[Art]

http://home.isoa.net/~mharrisj/fordhead.html

As I understand, the largest numbers don't necessarily mean the most horsepower.... Smaller, hi-velocity ports improve torque.

 

[Shaun]

Interesting. I'm just about to have a go at porting my 66 289 heads...

Why is it all of the Ford heads suck (or is it wheeze) on the exhaust?? Even the new heads like the GT40P??

 

[Art]

Poor SBF cylinder heads have been a handicap for years before the new aftermarket heads became affordable... Now we have over the counter heads that flow as good as the Chevy heads.

 

[Shaun]

Hopefully I can open up my exhaust a little and save some $$'s for a while...

 

[sidewinder]

I'd have to agree that the numbers don't tell the whole story. I've ran 351C 2v's and the 4v's. If you look the 2v's should kick butt. The 4v's are good for at least 50 HP. The 2v's run out of air at 5000 and the 4v's at about 6500. That's not to say the engine won't turn higher but that's where the power starts to drop off.

 

[sidewinder]

Hey starting in 1970 ford had small block heads that stomped any small block chevy and allmost any big block. Can you say cleveland!

 

[Huskinhano]

www.theoldone.com This site will make you think a second time about porting and chambers!

It also has some very interesting stuff on Bob Glidden and NASCAR!

 

[Guest]

Comparing Cleveland heads to a SBC is like comparing apples to tires! A canted valve head should flow well. There's no way a C head will touch a 10 degree GM. As far as the #'s on the flow page went... guess I did a good job with a sanding roll on my big block Blue Thunders... 361/[email protected] You wanna talk about a head that sucks? try a 73 & later 460. I've seen stock 327 heads do better.

 

[Shaun]

.800 lift?!! That's HUGE!!! Wow!

 

[Guest]

The data is useless unless details of the test are included - especially the pressure drop used in the measurements.

 

[camachinist]

especially the pressure drop used in the measurements.

You'll find it in small print at the bottom of the page ....28" H2O...

 

[CAponyboy]

if you're gonna want good horsepower.......you gotta decide where you want it.....

higher rpms mean a larger port with considerable mods....

Low end torque will call for a gentle massaging of the ports with most of the work in the bowl area behind the valve.

here's another site

www.replikamaschinen.com

a bigger valve DOESN'T always mean more flow and power....

a well set up smaller valve will out flow a larger one due to not being shrouded ....this means it swirls the air better and creates a higher port velocity.....this means a higher cyl pressure...

regards