Carb and Pump Issues
Old School Hot Rodder
Joined: Feb 2006
Posts: 6,472
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From: Exmore, VA
It looks like someone jetted Bruno's a little richer on the primary side and screwed the secondary side up totally by changing the clusters. I would love to find all the tuning information for these even though I have always preferred Holley on a Ford.
FTE Legend
Joined: Jul 2010
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From: Northeast, OK
The secondary boosters/venturii.
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Postmaster
Joined: Nov 2009
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From: Broken Arrow , OK
Bruno put different rods in to Edelbrock's recommendation.
I still dont think the cam is right either. I just dont see it doing what I wanted it to do. The cam doesnt come in until 1600 RPM with 3:73 ratios. My truck has 3:50 ratios so it actually comes in later than that. My F 250 runs a lot stronger than the Bronco does. My neighbor James has a 1986 F 150 that has an EFI 302 with a 351W computer in it. I think his truck will eat the Bronco alive in a drag race. I am talking about several car lengths too. I am too embarassed to line it up with him after all the money and mods I put into the Bronco. This thing should be pinning you back in the seat and barking the tires between gears.
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Joined: Jul 2010
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From: Northeast, OK
Yes, that was Art at Edelbrock's recomendation. He was trying to mimick the secondaries of the 1405. However, the bleeds are different and at least one other dimension of the venturis in the rear. So it didnt work out like it should have. The 1405 has a lot more ummphh when the secondaries come in compared to the 1406 with my set up.
I still dont think the cam is right either. I just dont see it doing what I wanted it to do. The cam doesnt come in until 1600 RPM with 3:73 ratios. My truck has 3:50 ratios so it actually comes in later than that. My F 250 runs a lot stronger than the Bronco does. My neighbor James has a 1986 F 150 that has an EFI 302 with a 351W computer in it. I think his truck will eat the Bronco alive in a drag race. I am talking about several car lengths too. I am too embarassed to line it up with him after all the money and mods I put into the Bronco. This thing should be pinning you back in the seat and barking the tires between gears.
I still dont think the cam is right either. I just dont see it doing what I wanted it to do. The cam doesnt come in until 1600 RPM with 3:73 ratios. My truck has 3:50 ratios so it actually comes in later than that. My F 250 runs a lot stronger than the Bronco does. My neighbor James has a 1986 F 150 that has an EFI 302 with a 351W computer in it. I think his truck will eat the Bronco alive in a drag race. I am talking about several car lengths too. I am too embarassed to line it up with him after all the money and mods I put into the Bronco. This thing should be pinning you back in the seat and barking the tires between gears.
However, you do have a LOT of cam in there. The vacuum gauge says you have way more than in Rusty as we got ~15" of vacuum on your Bronco and I get almost 18" on Rusty - with the same gauge. And yours give wild swings of the needle from the same port of the same carb that Rusty's wiggles some. So, unless your ignition timing is very slow, and that is also one thing we have to ascertain, then you are running a lot of cam.
Another thing we can try is to put my 4160 Holley on there. It seems to be jetted pretty fat, so it might be a fair match for your engine. However, with no kickdown linkage you'll have to manually shift the C6, but that's no biggee for testing.
Don't give up just yet. I'm convinced the basic engine is sound. Once you get the header leak fixed and pick up the 1405 we can make another stab at it and I'll bet we see some serious progress.
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Postmaster
Joined: Nov 2009
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From: Broken Arrow , OK
Bill here is the engine:
And here are the roller cam specs:
My machinist thinks the engine should be putting out around 9 or 9.1:1 compression ratio.
I built a 351W that went 0.30 over forged pistons,fully balanced lower end, full roller top end, windsor senior heads, 202-160 valves, 200 cc intake runners, 64 cc combustion chambers, 64 cc exhaust ports, a nice off road cam, edelbrock performer dual plane intake and 1406 edelbrock performer 600 cfm 4bbl carb,short tube headers, true duals with no cats, MSD ignition module, blaster coil, and pro comp distributor.
SBF - Street Beast 09 - HR110 + 4°
Reccomended valve adjustment: Intake .000" - Exhaust .000"
Lobe lift: Intake .353" - Exhaust .353"
Gross valve lift 1.60 ratio: Intake .565" - Exhaust .565"
Duration @ .050" tappet lift: Intake 214° Exhaust 224°
Lobe seperation: 110°
Recommended Intake centerline 106°
Valve timing at .050" tappet lift: _ open ___________ close
____________________ Intake: 1° BTDC __________ 33° ABDC
__________________ Exhaust: 46° BBDC ______ -2° ATDC
Degree this camshaft, using the specs provided on this sheet. The asymmetrical design of these lobes may not allow for accurate reading using the centerline method.
This camshaft is designed for naturally aspirated high torque street applications other uses may not be optimized if this cam design is used.
The power band is "roughly" between 1600 to 5000 RPM with 351-33 CID. Gear the vehicle accordingly.
The preferred minimum valve spring pressure is 150#-155# on the seat PAC Racing 1521, Lunati 73925, Comp 26925 or equivalent spring required. Lightweight chromemoly steel retainers and hardened valve locks required. Hardeded heavy wall push rods required for high RPM valvetrain stability. Tubular headers and free flowing muffleers and exhaust system required. Lubricants with a high zinc content recommended for long-term endurance. This camshaft core requires a steel, OEM compatible distributor gear.
Reccomended valve adjustment: Intake .000" - Exhaust .000"
Lobe lift: Intake .353" - Exhaust .353"
Gross valve lift 1.60 ratio: Intake .565" - Exhaust .565"
Duration @ .050" tappet lift: Intake 214° Exhaust 224°
Lobe seperation: 110°
Recommended Intake centerline 106°
Valve timing at .050" tappet lift: _ open ___________ close
____________________ Intake: 1° BTDC __________ 33° ABDC
__________________ Exhaust: 46° BBDC ______ -2° ATDC
Degree this camshaft, using the specs provided on this sheet. The asymmetrical design of these lobes may not allow for accurate reading using the centerline method.
This camshaft is designed for naturally aspirated high torque street applications other uses may not be optimized if this cam design is used.
The power band is "roughly" between 1600 to 5000 RPM with 351-33 CID. Gear the vehicle accordingly.
The preferred minimum valve spring pressure is 150#-155# on the seat PAC Racing 1521, Lunati 73925, Comp 26925 or equivalent spring required. Lightweight chromemoly steel retainers and hardened valve locks required. Hardeded heavy wall push rods required for high RPM valvetrain stability. Tubular headers and free flowing muffleers and exhaust system required. Lubricants with a high zinc content recommended for long-term endurance. This camshaft core requires a steel, OEM compatible distributor gear.
Old School Hot Rodder
Joined: Feb 2006
Posts: 6,472
Likes: 11
From: Exmore, VA
Ok, several items/questions first, what kind of advance curve do you have in the distributor and is it a dual (vacuum and centrifugal) or centrifugal only? I have never been a fan of MSD ignitions, anything that thinks it needs to fire multiple times doesn't trust itself.
Are you using 1.6:1 rockers, or did you go with a higher ratio? That will change the cam characteristics. Did you degree the cam as described yourself or have someone else do it?
The last 351w I built we used the Ford 351HO cam in a 4wd short bed pickup running a C6, used an Edelbrock intake probably like yours (different designations then, it was 20+ years ago) and a Holley carb, DSII ignition and headers etc. it ran like the hammers, I did the port work on a set of stock iron heads.
The erratic idle vacuum Gary describes bothers me, a torque cam shouldn't do that, good example was the old nail valve Buicks, loads of torque, had a nice idle but a very distinctive sound due to the high lift cams used.
Are you using 1.6:1 rockers, or did you go with a higher ratio? That will change the cam characteristics. Did you degree the cam as described yourself or have someone else do it?
The last 351w I built we used the Ford 351HO cam in a 4wd short bed pickup running a C6, used an Edelbrock intake probably like yours (different designations then, it was 20+ years ago) and a Holley carb, DSII ignition and headers etc. it ran like the hammers, I did the port work on a set of stock iron heads.
The erratic idle vacuum Gary describes bothers me, a torque cam shouldn't do that, good example was the old nail valve Buicks, loads of torque, had a nice idle but a very distinctive sound due to the high lift cams used.
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FTE Legend
Joined: Jul 2010
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From: Northeast, OK
Let me clarify: The needle swings probably 4" of vacuum if connected to the "manifold" port on the carb. IOW, when I said the engine runs at 15", the needle is swinging very rapidly, but very steadily, from 13" to 17" - IIRC. It isn't erratic, if erratic means that the idle isn't steady and the vacuum reading isn't steady. The engine idles well, but the cam duration is long enough to cause the vacuum to have a "pulse".
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Postmaster
Joined: Nov 2009
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From: Broken Arrow , OK
The distributor has a mechanical only advance. I dont know what the curve is ,but , I bet I can find it somewhere.
I did use 1:6 full roller rockers.
I didnt degree the cam.I installed the cam,but,just lined up the dots on the cam and crank gears like they are from the factory. Is that extremely important?
A guy named Ed Curtis(Flowtech Induction systems) from RI ground the cam using the info I supplied to him. He is supposed to be a Ford guru and is spoke of very highly on forums like the Corral(big Mustang 1/4 mile website)
. I told him I wanted 350 HP to the back wheels. I also told him my kids would be driving it so it needed to be drivable on the street.
I did use 1:6 full roller rockers.
I didnt degree the cam.I installed the cam,but,just lined up the dots on the cam and crank gears like they are from the factory. Is that extremely important?
A guy named Ed Curtis(Flowtech Induction systems) from RI ground the cam using the info I supplied to him. He is supposed to be a Ford guru and is spoke of very highly on forums like the Corral(big Mustang 1/4 mile website)
. I told him I wanted 350 HP to the back wheels. I also told him my kids would be driving it so it needed to be drivable on the street.
Old School Hot Rodder
Joined: Feb 2006
Posts: 6,472
Likes: 11
From: Exmore, VA
I hate to say it, but degreeing a performance cam can be critical to it's behavior. The advance curve in the distributor is also a key piece of the whole package. Can you try connecting the vacuum gauge to a port that gets vacuum from all 8cyls.? The "manifold" port is on on side of the carb only, try teeing into the PCV hose close to the carb.
On the cam again, keep in mind, a Bronco is a whole lot heavier than a Mustang and has a lot more rolling friction. A lot of people make the mistake of building a high performance engine for a truck and then have to turn the heck out of it. Truck street engines need low end torque, look at the specs for the Toyota Tundra 5.7L engine, they stroked the 4.7L to get it, I was amazed at the low end torque it has. My brother has either an '08 or '09 Tundra and gives me a ration about it being a "big" truck. I pointed out that my 2WD Ford is the same height as his 4WD Toy.
On the cam again, keep in mind, a Bronco is a whole lot heavier than a Mustang and has a lot more rolling friction. A lot of people make the mistake of building a high performance engine for a truck and then have to turn the heck out of it. Truck street engines need low end torque, look at the specs for the Toyota Tundra 5.7L engine, they stroked the 4.7L to get it, I was amazed at the low end torque it has. My brother has either an '08 or '09 Tundra and gives me a ration about it being a "big" truck. I pointed out that my 2WD Ford is the same height as his 4WD Toy.
Last edited by 85lebaront2; Apr 23, 2012 at 07:20 AM. Reason: Vacuum gauge added.
FTE Legend
Joined: Jul 2010
Posts: 32,875
Likes: 48
From: Northeast, OK
I hate to say it, but degreeing a performance cam can be critical to it's behavior. The advance curve in the distributor is also a key piece of the whole package. Can you try connecting the vacuum gauge to a port that gets vacuum from all 8cyls.? The "manifold" port is on on side of the carb only, try teeing into the PCV hose close to the carb.
On the cam again, keep in mind, a Bronco is a whole lot heavier than a Mustang and has a lot more rolling friction. A lot of people make the mistake of building a high performance engine for a truck and then have to turn the heck out of it. Truck street engines need low end torque, look at the specs for the Toyota Tundra 5.7L engine, they stroked the 4.7L to get it, I was amazed at the low end torque it has. My brother has either an '08 or '09 Tundra and gives me a ration about it being a "big" truck. I pointed out that my 2WD Ford is the same height as his 4WD Toy.
On the cam again, keep in mind, a Bronco is a whole lot heavier than a Mustang and has a lot more rolling friction. A lot of people make the mistake of building a high performance engine for a truck and then have to turn the heck out of it. Truck street engines need low end torque, look at the specs for the Toyota Tundra 5.7L engine, they stroked the 4.7L to get it, I was amazed at the low end torque it has. My brother has either an '08 or '09 Tundra and gives me a ration about it being a "big" truck. I pointed out that my 2WD Ford is the same height as his 4WD Toy.
Bruno, I have a degree wheel and a dial indicator with magnetic base. It would be a bit of work, but you could pull the harmonic balancer and a valve cover and determine where the cam is sitting by checking the .050" lift points. And, that would be a good time to put a timing indicator on since you'll be "right there". We'd want to start some morning to give us all day as that would also be the time to change the cam timing if it is off, and obviously that requires pulling the timing cover. But, even if it isn't off at least you'd have a warm fuzzy that it is right.
FTE Legend
Joined: Jul 2010
Posts: 32,875
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From: Northeast, OK
Well, he says he has one - on the drivers side. Under the PS pump and rad hose. Can't be seen from top to time it. Plans to put one on passenger side.