I'm going to try to port a set of 333 heads and am looking for some tips on doing this especially pictures showing the best areas to gain usable flow,I am looking for improvement that won't require super high lift (more than .575)or high rpm(greater than 6000-6500 rpm) on a 427-440 inch stroker.I don't plan to do much to the floors of the ports since they don't typically help much.I am hoping to use 2.19-1.72 valves my machinist has already said he would rough cut the seats and throat and finalize after the porting.I have seen comments where opening the throat for larger intake valves actually gives a less advantageous short turn is this true if so would it be better to hand open the throat avoiding the short turn area?I also have seen comments about the top of the port near the intake bolt about not changing the taper of the port width.What are the don'ts regarding this area?I also saw a post of someone that had cut a 333 head into 8 pieces if they could post pics showing the thickness in the cross section of the intake and exhaust ports and pics showing the thickness of the area under vale spring seats that would be awesome.
Porting 333 heads
- Thread starter 427John
- Start date
I posted this before:
Do not take any material off the floor. Open the area below the seat to about 90% of the valve size on the intake. The area on either side of the guide can be deepened. The guide boss can be narrowed and the boss can be shortened where it extends into the intake port. Do not remove the material behind the guide as it likely just p!ss it off. Make the pinch area next the push rod as wide as possible and blend that back into the port. You can stream line the leading edge of the guide boss, but it really wont do anything. There really isn't much you can do with the short turn radius. Just make sure it is a smooth transition. If you want, you could lay it back a little to gain volume in the bowl area. Use a valve that is "flat" on the backside for the intake. Not much to do on the exhaust but narrow the guide boss, a port match, and blend the valve job. You can also round the edge of the exhaust valve on the face side. A drill press and a fine file will do this nicely. Make sure you still maintain .060 at a minimum on the margin. A little goes a long way and can be worth a surprising amount relative to the size of the change. I'll post pictures of my 690s later.
I would amend that to be 88% of the valve size. If you can, mock up everything so you can see how your intake matches to the head ports. You don't want the port in the head smaller than the intake manifold. A little larger won't hurt. Take measurements where you can so all the ports come out the same. And remember, on iron heads it is a long process. Whatever you do once, you'll have to do 7 more times!
Do not take any material off the floor. Open the area below the seat to about 90% of the valve size on the intake. The area on either side of the guide can be deepened. The guide boss can be narrowed and the boss can be shortened where it extends into the intake port. Do not remove the material behind the guide as it likely just p!ss it off. Make the pinch area next the push rod as wide as possible and blend that back into the port. You can stream line the leading edge of the guide boss, but it really wont do anything. There really isn't much you can do with the short turn radius. Just make sure it is a smooth transition. If you want, you could lay it back a little to gain volume in the bowl area. Use a valve that is "flat" on the backside for the intake. Not much to do on the exhaust but narrow the guide boss, a port match, and blend the valve job. You can also round the edge of the exhaust valve on the face side. A drill press and a fine file will do this nicely. Make sure you still maintain .060 at a minimum on the margin. A little goes a long way and can be worth a surprising amount relative to the size of the change. I'll post pictures of my 690s later.
I would amend that to be 88% of the valve size. If you can, mock up everything so you can see how your intake matches to the head ports. You don't want the port in the head smaller than the intake manifold. A little larger won't hurt. Take measurements where you can so all the ports come out the same. And remember, on iron heads it is a long process. Whatever you do once, you'll have to do 7 more times!
Don you must have me confused with someone else I'm not going to run a blower,just a tripower or possibly a single 4 if edelbrock makes an intake to work with small port heads.I mainly want to make sure I'm getting everything I can out of the 333's without a full race port and polish job they can cause their own problems for street use.
shiftem do you have any insight how thick the area at the pushrod pinch is? Breaking thru there won't be a relatively easy fix like on heads that don't guide the rocker with the pushrod.Any maximum width measurement from the opposite port wall would be extremely helpful if you have it.
No not off hand. You can feel how thick it is there since there is no water on that area. Just keep the cutter perpendicular to the gasket surface, widen that small narrow area, and then blend it in. The hole that guides the push rod is higher than the port so there is no issue there.
I do the 2.19/1.72 seats with the Serdi cutter in one operation. (333's 0r 817's) Then plug the bolt hole between the ports with a cast iron plug and red or green loctite. (Have also used soft grade two steel bolt for the plug) You can now port into the sides of the plug and remove the restriction. Finish the surface on the mill or use a file. On one set of heads I drilled and tapped holes for grade eight 1/4" bolts just above the original 3/8" bolt location. This provides some clamping, but if you position the 1/4" hole so the bottom of the hole just intersects the top of the plug, it locks the plug from ever turning and getting loose. You can safely remove a little more metal from the sides of the plug. The bowls on these heads are pretty good size (unlike the 379's) and the pushrod pinch area is of course the initial restriction. You can make a tool (I have one somewhere) for checking the wall thickness on the pushrod pinch. Or use dividers, and count turns on adjustment wheel to see the actual thickness. Sometimes I use a sonic tester to check this area while porting heads, just for convenience. Just some different ideas.
Just keep in mind that it is better to back off a little than make holes. Iron isn't easy or cheap to repair. I've made holes in two heads and repaired them so I know 
. A sonic checker would be handy for sure. There are areas in my heads I would like to work more but, I have backed off for fear of the unknown.
. A sonic checker would be handy for sure. There are areas in my heads I would like to work more but, I have backed off for fear of the unknown.
I didn't get too crazy with mine when I ported them and cleaned them up. I basically did a gasket match first and tapered the opening into the runner. I ground off the casting marks and left the walls, ceiling and floor somewhat rough. Finished with coarse sandpaper on a drum using the Dremel.
On the valve side, tapered the valve guide bosses to a bullet shape, opened the valve opening and blended that into the throat. Again, no polish here. Coarse finish. Spent time on the short turn radius cleaning it up and blending the runner into the valve throat area but nothing crazy. I think most of the performance on the 333s comes from a precision gasket match and runner blending, the bigger intake valves (2.19) and general clean up. I'm no pro but my heads performed awesome on the dyno bolted on my 416" 409
On the valve side, tapered the valve guide bosses to a bullet shape, opened the valve opening and blended that into the throat. Again, no polish here. Coarse finish. Spent time on the short turn radius cleaning it up and blending the runner into the valve throat area but nothing crazy. I think most of the performance on the 333s comes from a precision gasket match and runner blending, the bigger intake valves (2.19) and general clean up. I'm no pro but my heads performed awesome on the dyno bolted on my 416" 409
Were you able to fix them by tubing the hole up to the bottom of the guide hole or did you have to weld or epoxy them,also the flat valves you mention in your first post are all replacement stainless 409 valves like that or do you have to stick to a certain brand.Just keep in mind that it is better to back off a little than make holes. Iron isn't easy or cheap to repair. I've made holes in two heads and repaired them so I know
I'm not sure anyone has tried yet but I don't think it would be too hard. My engine ended up at 10.2:1 compression. Stock stroke, Diamond pistons, Eagle rods, solid flat tappet cam and 333 casting heads on a truck block. Mine made 473hp honest horsepower in mid July in Missouri in mega humid air (91 degrees at the time of the pull) on 91 octane. So I think even with better fuel and 60 degree temps mine would be 15hp higher
Getting close. 11:1 compression, a splash of race fuel (and no ethanol), maybe one cam size larger than mine and it should do it...500hp is most definitely doable with a truck engine. I've got some parts set aside for a future project with my son when he gets a little older and was thinking of building something similar to my engine but perhaps with a roller cam, FAST or Holley EFI, stock stroke etc and stuff it into a 63-64 Chevy shortbox pickup. 5 Speed etc.Don I was reading the thread on using BBC valves in w heads and got some confusing info,they talk about using BBC intakes that are around +.100 and using pontiac exhaust 1 guy saying RAIV which is around the same length as the BBC intake while another guy says D port exhaust which is a little shorter than stock 409,this leaves 2 different spring installed heights unless they are talking about not using rotator eliminators on the exhaust side and shimming height to match the intake.This should leave rocker geometry close to stock on the exhaust while requiring some adjustment on the intake,am I reading this right or am I missing something?This would also make the valve spring choices much larger,making it fairly easy to get to a 1.800 installed height.
I'd have to defer to Dan,Dave,or some of the other race engine guys about that type of switching of the parts around like that,and the problems that entails.A few years back I was talking to Ronnie Russel about using big block valves,and he said that he'd done it,but that it made getting the geometry right a real pain in the butt.I would never question him given his experience and expertise with these engines.With the amount of lift you're planning,an assembled height of around 1.74 will be all that would be needed.Any thing else for a street engine would ,in my opinion,be a waste of time and money by making things more complicated than is needed for a good running,long lasting street engine.
Ferrea Valve Catalog has lots of options for high quality valves. They stock a 1.77" Pontiac application valve that works out. Sourced some good 1.81" exhaust valves from Brodix awhile back. Have used BBC valves also. Yes they are a little long, but if you have a big roller you have to find some room somewhere for spring height. (Hate deepening spring pockets, or using +.050 keepers). The goofy rocker stud angles make setup a pain. Screw-in rocker studs that are extra long help. As Don mentioned, Competition Products has lots of decent parts available, and good pricing, too.
When you're shopping for valves for a hot rod build, think head and stem diameter, length that will let you get the required spring in there, and material type (for needed strength and valve guide material compatibility), instead of for a specific engine model. Beehive springs are great, but I would use only the very best quality spring. If that single spring breaks...
All old news to some, maybe a help to some.
When you're shopping for valves for a hot rod build, think head and stem diameter, length that will let you get the required spring in there, and material type (for needed strength and valve guide material compatibility), instead of for a specific engine model. Beehive springs are great, but I would use only the very best quality spring. If that single spring breaks...
All old news to some, maybe a help to some.