347 carb question 65 mustang
03-23-2011, 12:15 PM
#11
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Where are all these unhappy people (who didn't use the assembled parts)?? In general, I hate Chinese junk more than most, but very few who actually OWN the heads are griping. It's always someone passing on info. The complaints seem to be in cheap assembly parts which don't apply here. Got any firsthand info to share?
As far as exhaust goes, I absolutely hate headers. If the manifolds feel like they are holding me back then I will obviously reconsider, but I had headers on here before and they were a pain.
03-23-2011, 12:18 PM
#12
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sounds like your going about your build the wrong way.No headers and you want a powerband from 3000-6000 to avoid tire spin? Do you understnd what kind of intake and cam makes power int that range?
Nothing wrong with Pro Comp heads as long as they are not used out of the box.I have them on mine, but they are totally reworked and CNC'd.
Nothing wrong with Pro Comp heads as long as they are not used out of the box.I have them on mine, but they are totally reworked and CNC'd.
03-23-2011, 12:34 PM
#14
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03-23-2011, 12:47 PM
#15
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Just look at the powerband of the parts.For example a Performer RPM manifold is 1500-6000. A single plane Victor jr is 3500-7000 i think. The cam you mentioned a 268 is a little above stock which has a low end torque powerband.Again a bigger cam would put you in the 3000+ rpm range, but your idle would be more drastic and you would need more compression probably.Then your gears will not work for that cam.So its a domino effect.Your engine builder should be able to suggest what you need based on what he builds.
03-23-2011, 01:27 PM
#16
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Hipo manifolds might as well be a cork on a built up 347. Seriously, those things will probably cost you 40-50hp at least.
For a cam, just get a custom grind. You'll have power where you want it, with drivability, idle etc. Money well spent. Though on a 347 you're going to have wheel spin on street tires, period.
As for the heads, the problem isn't who assembles them. The problem is the Pro Comp heads are low quality control castings from China. It's quite common for them to develop leaks through port walls, cracks etc. Some people are lucky and get a set that are fine, some people get them and end up with a car that won't even run.
And just FYI, if you're going to ignore us and go with the hipo manifolds, then save your money on a 347 kit. A 347 with hipo manifolds, a weak cam and crappy heads won't make any more power than a 302 with the same parts. No sense in getting a stroker kit if you're not going to benefit from it.
For a cam, just get a custom grind. You'll have power where you want it, with drivability, idle etc. Money well spent. Though on a 347 you're going to have wheel spin on street tires, period.
As for the heads, the problem isn't who assembles them. The problem is the Pro Comp heads are low quality control castings from China. It's quite common for them to develop leaks through port walls, cracks etc. Some people are lucky and get a set that are fine, some people get them and end up with a car that won't even run.
And just FYI, if you're going to ignore us and go with the hipo manifolds, then save your money on a 347 kit. A 347 with hipo manifolds, a weak cam and crappy heads won't make any more power than a 302 with the same parts. No sense in getting a stroker kit if you're not going to benefit from it.
My thinking is that I want to go 347 to compensate for the high gear ratio 3.00. I don't want a lower gear.
Guys, this is not a drag car okay...I am building a street/highway racer that I am hoping will hang with a newer GT.
03-23-2011, 01:37 PM
#17
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Just look at the powerband of the parts.For example a Performer RPM manifold is 1500-6000. A single plane Victor jr is 3500-7000 i think. The cam you mentioned a 268 is a little above stock which has a low end torque powerband.Again a bigger cam would put you in the 3000+ rpm range, but your idle would be more drastic and you would need more compression probably.Then your gears will not work for that cam.So its a domino effect.Your engine builder should be able to suggest what you need based on what he builds.
http://www.youtube.com/watch?v=F7Y6IRyNGuM
03-23-2011, 01:51 PM
#18
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So you want to hang with a new GT? Not gonna happen with your limitations your puttin on it. You want want top end speed, but are you giving any thought to brakes or suspension? A 4 speed will limit you in bottom end because you dont want a deeper gear.
I dont see this as being a serious build, sorry.
03-23-2011, 01:54 PM
#19
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Im sorry, i dont see anything in that video that stands out as being "built"
So you want to hang with a new GT? Not gonna happen with your limitations your puttin on it. You want want top end speed, but are you giving any thought to brakes or suspension? A 4 speed will limit you in bottom end because you dont want a deeper gear.
I dont see this as being a serious build, sorry.
So you want to hang with a new GT? Not gonna happen with your limitations your puttin on it. You want want top end speed, but are you giving any thought to brakes or suspension? A 4 speed will limit you in bottom end because you dont want a deeper gear.
I dont see this as being a serious build, sorry.
03-23-2011, 02:50 PM
#20
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Not if it's built wrong.
First, if you get a custom cam it'll be set up for the parts you use, including exhaust. A cam ground for hipo manifolds will have a way different profile than one ground for headers. It's going to have to try an compensate for a ridiculously restrictive exhaust system and prolly end up with tons of exhaust duration. Then if you put headers on later, you're going to have way to much exhaust on your cam.
Second, the hipo manifolds are going to be so restrictive, you're not going to benefit much from the heads, cam etc. If you can't get exhaust out of the cylinder, you can't get fresh air/fuel charge in. Those manifolds are fine on a 289/302 with stock or modified stock heads and a small cam, but will absolutely destroy the power potential on a built 302 and especially a 347. Efficiency will drop like a rock, you'll have exhaust contaminated fuel/air charge in the cylinder, and the power will be crap, it will get bad mileage, and may even run hot or detonate.
As far as headers not fitting right, you can't buy cheap headers and expect quality. Flange warpage and leaks are a result of inferior quality headers. You pay $130 for headers, you get $130 headers. You pay $600 for headers, you get $600 headers. Some brands fit better, some brands are better quality, some are stupid expensive and not even that great, but for the most part, you get what you pay for. The Doug's I have in mine went in once, got tightened once at installation, and that was it....no leaks, no warpage(their flanges are huge), no problems.
And as for traction control, it's called keep your foot off the throttle. You are not going to build an engine that controls tire spin at lower rpm without building an engine that's really inefficient at low rpm....which means poor performance and poor mileage. It will drive like crap and suck tons of fuel. My 302 has a custom cam ground for 3,000-6,500rpm best torque, with good response and power in the 2k rpm range.....even not being tuned right yet, it still rapes tires under 3k rpm. And it's a 302, not a 347.
As far as the Pro Comp heads, when they came out there were tons of threads all over this forum, mainly in the 5.0 section(and other forums) about complete horror stories. People with first hand experience and photos of intake port walls so thin they broke through into pushrod holes, guide failures etc. Think about it, how do you think Pro Comp can sell a head for half the price of their competitor without using low quality materials etc? The newer ones may be better, but the general consensus is spend the money to get a better head. If you want to run one that's up to you, but it is a bit of a gamble. That and the Pro Comp heads aren't as well developed, and virtually every other "smaller" head like the smaller port AFR, Edelbrock, TFS etc heads always outperform them.
Just be aware, if you build the 347 you're talking about the way you stated, it's going to perform like crap, get bad mileage, and you'll be getting raped by 302's all the time. You'll end up wasting a ton of money.
If you stick those heads on a 302(make sure their thoroughly inspected before being assembled with good parts, don't use any of their valves, guides etc) with a good custom hyd roller cam, and a decent exhaust(basic quality headers, x pipe etc), you'll spend the same amount of money(maybe even less) and have an engine that performs WAY better than a 347 with the same heads, hipo manifolds and a small cam.
traction is ALWAYS going to be a problem on well built engines. Modern engine technology can make tons of power from off idle to over 6k rpm quite easily. Run huge tires and/or learn to control your right foot.
First, if you get a custom cam it'll be set up for the parts you use, including exhaust. A cam ground for hipo manifolds will have a way different profile than one ground for headers. It's going to have to try an compensate for a ridiculously restrictive exhaust system and prolly end up with tons of exhaust duration. Then if you put headers on later, you're going to have way to much exhaust on your cam.
Second, the hipo manifolds are going to be so restrictive, you're not going to benefit much from the heads, cam etc. If you can't get exhaust out of the cylinder, you can't get fresh air/fuel charge in. Those manifolds are fine on a 289/302 with stock or modified stock heads and a small cam, but will absolutely destroy the power potential on a built 302 and especially a 347. Efficiency will drop like a rock, you'll have exhaust contaminated fuel/air charge in the cylinder, and the power will be crap, it will get bad mileage, and may even run hot or detonate.
As far as headers not fitting right, you can't buy cheap headers and expect quality. Flange warpage and leaks are a result of inferior quality headers. You pay $130 for headers, you get $130 headers. You pay $600 for headers, you get $600 headers. Some brands fit better, some brands are better quality, some are stupid expensive and not even that great, but for the most part, you get what you pay for. The Doug's I have in mine went in once, got tightened once at installation, and that was it....no leaks, no warpage(their flanges are huge), no problems.
And as for traction control, it's called keep your foot off the throttle. You are not going to build an engine that controls tire spin at lower rpm without building an engine that's really inefficient at low rpm....which means poor performance and poor mileage. It will drive like crap and suck tons of fuel. My 302 has a custom cam ground for 3,000-6,500rpm best torque, with good response and power in the 2k rpm range.....even not being tuned right yet, it still rapes tires under 3k rpm. And it's a 302, not a 347.
As far as the Pro Comp heads, when they came out there were tons of threads all over this forum, mainly in the 5.0 section(and other forums) about complete horror stories. People with first hand experience and photos of intake port walls so thin they broke through into pushrod holes, guide failures etc. Think about it, how do you think Pro Comp can sell a head for half the price of their competitor without using low quality materials etc? The newer ones may be better, but the general consensus is spend the money to get a better head. If you want to run one that's up to you, but it is a bit of a gamble. That and the Pro Comp heads aren't as well developed, and virtually every other "smaller" head like the smaller port AFR, Edelbrock, TFS etc heads always outperform them.
Just be aware, if you build the 347 you're talking about the way you stated, it's going to perform like crap, get bad mileage, and you'll be getting raped by 302's all the time. You'll end up wasting a ton of money.
If you stick those heads on a 302(make sure their thoroughly inspected before being assembled with good parts, don't use any of their valves, guides etc) with a good custom hyd roller cam, and a decent exhaust(basic quality headers, x pipe etc), you'll spend the same amount of money(maybe even less) and have an engine that performs WAY better than a 347 with the same heads, hipo manifolds and a small cam.
traction is ALWAYS going to be a problem on well built engines. Modern engine technology can make tons of power from off idle to over 6k rpm quite easily. Run huge tires and/or learn to control your right foot.