My statement was half flawed too I made a typo, the exhaust valves are 1.65" not 1.56 as I originally stated.

Here's some before and after pics of the porting I have done so far.We are getting ready to machine the valve job right now and then I will blend things back in and run it on the flow bench to see how we did round 1. Enjoy the pics!

 

Don't mean to hi-jack... but what is the Intake silencer/restrictor that you removed? Thanks

 

Machining the performance valve job:

 

The silencer is a plastic piece located between the throttle body and air box that is connected to the 2 sets of rubber intake hoses. Take a hack saw to the "horns" leaving enough room to still re-connect the rubber hoses.

 

got it. thanks... every little bit has got to help

 

Subscribed. I want to squeak some more HP out of my LIL 460

 

Brad, your truck came to mind when I first started reading this thread. This is exactly what you need to get a little more out of that Vortech'ed 460 of yours!

 

Bo, I am glad you have jumped in here. I have a 95 F250 with a 460. I am having a devil of a time with my engine. I wish you were in Southern IN I sure could use the help. I will be checking your progress daily. Thanks so much for all the info and pictures.

 

Finally got the heads back on the bench and some new flow numbers. I was expecting/hoping for more on the exhaust. We are still at about a 55% flow ratio which is poo-poo IMO, all the intake flow in the world wont make a difference if you can't get it out. I really don't think there is a whole lot more left for improvement in the exhaust port without opening up the cross sectional area and I'm not really interested in blowing into a water jacket to find out how much further they can go! Based off the flow characteristics of the port it could definitely use some more curtain area which a larger valve would provide. I am thinking the most realistic option at this point to further increase flow up to a respectable amount is to jump up to 1.76" exhaust valves, which means more than likely new valve seats as well. No big deal, but an extra cost to the job. We will see if the gains from the larger valve are worth it. I am also going to upgrade the intake valves to a 2.19" to try and harness some of the port's current high lift flow capabilities at a realistic valve lift. We will see soon! Here are the specs again and current results:

F3TE casting (EFI) Stock/Ported.
Stock 2.09" IN / 1.65" EX valves (intake back-cut 30*)
28" H2O depression
1/2" clay radius on intake, no pipe on exhaust
4.25" test bore
SF600 flow bench calibration

Intake Flow Data:

Valve Lift---Stock IN Flow---Ported IN Flow
.100"------------58.2----------69.9
.200"------------122.3---------132.3
.300"------------176.4---------198.5
.400"------------214.7---------250.4
.500"------------240.6---------274.0
.600"------------249.7---------284.2


Exhaust Flow Data:

Valve Lift---Stock EX Flow---Ported EX Flow
.100"-----------44.7------------45.9
.200"-----------85.8------------86.4
.300"-----------109.9----------115.6
.400"-----------124.4----------136.6
.500"-----------133.4----------150.8
.600"-----------141.8 ---------159.1

 

Wow yeah your right, exhaust didnt improve for chit. Great to see this, kinda makes ya wonder what ford was thinking when the designed these things initially...

 

After some thought last night I decided to go even bigger on the exhaust side with a 1.80" valve from Ferrea. The valve has a steep underhead angle of 25* which typically helps in a port like this in addition to the increased diameter. I also order the 2.19" intake valves from Ferrea. Even at 1.76 we would have had to change the exhaust valve seats to properly fit the valves so if we are upping the seat size anyway I thought we would go up a size on the valve. Should have flow updates early next week, for now we will be waiting on parts.

 

This is a pretty sweet thread and thanks for posting it! It makes you wonder, with the right type of equipment, what can you really get out of one of these engines with a little skill and not too much trouble. I do have a question though. Is there any certain CFM that your trying to achieve as compared to the cylinder size? 460/8=57.5 so is there a certain CFM that would be perfect for a 57.5 CI cylinder volume and do you have to take into account the combustion chamber size and compression ratio? Also, if you have a set cylinder volume, does the flow value that your trying to achieve change with compression ratio? What i'm trying to ask is, in the buisness of cylinder heads and porting, is there a magical number that you try to go by that makes the most power or is it more trial and error? I hope i'm not asking too many crazy questions. lol. Thanks!

 

Yeah. I know. Just another thing to add to the to do list

 

Bo, welcome to FTE and thanks for an awesome thread. I am staying glued to this one. Once all the R and D is done, I would love to have a figure on the cost of your headwork. My trucks engine is getting tired and is gonna need a refresh here soon. I was playing around with the idea of getting head work while it was apart. Thanks

 

got my attention!