GT 40P flow rates

[48fordnut]

Anyone have any numbers for the flow on GT40P heads?

[bwguardian]

You can look up DIY porting GT40p heads and get some numbers.

[48fordnut]

Thanks BW.I saw that earlier. I have a set of alum heads that I bought off e bay and they are in the shop now for flow test. I wanted to compare to see what gains there were.

[PaceFever79]

Ford Muscle - Head to head flow charts

[Ethyl Cat]

^^^^^ That chart is pretty accurate.

[Ethyl Cat]

Here is a great place to look for that information as well.

http://users.erols.com/srweiss/tablehdc.htm

[Ethyl Cat]

1000 posts!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!

What heads did you get?

[48fordnut]

EC,I really don't know as there is no brand marking on them.

The head porter said they looked like a Pro comp. I have used that brand before with good results on a SBC. He took a couple of valves and seemed to be satisified with the cnc work.
This is for a street car that will never see the strip. Not while I own it. I'm not building the eng for that. In the car now is a 93 5.o that has a B cam and a set of 40p heads. I haven't gotten down on it yet as I'm still building it.

I'm old and sometimes this is a notional thing.

[Ethyl Cat]

If you can, post the valve sizes and ask your machinist to check the intake runner volume when he is done flowing them . It could be good info for folks on here.

[48fordnut]

The valves are 2.02 and 1.60 runner vol will be done when I get the flow sheet.

I thought about another set of p heads, but when you get to checking prices these were the best bet. Even after buying screw in studs and rockers. Plus loosing 53 lbs

[48fordnut]

Ok folks heres the news .porter said he liked the heads. Intake vol is 190cc c/c is 64cc.

at 28''and .700 lift the intake flowed 244.He said he thought he could take them to 275 with porting.At .550,where my cam is the intake was 236.

.700 for the exhaust was 183.9

Will be milling them to 60cc chambers.

I' rn out of money or I would have done the ex vol.

Hope this helps some one.He said these are close to Pro comp heads.

[Ethyl Cat]

Ok folks heres the news .porter said he liked the heads. Intake vol is 190cc c/c is 64cc.

at 28''and .700 lift the intake flowed 244.He said he thought he could take them to 275 with porting.At .550,where my cam is the intake was 236.

.700 for the exhaust was 183.9

Will be milling them to 60cc chambers.

I' rn out of money or I would have done the ex vol.

Hope this helps some one.He said these are close to Pro comp heads.

What cubic inch are they going on?

[48fordnut]

306/with 4 eye brow flat tops.

[PaceFever79]

(ported) seems like a lot of head for a 306 street motor...

Let's see what the expert thinks? ;-)

[PaceFever79]

(myself I'd probably leave the ports stock on a street 306)

[bwguardian]

Ok folks heres the news .porter said he liked the heads. Intake vol is 190cc c/c is 64cc.

at 28''and .700 lift the intake flowed 244.He said he thought he could take them to 275 with porting.At .550,where my cam is the intake was 236.

.700 for the exhaust was 183.9

Will be milling them to 60cc chambers.

I' rn out of money or I would have done the ex vol.

Hope this helps some one.He said these are close to Pro comp heads.

It sounds like these may be GT40 and NOT GT40p heads...

[48fordnut]

I just wanted them flowed. I never said any thing about porting them.

BW these heads are alum .I wanted to know how much better than 40p heads they were.

[PaceFever79]

Yeah they flow way more than GT40p. They won't make as much torque below 3000 rpm, but will rev hard to 6000 rpm with a good valve train.

It could be a little "peaky" but very rev happy.

[Ethyl Cat]

Did you deck the block?
What piston number is it?
Carbed or efi?

[48fordnut]

Did you deck the block?--- Piston is .010 in the hole
What piston number is it? Don't know
Carbed or efi?

.Carbed with a dual plane ,and a 600 carb

[Ethyl Cat]

Heads are a definite improvement but with that big valve and slightly big runner you want to be careful of getting too big with the cam if you want any bottom end.

I come up with about 9.2:1 compression with a .040" gasket and 9.5:1 with a .027" gasket (recommended) as well so with an aluminum head you are going to be down on cylinder pressure. You can build it up with cam and ignition timing though.

Something less than 280 (270-274) seat to seat and no more than 220 @.050".

.550" lift is a tad much with that bigger valve. You could get away with just over .500"

Gonna need a relatively tight lobe sep (108-109) and an early IVC (103-104 ICL)

It will still pull hard to 6000.

What cam do you have now?

[Walking-Tall]

Congrats on those! What's the cam? Sounds good.

[48fordnut]

Thanks to all for the comments . I was able to get the info I wanted.

WT, it's a Howard. Not much more than a B cam.

[ERStettin]

It is amazing how far the head technology has come since this all started. Those numbers look anemic compared to any aftermarket head out there today and that is good.