First I have to say this Is a great Fourm you have here Don. Very helpful.
I have a set of 351w DOOE casting that I ported(60hrs or more) 5 years ago. They flowed 230 cfm @ .500 lift then started backing up above .500 lift. These are on a 3200# 67 Mustang, 310cid, C4, 9" radial slick, 5:14 gear. The best I got it to run was 11:07 @ 119mph. Shifting at 7200
This year I decided I wanted to get it in the 10s. With the help of a sonic tester. And another 60hrs or so of porting and testing. I feel I have got these heads about as good Im going to get them with my lack of knowledge.
One thing I am afraid of is the small port cross-section of 1.94 SQin just .250 before the short turn. So I figured what my flow would be at 45"water. They flowed exactly that at 45".
here is a picture of my port mold with SQin dim. I messed up on this picture the 2.40 just before the seat measures 2.54 SQin.
http://pg.photos.yahoo.com/ph/brady6414 ... pg&.src=ph
http://pg.photos.yahoo.com/ph/brady6414 ... pg&.src=ph
One of the problems I am having is getting a 30* backcut to work at .500 lift
Flow chart @28" with 3/4" plastic inlet with 1/2" radis. and 2" exh. pipe.
35* backcut
.100 68 57
.200 125 110
.300 179 150
.400 219 181
.500 251 182
.550 258
.600 255 182
.700 239 186
30* backcut
.100 70
.200 136
.300 187
.400 226
.500 247-260 varies
.600 244
.700 247
My questions are 1)Do my port volumes and shape look like I will have any problems? 2)If not, do you think they will support 7700-7800 shift points? 3)Is it normal for this type of head to not have a defined throat area next to the valve(mine is smaller then the seat but bigger then the SST)
4.040" Bore
3.021" Stroke
2" Valve
1.800 throat 90% I belive
Minimum CA 1.94 (almost half way down the port) I do have room to increase this area but don't think I want to lose the taper from intake to SST.
Thanks for any help. I only need a tenth to get in the 10s
sbf head
Moderator: Team
The cam I have been running is Comp Cams Magnum mechanical roller .613x.613 lift, 264x264 @.050", and 110 LSA.
Tim Cole from Comp picked out some lobes and sent me. *takes a deep breath* .696 x .673 lift, 267 x 273 @.050" with 107 LSA
I got the new cam a few years ago but didnt install cause of the lack of air flow above .500 lift
Tim Cole from Comp picked out some lobes and sent me. *takes a deep breath* .696 x .673 lift, 267 x 273 @.050" with 107 LSA
I got the new cam a few years ago but didnt install cause of the lack of air flow above .500 lift
Darrell
67 Mustang 3000# 310ci NA 10.17 130.5mph,1.36 60'
67 Mustang 3000# 310ci NA 10.17 130.5mph,1.36 60'
-
bill jones
- Guru
- Posts: 2650
- Joined: Sun Sep 05, 2004 6:38 pm
- Location: salt lake city, ut
- Contact:
I run a Victor Jr intake. It was gasket matched before I got it.
I want to flow with the intake manifold on. But not sure what I would look for or change if I did.
Carb is a 650 Holley with 850 base plate. and 1" open spacer.
The headers are just Hooker 1 5/8''. I see Headman is comming out with some bigger headers this year for the early Mustangs.
I want to flow with the intake manifold on. But not sure what I would look for or change if I did.
Carb is a 650 Holley with 850 base plate. and 1" open spacer.
The headers are just Hooker 1 5/8''. I see Headman is comming out with some bigger headers this year for the early Mustangs.
Darrell
67 Mustang 3000# 310ci NA 10.17 130.5mph,1.36 60'
67 Mustang 3000# 310ci NA 10.17 130.5mph,1.36 60'
I think that at 7200 RPM you are almost out of cross section. Making some manifold changes (flowing head w/manifold) would be a GREAT idea.
I also think that the cam area does need some work. But I would recommend that you try the other Comp stick you have.
Good Luck!
I also think that the cam area does need some work. But I would recommend that you try the other Comp stick you have.
Good Luck!
Jay Allen
CAMSHAFT INNOVATIONS
www.camshaftinnovations.com
CAMSHAFT INNOVATIONS
www.camshaftinnovations.com
-
buddy rawls
- Member
- Posts: 187
- Joined: Wed Mar 24, 2004 4:38 pm
- Location: North Alabama
what is your average intake port volume across all the ports? by the numbers you are probably around 158-165 ccs.
What is your static compression?
A peak hp around 7000 is going to be about the limit (assuming 351W casting with ~162ccs). revving and shifts are going to take it over this, but it will start signing off as you get nearer to 7500.
The help is going to come from better ramp rate, without compromising seat duration and better lobe placement.
basically a duplicate of what Jay Allen said, sorry about that
What is your static compression?
A peak hp around 7000 is going to be about the limit (assuming 351W casting with ~162ccs). revving and shifts are going to take it over this, but it will start signing off as you get nearer to 7500.
The help is going to come from better ramp rate, without compromising seat duration and better lobe placement.
basically a duplicate of what Jay Allen said, sorry about that
Buddy Rawls
Cross Section Engineering
Cross Section Engineering
-
bill jones
- Guru
- Posts: 2650
- Joined: Sun Sep 05, 2004 6:38 pm
- Location: salt lake city, ut
- Contact:
-If the heads were mine I'd be looking at enlarging from the 2.14 clear out to the gasket.
-I don't like that 1.94 at all.
-I would also bolt the heads onto the block, get the manifold bolted to it, then make some reference marks across the manifold-the gasket-the heads at all four corners.
-What I do there is at the four corners is they are usually pretty close at aligning up between the heads and the manifold there but I grind each corner so they are perfectly aligned and smooth across the joints and the installed gasket.
-This means that when you run your fingers across the front or rear of each end at the manifold gasket you have a nice smooth flush surface at each of the four corners.
-Then I take a thin cutoff wheel and I cut a thin witness line across these four corners.
-Now when you take the manifold off and you remove the gaskets, you have the gaskets as templates and the witness marks to get the alignment dead nuts.
-----------------------------------
-I would also get as tall a 4 hole spacer as you can run, one that fits the throttle bores perfect, then blend from the bores to the plenum walls of the manifold, then blend the center into an upside down pyramid shape where the point of that pyramid is shortened (raised up 1/3rd) to about 2/3rd of the total spacer height.
-At least try one until you prove whether it does anything or not.
-I have seen lots of times where a four holer like this is worth well more than a tenth on a 1/4 drag strip (at 4200 elevation).
------------------------------------
-How wide is the port between the pushrods?
-How wide is the pushrod holes apart? top and bottom of the head?
-What are you running for pushrods diameter?
-What is the diameter of your pushrod holes?
-Have you looked at the position of the pushrods within the pushrod holes on the assembled engine?
-Usually there is a lot of room to widen the port, particularly on the left side wall where you have the largest pushrod bulge.
-If you don't have those pushrod walls at .015" thin you need to get that figured out.
-------------------------------------------------
-BUT---I would consider in a big way to sleeve the pushrod holes with thinwall brass tube that you press into a "D" shape and then epoxy in there with the flat side of the "D" towards the portwalls, then cut the portwalls clear out to the brass.
------------------------------------------------
-When you flow the manifold just worry about high lift flow.
-Like adjust each port to flow something like 250 with the radius inlet, then remove the inlet and install the manifold and flow both runners of the manifold that fit that port by turning the manifold around and doing both sides.
-You have to have all the valves in the head, and you have to seal off the four ports that are not against the head, and yoiu should have the carburetor and the spacer on the manifold.
-What you will find is the longer end runners flow less than the short center runners so you need to work on getting some better equality.
-You'll never see that same 250cfm in any of the eight (2000 total) so you try to help the poorer flowing ports to get better averages and try to get the totals closer to 2000.
--------------------------------------------------
-Regardless I don't think the engine will ever pull hard to 7800rpm with the cast iron heads but you can help it a lot.
-I don't like that 1.94 at all.
-I would also bolt the heads onto the block, get the manifold bolted to it, then make some reference marks across the manifold-the gasket-the heads at all four corners.
-What I do there is at the four corners is they are usually pretty close at aligning up between the heads and the manifold there but I grind each corner so they are perfectly aligned and smooth across the joints and the installed gasket.
-This means that when you run your fingers across the front or rear of each end at the manifold gasket you have a nice smooth flush surface at each of the four corners.
-Then I take a thin cutoff wheel and I cut a thin witness line across these four corners.
-Now when you take the manifold off and you remove the gaskets, you have the gaskets as templates and the witness marks to get the alignment dead nuts.
-----------------------------------
-I would also get as tall a 4 hole spacer as you can run, one that fits the throttle bores perfect, then blend from the bores to the plenum walls of the manifold, then blend the center into an upside down pyramid shape where the point of that pyramid is shortened (raised up 1/3rd) to about 2/3rd of the total spacer height.
-At least try one until you prove whether it does anything or not.
-I have seen lots of times where a four holer like this is worth well more than a tenth on a 1/4 drag strip (at 4200 elevation).
------------------------------------
-How wide is the port between the pushrods?
-How wide is the pushrod holes apart? top and bottom of the head?
-What are you running for pushrods diameter?
-What is the diameter of your pushrod holes?
-Have you looked at the position of the pushrods within the pushrod holes on the assembled engine?
-Usually there is a lot of room to widen the port, particularly on the left side wall where you have the largest pushrod bulge.
-If you don't have those pushrod walls at .015" thin you need to get that figured out.
-------------------------------------------------
-BUT---I would consider in a big way to sleeve the pushrod holes with thinwall brass tube that you press into a "D" shape and then epoxy in there with the flat side of the "D" towards the portwalls, then cut the portwalls clear out to the brass.
------------------------------------------------
-When you flow the manifold just worry about high lift flow.
-Like adjust each port to flow something like 250 with the radius inlet, then remove the inlet and install the manifold and flow both runners of the manifold that fit that port by turning the manifold around and doing both sides.
-You have to have all the valves in the head, and you have to seal off the four ports that are not against the head, and yoiu should have the carburetor and the spacer on the manifold.
-What you will find is the longer end runners flow less than the short center runners so you need to work on getting some better equality.
-You'll never see that same 250cfm in any of the eight (2000 total) so you try to help the poorer flowing ports to get better averages and try to get the totals closer to 2000.
--------------------------------------------------
-Regardless I don't think the engine will ever pull hard to 7800rpm with the cast iron heads but you can help it a lot.
Port Volume? 160cc Good guess Buddy Rawls When I ran these heads last time they flowed in the 230s at 155cc.
How wide is the port between the pushrods? It's 1.250 with a brass tube on the left side. and roughly .060" on the right side.
When you flow with the manifold on you have to have all the valves in the head? Can I just tape the three other ports off like the other side? or will that give false readings?(I will have to get more soft springs then)
I have a 2'' tall 4 hole spacer I will modify as you suggested.
same pic as above
http://pg.photos.yahoo.com/ph/brady6414 ... pg&.src=ph
The roof area between the 1.94 and 2.14 is about .080" thick. Do I dare go thinner? Im sure it depends on how much wider I made the port in that area too.
How wide is the port between the pushrods? It's 1.250 with a brass tube on the left side. and roughly .060" on the right side.
When you flow with the manifold on you have to have all the valves in the head? Can I just tape the three other ports off like the other side? or will that give false readings?(I will have to get more soft springs then)
I have a 2'' tall 4 hole spacer I will modify as you suggested.
same pic as above
http://pg.photos.yahoo.com/ph/brady6414 ... pg&.src=ph
The roof area between the 1.94 and 2.14 is about .080" thick. Do I dare go thinner? Im sure it depends on how much wider I made the port in that area too.
Darrell
67 Mustang 3000# 310ci NA 10.17 130.5mph,1.36 60'
67 Mustang 3000# 310ci NA 10.17 130.5mph,1.36 60'
-
bill jones
- Guru
- Posts: 2650
- Joined: Sun Sep 05, 2004 6:38 pm
- Location: salt lake city, ut
- Contact:
-The whole idea of flowing the manifold is to flow every hole.
-It sounds like maybe you haven't even been flowing all of the head ports yet?
------------------------------------
-If you load the heads with all the valves then you can use each of the head ports to flow two of the manifold ports.
-It sounds like you have a handle on the pushrod width.
------------------------------------
-the .080" thick or thin area, is there water above it or does it break thru into the valve spring area?
-It is because of 302 and 351W Fords that I had to learn how to braze heads so maybe you and Bos need to think about the possibilities what you can do if you took on the challenge of brazing the heads.
-------------------------------------
-When you are looking for more rpm you need to increase the port square inch area by about .1 for each 200 to 300 rpm for a small engine like that.
-If you cut the entire roof width say .050" so that all you had left was .030", that would have a lot of surface area that could break.
-But if you cut a pair of troughs and left a rib in the center then that rib would be some major strength.
-----------------------------------
-At our oval track they had cast iron manifolds as mandatory and you couldn't port'm.
-But they didn't say anything about machining the weight off the manifold so I machined the outside of the intake ports with a ball end mill and cut some pretty serious grooves everywhere including the top and the valley side of the port runners.
-We lightened that manifold 40% and it was really flimsy but it never sucked a wall in and it never cracked anywhere.
-Didn't do much good because as soon as they saw what we'd done to the top side it was outlawed.
-We had also done the same exact thing to the heads, just to remove weight and we never had any water leaks with the ribs left in there.
-But we got smart and didn't cut anywhere that prying eyes could see what we'd done so we ran those heads for several years.
-It sounds like maybe you haven't even been flowing all of the head ports yet?
------------------------------------
-If you load the heads with all the valves then you can use each of the head ports to flow two of the manifold ports.
-It sounds like you have a handle on the pushrod width.
------------------------------------
-the .080" thick or thin area, is there water above it or does it break thru into the valve spring area?
-It is because of 302 and 351W Fords that I had to learn how to braze heads so maybe you and Bos need to think about the possibilities what you can do if you took on the challenge of brazing the heads.
-------------------------------------
-When you are looking for more rpm you need to increase the port square inch area by about .1 for each 200 to 300 rpm for a small engine like that.
-If you cut the entire roof width say .050" so that all you had left was .030", that would have a lot of surface area that could break.
-But if you cut a pair of troughs and left a rib in the center then that rib would be some major strength.
-----------------------------------
-At our oval track they had cast iron manifolds as mandatory and you couldn't port'm.
-But they didn't say anything about machining the weight off the manifold so I machined the outside of the intake ports with a ball end mill and cut some pretty serious grooves everywhere including the top and the valley side of the port runners.
-We lightened that manifold 40% and it was really flimsy but it never sucked a wall in and it never cracked anywhere.
-Didn't do much good because as soon as they saw what we'd done to the top side it was outlawed.
-We had also done the same exact thing to the heads, just to remove weight and we never had any water leaks with the ribs left in there.
-But we got smart and didn't cut anywhere that prying eyes could see what we'd done so we ran those heads for several years.
When using *Average Cross Section* I have begun to see "trends".d64falcon wrote:When I ran these heads last time they flowed in the 230s at 155cc.
155cc = 1.8914 sq in (avg)
We'll use 235 cfm
235/1.8914 = 124.25 cfm/sq in
IMHO if you increase the CFM at this point w/o significantly increasing the area, you will not see an increase in performance.
Jay Allen
CAMSHAFT INNOVATIONS
www.camshaftinnovations.com
CAMSHAFT INNOVATIONS
www.camshaftinnovations.com