Re: 557 build A-heads

c.evans January 30th 2014, 5:20 pm

dirt_worker wrote:
c.evans wrote:
norm wrote:These are Motorsport A heads. Aren't they down a bit flow wise compared to a more modern A head? Trickflow, idt etc.

Yes they are down a bit, but they should be busting 440 cfm pretty easy if they are ported. 442 cfm is where we were in 2001-2002.

Charlie

Charlie, what size sleeve do you flow all your stuff on?

I flow my big block Ford heads on a 4.625" bore, and before you make an issue about the bore size, may I suggest that you read this from the Brzezinski web site about cylinder size.
http://www.castheads.com/removable_cylinders.php

Charlie Evans

BOSS 429 January 31st 2014, 10:07 pm

If you want real numbers, Use the correct size bore.

Nothing more, Nothing less

c.evans January 31st 2014, 10:35 pm

BOSS 429 wrote:If you want real numbers, Use the correct size bore.

Nothing more, Nothing less

Rich,

So am I to assume that you use Brzezinski Racing Products flow testing equipment? What are the sizes of the bore sleeves that you own, and how many sleeves do you own?

Charlie

BOSS 429 January 31st 2014, 11:51 pm

No, they mostly do small block stuff, and say it doesn't make a lot of difference on those, and suggest to people to buy just a few tubes to save money with their flow bench, That's fine, That's the way they see it. I prefer to do it with the correct size. If a D0OR-E head is going on a 4.390 bore it get's flowed on a 4.390 bore, not a 4.500. A BLUE THUNDER head going on a 4.440 or 4.500 bore shouldn't be flowed on a 4.600+ tube size

We have what ever size we need, or we get it.

Gary Blair February 1st 2014, 10:10 am

I prefer to test a given head on the bore it is intended to be used on.

You can go pretty fast on the old Ford stuff @ 425 cfm with a 2.35 valve.

Barney February 1st 2014, 12:46 pm

X3. Whats the point in flowing a head on a bore it will never see, unless your just doing comparison befire after testing.

68galaxie February 1st 2014, 12:51 pm

Regarding bore size and flow testing.

Bore size makes a reasonably large difference on Ford FE stuff. Testing head flow at 4.05" bore vs. 4.25" bore makes a big difference. Probably depends on how shrouded the intake/exh valves are by the smaller bore. If the cylinder walls are not impacting flow on a small bore, then I can certainly see a larger bore having little to no effect.

BBF stuff I have not seen back to back 4.40" vs. 4.625" tests. Maybe someone has?

windsor February 1st 2014, 1:23 pm

Uh oh.....

c.evans February 1st 2014, 6:43 pm

You all can certainly do whatever you want to do, I am not questioning your flow numbers. However, the industry standard with porting and flow testing is to use the Brzezinski Racing products stuff. Even SuperFlow sells it with their flow benches. I choose to believe the people that know more about flow testing than the rest of us combined do, that being Brzezinski. Furthermore in my own testing, using appropriate different size bores, I see very little difference. The flow numbers remain relative to each other, meaning a gain in numbers is a gain, and vice versa. We have bore sleeves ranging in size from 3.700" to 4.625", and I know I give "real" flow numbers also.

If we follow Rich's theory one step further, then when a guy does a feshen up over the winter and changes bore size for example, from 4.390" to 4.440", then he should have his heads re-flow tested. Reason being, that his flow numbers are all going to change a bunch. I don't believe so.

Charlie

68galaxie February 1st 2014, 10:00 pm

Going from 4.390" to 4.440" probably changes very little on an A head deal. However, would going from 4.440" to a 4.625" will change a bunch on an A head?

If the quoted flow numbers of 427 cfm @ 0.800" was on a small bore of 4.440" it is probably decent. Would that head on a 4.625" bore fixture flow 440 cfm? I would assume at least a 15 cfm difference?

c.evans February 1st 2014, 10:15 pm

68galaxie wrote:Going from 4.390" to 4.440" probably changes very little on an A head deal. However, would going from 4.440" to a 4.625" will change a bunch on an A head?

If the quoted flow numbers of 427 cfm @ 0.800" was on a small bore of 4.440" it is probably decent. Would that head on a 4.625" bore fixture flow 440 cfm? I would assume at least a 15 cfm difference?

No sir, it is not a 15 cfm difference. It has been a few years since I did the back to back testing on different size bores, but it was less than 5 cfm difference.

Charlie Evans

Barney February 1st 2014, 10:27 pm

c.evans wrote:
68galaxie wrote:Going from 4.390" to 4.440" probably changes very little on an A head deal. However, would going from 4.440" to a 4.625" will change a bunch on an A head?

If the quoted flow numbers of 427 cfm @ 0.800" was on a small bore of 4.440" it is probably decent. Would that head on a 4.625" bore fixture flow 440 cfm? I would assume at least a 15 cfm difference?

No sir, it is not a 15 cfm difference. It has been a few years since I did the back to back testing on different size bores, but it was less than 5 cfm difference.

Charlie Evans

I find that difficult to believe, especially on an A head. Next time I get a chance ill chuck mine up in a 4.42 and compare them to my 4.600 numbers and post up the difference. Mine are 2.42 1.94 deals and that may amplify the results a bit given the small bore shrouding.

c.evans February 2nd 2014, 12:19 am

Go right ahead, and remember than the A-460 heads are a canted valve head. So the further the valve opens, the further it moves away from the cylinder wall, therefore making the so called cylinder wall shrouding a moot point.

Charlie

Barney February 2nd 2014, 12:28 am

I understand that. Ive never done testing on an unintended bore so ill be interested to see the results.

bbfstanger February 2nd 2014, 1:21 am

so does a 2.40 valve clear a 4.440 bore?

powerstrokeace February 2nd 2014, 2:18 am

bbfstanger wrote:so does a 2.40 valve clear a 4.440 bore?

I think you need to clearance the block on the intake valve side. I would put the head on with light springs and no pistons and look from the bottom up and push the valve open and close to see. Charlie says as the father the valve opens the more it moves away from the cylinder wall

Ace

bbfstanger February 2nd 2014, 12:40 pm

powerstrokeace wrote:
bbfstanger wrote:so does a 2.40 valve clear a 4.440 bore?

I think you need to clearance the block on the intake valve side. I would put the head on with light springs and no pistons and look from the bottom up and push the valve open and close to see. Charlie says as the father the valve opens the more it moves away from the cylinder wall

Ace

yeah i know how to check for clearance,i dont have my valves yet to do so.
figured someone would know or had tried it before.

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