Porting and Flow testing GT40 heads

[Guest]

[turbo2256]

I run the 1.94 and 1.6 valves in the 40s and DOOE heads exhaust flows in the 190s at .5 lift.

Now if we do a set of E7 heads its the stock DOOE / 40 valve sizes work best.

[jayh]

why no bigger than 1.90? why not 1.94?

[5.0Torino]

I read it somewhere why not to. I can't remember. It may have something to do with the port not being able to go big enough with a 194. You might hit water if you do..

I am just gonna port and flow and port and flow. See where I can mak it to..

[Antony Moore]

Because you cant get the throat to the right percentage and shape the short turn correctly without hitting water. So basically the bigger valve doesnt do anything.

[Outlaw Bill]

Because you cant get the throat to the right percentage and shape the short turn correctly without hitting water. So basically the bigger valve doesnt do anything.

Correct. I used a 1.900 intake valve with a 50/55 deg seat, and a 1.500 exhaust valve size with the standard 45 deg seat. There is no way to "correctly" put a 1.940 valve in the head and and not hit water.

Check out this thread. http://sbftech.com/index.php/topic,25443.15.html

[turbo2256]

Maybe GT40s just wont flow as much as DOOE heads. I will check and see if we use the same program for both heads. Noticed on a friends 40 heads thought there was a dip in the intake port floor I dont remember there being in the DOOE heads. That might screw with the short side. Water jackets might be a bit different.

[jayh]

Because you cant get the throat to the right percentage and shape the short turn correctly without hitting water. So basically the bigger valve doesnt do anything.

Correct. I used a 1.900 intake valve with a 50/55 deg seat, and a 1.500 exhaust valve size with the standard 45 deg seat. There is no way to "correctly" put a 1.940 valve in the head and and not hit water.

Check out this thread. http://sbftech.com/index.php/topic,25443.15.html

yeah I am going to have to respectfully disagree with you there. look around the net the information is there.

[Outlaw Bill]

That is your choice to dissagree. Its possible some castings will allow a 1.940 valve without water injection.

I will ask, whats the purpose of a 1.940 valve if the intake port can't support it correctly?. I have yet to see a iron GT-40/GT-40P head flow above 250 cfm in the real world without expensive mods. Sure with some spray weld and etc I have heard of 270 plus cfm, but they were race only, no street driving due to coolant flow interuptions and etc.

[5.0Torino]

I am gonna say most guys porting GT40 heads are the grassroots type. 90% of us aren't gonna get extremely technical. The guys out there getting 270 out of GT40's are obviously on a different level than myself and others (90%). We don't need to be that technical.

I just start this is a helpfully guideline for future reference for people in the same boat as me. Start from scratch and show gains (or losses) through the whole process and put numbers down with it.

I am gonna be using the 1.84's for the entire test. After the work is done I can still go 1.90's for my own build.

This will be awhile. I am a busy man at times.

[turbo2256]

One issue rarly brought up is the intake manifold. So the heads flow 250 but a ported Vr Jr only flows a bit over 200. Many put 220 cfm heads or more and settle on an intake that only flows 170

[5.0Torino]

The goal for my 332 build is 400FWHP. If it is lower than that I won't be surprised if it meets it or gets higher i'll be tickled pink.

I am using these heads and an Explorer intake. I will also have one for porting and flowing the lower and upper manifold.

I plan on getting the valleys of the lower intake tig welded where they need to be in order to maximize the port design(or lack there of).

I am no expert on porting but I am good at following instruction and anal about my work. I hope make the best of these I can, learn something, and share it with others.

[347HO]

One issue rarly brought up is the intake manifold. So the heads flow 250 but a ported Vr Jr only flows a bit over 200. Many put 220 cfm heads or more and settle on an intake that only flows 170

I don't disagree...  I assume your information is from a flow bench.
I would like to point out that the air column in the intake runner is not continuously flowing on an engine as it is on a flow bench.
So, depending on how well the cam events are setup, when the valve does open...   there's a bit more air per CF which a flow bench can't duplicate.

[jtmustang]

good info here fellas.

question for torino, how much do u have in making the flowbench setup?

thnx

[turbo2256]

One issue rarly brought up is the intake manifold. So the heads flow 250 but a ported Vr Jr only flows a bit over 200. Many put 220 cfm heads or more and settle on an intake that only flows 170

I don't disagree...  I assume your information is from a flow bench.
I would like to point out that the air column in the intake runner is not continuously flowing on an engine as it is on a flow bench.
So, depending on how well the cam events are setup, when the valve does open...   there's a bit more air per CF which a flow bench can't duplicate.

Wont disagree but it can depend on intake volume and RPM. The faster an engine turns it might steal some air from another cylinder.. I use info from a bench but have 100s of engine builds and engine design experance.

[turbo2256]

The goal for my 332 build is 400FWHP. If it is lower than that I won't be surprised if it meets it or gets higher i'll be tickled pink.

I am using these heads and an Explorer intake. I will also have one for porting and flowing the lower and upper manifold.

I plan on getting the valleys of the lower intake tig welded where they need to be in order to maximize the port design(or lack there of).

I am no expert on porting but I am good at following instruction and anal about my work. I hope make the best of these I can, learn something, and share it with others.

I would suggest a different intake. The Explorer intake was dwsigned for low RPM torq. Runner area to plenum area isnt well porportioned for a well built engine. The first Explorer design wasnt bad for performance but Ford ditched it for the released verson.