Don Terrill’s Speed-Talk

[quote="thomas butt"

- Have guys done this with a 4v head? Would be interesting to see power potential of a properly ported 4V with a 2.12 or 2.15 valve and even 1.6 exhaust (if possible)[/quote]

Ford actually made that combination in 1973 or so for some application, a large 4V port, open chamber and the 2V size valves 2.040 1.650. My data on a 4.030 bore is this:

D3ZE head:

INT
.100 59
.200 136
.300 181
.400 226
.500 262
.600 285
.650 289
.700 285

EXH
.100 51
.200 98
.300 135
.400 162
.500 174
.600 182
.700 183

DaveMcLain wrote:[quote="thomas butt"

- Have guys done this with a 4v head? Would be interesting to see power potential of a properly ported 4V with a 2.12 or 2.15 valve and even 1.6 exhaust (if possible)

Ford actually made that combination in 1973 or so for some application, a large 4V port, open chamber and the 2V size valves 2.040 1.650. My data on a 4.030 bore is this:

D3ZE head:

INT
.100 59
.200 136
.300 181
.400 226
.500 262
.600 285
.650 289
.700 285

EXH
.100 51
.200 98
.300 135
.400 162
.500 174
.600 182
.700 183[/quote]

Good info! Looks like the smaller exhuast really helped at .200 &.300. I'd like to see one ported

Seems like intake valve needs to stay big.

Anybody know the details of Ronnie Crawfords 310" boss motor?

what intake are you going to run? have you decided on how much stroke you are going to do?

Hi

Where is the intake port minimum cross sectional area in the 4V CC or OC cast iron celevand heads positioned ?

and

What is the minimum cross sectional area measurement ?

thanks

cab0154 wrote:what intake are you going to run? have you decided on how much stroke you are going to do?

Intake: Edel 2861. Probably 3.7" using stock crank

Buggar no one knows where the standard 4V CC or OC MCSA is from the factory , I'm about to start improving my 4V CC factory cast irons so as this thread is titled " Re: Looking for a few tips on porting 351c 4v heads".

They ( 4V's ) are definitely are to large for a 351C@7000RPM with a port entrance area of 4.53insq and feeding a 2.19 diameter intake valve.

I have ordered some mold casting rubber and will have to do it the old method cut and slice and graphpaper it. With all the people out there with their new CNC porting machine you would think someone has digitised the a full set of standard factory cast iron 4V's and one could look at prity pictures n 2D/3D and share that information.

Here is my attempt to 3D draw a 4V port , i failed art classes at school , fill in the missing blanks if you know any of the standard port dimensions onto my drawing.

I have done a many simulations in PipeMax - MaxRaceSoftware Larry Meaux's and some very interesting results.

What the actual number is I can't even remotely remember.. but the MCSA is at or just dropping over the apex of the SSR. Unfortunately there is just not enough material to fix it completely with a big valve size and stay out of water. You can really help port stall and turbulence issues with very small valvestems/guides/and additional guide boss streamlining. Many just cut out the factory iron guide bosses altogether for max effect.

A smaller valve can help matters because then you have more lattitude to build a more efficient shape on the short side. Valve curtain area gets smaller but the port gets better to more than make up for the loss in valve size. Hope that helps at all.

groberts101 wrote:What the actual number is I can't even remotely remember.. but the MCSA is at or just dropping over the apex of the SSR. Unfortunately there is just not enough material to fix it completely with a big valve size and stay out of water. You can really help port stall and turbulence issues with very small valvestems/guides/and additional guide boss streamlining. Many just cut out the factory iron guide bosses altogether for max effect.

A smaller valve can help matters because then you have more lattitude to build a more efficient shape on the short side. Valve curtain area gets smaller but the port gets better to more than make up for the loss in valve size. Hope that helps at all.

Awesome info. Thanks. Here is a pic of a D3 intake port where the floor is angled. Why the angle? Better swirl?

What is that a spy photo taken with an 80's cuff link camera?

If you look at a 4v port it makes a turn around the pushrod and widens to the left a great deal (port get shorter yet wider before the bowl). it seems like none of the port fillers, tongues, take the widened section into consideration? They fill the front part of the port but taper by the time the floor starts the short turn...

Totally different ports.

piston guy wrote:Totally different ports.

I am talking about a 351c 4v port only

The head began life in late '67. While they did have flowbenches to test with , the ports left alot to be desired. Race versions of the head( Trans Am heads) had the ports rewroked over "production" versions and made more power accordingly. Most of these heads were used up in Nascar engines and Pro Stock racers were left with the production heads. Lots of "Devcon" was used to make them flow. Ford's series of aluminum high port castings were superior almost out of the box.
Iron heads have always been very exhaust system dependent and require split duration camshafts to help the extreme flow bias. High port plates helped but didn't eliminate the problem.

Kazoom wrote:in 69-70 Ford Indy designed removable/changeable intake port inserts for the 4V head for Trans-Am racing for more velocity with the Small 302ci eng...

http://www.ponysite.de/transam_stevens3.htm

Port inserts were not SCCA legal. The heads pictured are T/A heads and as I mentioned far different than production heads. There was also a "small port" head created for 1970/71 use that featured "filled" intake ports. I have Bud Moore engine build sheets that note their use and the comments are not great. Power was down on them and few were used. Some raw castings are "floating around" and may never finish machined.

Why does the port shape here http://www.ebay.com/itm/Ford-302-351C-C ... 1935937328 look drastically different then what you have pictured? I understand it's the "speedmaster" brand but AFAIK speedmaster and procomp are one in the same.
Here's a question for you, what ever happened to the procomp electronics website?

More importantly, why is it that most professional builders won't reccomend using those brands versus other options, and a large number would reject using them altogether? Why does it seem that there are more horror stories regarding the use of those brands then praise/achievements? Also, why is it that you find everybody who contradicts you as a troll?