great numbers on 540ci and under engines with a nice idle, I still have a few of them left I think we did a run of 100 back then sold most in packages I really liked them.

MILD THUNDER

iTrader: (3)

So basically, you are saying that a 502 with gm iron heads, will be ideal with the same cam, as a set of cnc ported afr heads ? Why? Because their intake port volume is the same ?Or maybe even a big chief head ? So a 502 with a 325cc head, irregardless of brand, will utilize the same cam? What data is the cam designer using to design the cam if he has no idea what the heads flow?

ICDEDPPL

iTrader: (1)

i`d say those top guys are protecting their numbers that`s why they don`t give em out, kinda like cam guys won`t give you all the specs either.
Designing a cam without head flow numbers is equivalent to a mail order tune.

On a side note, why does Bullet cams have the cam recommendation page? What a waste of time filling out all that info and receive no response.
Jones got back to me within 24hr. I don`t agree one bit with the cam choice but at least he got back to me

KWright

Hmmm so does that mean after you get the head you can't flow them.

MILD THUNDER

iTrader: (3)

EngineLabs: How important is it for an engine builder to own or have access to a flowbench, and why?

Curtis Boggs: Personally, when I’m involved in an engine build I want to have the most data possible. For an engine builder it really depends on the level he/she wants to work on in the cylinder head program. There’s a ton of good data for an engine builder with a flowbench. Once there’s a fair amount of data collected over several builds, it becomes easier to identify trends. A good cylinder head supplier would take some the pressure off of the typical engine builder to log flow numbers. However if the builder uses several different sources for heads it could help with data and identify trends if they did it themselves. It’s important to flow heads from different sources on the same bench with the same technique. Typically when one of my customers, or any engine builder, buys a flowbench, they learn some things very quickly. First, it doesn’t take the huge flow numbers people think to make power or win on Sunday, and a peak flow number isn’t the most important number. There’s a tremendous amount of data for an engine builder. I wouldn’t build anything without one.

EL: Anything else you can say about flowbenches or airflow in general, beyond what has already been published in Engine Labs?

Boggs: Well, only that I have a reputation for saying that flow numbers don’t matter, and that couldn’t be farther from my intention. Flow numbers are very important—we are working on air pumps basically. However, the other things in a cylinder head like I mentioned earlier are as, if not more, important also. The biggest flow number doesn’t always win.

EngineLabs: How important is it for an engine builder to own or have access to a flowbench, and why?

Curtis Boggs: Personally, when I’m involved in an engine build I want to have the most data possible. For an engine builder it really depends on the level he/she wants to work on in the cylinder head program. There’s a ton of good data for an engine builder with a flowbench. Once there’s a fair amount of data collected over several builds, it becomes easier to identify trends. A good cylinder head supplier would take some the pressure off of the typical engine builder to log flow numbers. However if the builder uses several different sources for heads it could help with data and identify trends if they did it themselves. It’s important to flow heads from different sources on the same bench with the same technique. Typically when one of my customers, or any engine builder, buys a flowbench, they learn some things very quickly. First, it doesn’t take the huge flow numbers people think to make power or win on Sunday, and a peak flow number isn’t the most important number. There’s a tremendous amount of data for an engine builder. I wouldn’t build anything without one.

MILD THUNDER

iTrader: (3)

Good info from Curtis Boggs about flow benches and airflow

http://www.dragzine.com/tech-stories...w-flowbenches/

Panther

I'm surprised to hear that. My experience has been difference. Hopefully that's just a one-off experience you had.

Below is from a SBC I built a few years ago.[ATTACH=CONFIG]550248[/ATTACH]