347 vs 351. Patience/Assistance Requested.
08-16-2009, 10:49 PM
#1
1st Gear Member
Thread Starter
Join Date: May 2009
Location: Utah
Posts: 90
347 vs 351. Patience/Assistance Requested.
My oh my. I have seen many debates over a plethora of forums and websites about this.
My question is:
Where am I going to get the best performance?
I've heard that a properly built 347 will stomp on 351's consistently, but I've heard that I can also attain almost identical results with a practically stock 351.
Let me start by explaining where I'm at, what my goals are, the limitations of my budget, and where I hope to be within the next year(Goals).
I recently bought a 1988 Mustang GT - HO.
It was only drivable for the first 4 days, as one night a Lifter began to stick. There were multiple attempts at fixing it without going the full-rebuild route, but in the end that decision was made. Upon further investigation my buddy and I discovered the Oil Pump had siezed and the Oil Pump Drive Shaft had twisted and broken off at the bottom of the distributor(I still have the Shaft. Saving it as a souvenir). I spent about $1300, re-using the old pistons(after cleaning them up, etc), having the heads re-worked, all new gaskets, timing chain and gears, rings, etc etc. The whole shebang.
Since then she is running well. After driving for a little while it is somewhat of a pain to get it into First gear(I am thinking I need to re-adjust the clutch cable, as I have to nearly push the clutch pedal all the way to the ground to get it to engage). There is a small leak from an unknown source(Thinking possibly Power-Steering, as it is whining regardless of fluid being added, or possibly a very small oil leak). There are also 2 wires of an unknown origin hanging down on the ground near where the block connects to the transmission. The suspension is shot, and according to the fellow at Les Schwab, a bushing/nut has freed itself up, causing a pinging sound. The previous owner had cut the springs, so it's a horrible ride nonetheless, and the suspension was one of my first projects(Going with a 1.4i drop in the front, 1.7i in the back).
The exhaust is cut off after the mufflers, but thankfully I live in a County where emissions is not required, but they will be fixed regardless.
The Alternator is going out and needs to be replaced quickly. It also idles fairly high(or at least I believe so, 1300ish at times)
I also had a problem the other night with after taking a long trip(30 or so miles) and almost arriving at my home, she would attempt to cut out/die whenever I gave her some gas or attempted to release the clutch. After reading up on these forums, I've come to the conclusion that it may be the fuel pump, but it has only happened on one occasion so I am still up for suggestions.
That is where I am at. Where would I like to be?
I've always wanted a 5.0 Mustang. Strangely enough I wasn't able to get a loan for $1500 for one I wanted back in the day, but I was able to go to a car dealership and obtain a 2006 Ford Focus ZX3. I had many dreams and aspirations for that car, and she was quick as-she-was, but after an incident I ended up having her repossessed. About a year later, by luck, I was able to obtain my Mustang, and I love it.
I have planned on going the 347 Stroker Route for quite a while after reading a bunch on these forums, but I am still sketchy. I'm looking for a great setup, and eventually plan on Twin-Turbo-ing it via STS Performance.
My budget as of now is..well, nothing. I am currently looking for employment with the help of a program that will sponsor me for an internship, rated at 8.00 an hour regardless of where I go, which comes out to $1280.00 a month, no taxes taken out.
I'm sure there's more, but I am positive I have taken up enough of your time and if you've actually had the patient to sit back and read all of this, I applaud you.
Any help is greatly appreciated. If any other information is needed, please inform me and it will promptly be provided.
My question is:
Where am I going to get the best performance?
I've heard that a properly built 347 will stomp on 351's consistently, but I've heard that I can also attain almost identical results with a practically stock 351.
Let me start by explaining where I'm at, what my goals are, the limitations of my budget, and where I hope to be within the next year(Goals).
I recently bought a 1988 Mustang GT - HO.
It was only drivable for the first 4 days, as one night a Lifter began to stick. There were multiple attempts at fixing it without going the full-rebuild route, but in the end that decision was made. Upon further investigation my buddy and I discovered the Oil Pump had siezed and the Oil Pump Drive Shaft had twisted and broken off at the bottom of the distributor(I still have the Shaft. Saving it as a souvenir). I spent about $1300, re-using the old pistons(after cleaning them up, etc), having the heads re-worked, all new gaskets, timing chain and gears, rings, etc etc. The whole shebang.
Since then she is running well. After driving for a little while it is somewhat of a pain to get it into First gear(I am thinking I need to re-adjust the clutch cable, as I have to nearly push the clutch pedal all the way to the ground to get it to engage). There is a small leak from an unknown source(Thinking possibly Power-Steering, as it is whining regardless of fluid being added, or possibly a very small oil leak). There are also 2 wires of an unknown origin hanging down on the ground near where the block connects to the transmission. The suspension is shot, and according to the fellow at Les Schwab, a bushing/nut has freed itself up, causing a pinging sound. The previous owner had cut the springs, so it's a horrible ride nonetheless, and the suspension was one of my first projects(Going with a 1.4i drop in the front, 1.7i in the back).
The exhaust is cut off after the mufflers, but thankfully I live in a County where emissions is not required, but they will be fixed regardless.
The Alternator is going out and needs to be replaced quickly. It also idles fairly high(or at least I believe so, 1300ish at times)
I also had a problem the other night with after taking a long trip(30 or so miles) and almost arriving at my home, she would attempt to cut out/die whenever I gave her some gas or attempted to release the clutch. After reading up on these forums, I've come to the conclusion that it may be the fuel pump, but it has only happened on one occasion so I am still up for suggestions.
That is where I am at. Where would I like to be?
I've always wanted a 5.0 Mustang. Strangely enough I wasn't able to get a loan for $1500 for one I wanted back in the day, but I was able to go to a car dealership and obtain a 2006 Ford Focus ZX3. I had many dreams and aspirations for that car, and she was quick as-she-was, but after an incident I ended up having her repossessed. About a year later, by luck, I was able to obtain my Mustang, and I love it.
I have planned on going the 347 Stroker Route for quite a while after reading a bunch on these forums, but I am still sketchy. I'm looking for a great setup, and eventually plan on Twin-Turbo-ing it via STS Performance.
My budget as of now is..well, nothing. I am currently looking for employment with the help of a program that will sponsor me for an internship, rated at 8.00 an hour regardless of where I go, which comes out to $1280.00 a month, no taxes taken out.
I'm sure there's more, but I am positive I have taken up enough of your time and if you've actually had the patient to sit back and read all of this, I applaud you.
Any help is greatly appreciated. If any other information is needed, please inform me and it will promptly be provided.
Last edited by Mattalicious; 08-16-2009 at 11:33 PM.
08-17-2009, 07:25 AM
#2
5th Gear Member
Join Date: May 2007
Location: Pittsburgh
Posts: 2,459
Take care of the problems you have now, and you will be very satisfied at where the car will be, before doing major mods.
The high idle could be a result of vacuum leaks, check every vacuum line and make sure none of them are cracked(20 year old hard plastic lines are very brittle). You could possibly have a vac leak under the dash board at the HVAC, although it is uncommon. To test for this just cap the vac line on the vacuum tree labeled A/C, if it fixes the problem then great, if not reconnect the A/C vac line.
Definitely adjust your clutch, that's probably your reason for having trouble getting into first gear. I wouldn't drive my car, or anyone else's, without a properly adjusted clutch.
What suspension nut/bushing has free'd itself up? The only nut that holds a bushing on is the sway bars/shocks/stuts. Fix this immediately, as it is a cheap fix and a major performance issue.
That doesn't sound like your fuel pump. When mine pooped on me it would stop working due to overheating, there would be no fuel pressure or fuel and the car would die. Upon cooling down (10+ minutes) it would run again no problem until it overheated again.
Take pics of the wires hanging between the trans and block. Loose wires are never good. If one of them is a power wire make sure it's not touching the block/body so you don't have a parastic drain or short.
As for 347 vs. 351. A 347 is a maxed out 302... a 351 is a ....unmolested 351. There's always room to grow on a 351, displacement wise. With "equal" mods a 347 will perform almost the same as a 351 due to the displacement being basically the same.
For a street car, twin turbos on even a 302 would be adequate if built right. A stroked out 351 would produce alot more power, but on the street what are you going to do with it? Smoke off sets of tires and never get traction...
The high idle could be a result of vacuum leaks, check every vacuum line and make sure none of them are cracked(20 year old hard plastic lines are very brittle). You could possibly have a vac leak under the dash board at the HVAC, although it is uncommon. To test for this just cap the vac line on the vacuum tree labeled A/C, if it fixes the problem then great, if not reconnect the A/C vac line.
Definitely adjust your clutch, that's probably your reason for having trouble getting into first gear. I wouldn't drive my car, or anyone else's, without a properly adjusted clutch.
What suspension nut/bushing has free'd itself up? The only nut that holds a bushing on is the sway bars/shocks/stuts. Fix this immediately, as it is a cheap fix and a major performance issue.
That doesn't sound like your fuel pump. When mine pooped on me it would stop working due to overheating, there would be no fuel pressure or fuel and the car would die. Upon cooling down (10+ minutes) it would run again no problem until it overheated again.
Take pics of the wires hanging between the trans and block. Loose wires are never good. If one of them is a power wire make sure it's not touching the block/body so you don't have a parastic drain or short.
As for 347 vs. 351. A 347 is a maxed out 302... a 351 is a ....unmolested 351. There's always room to grow on a 351, displacement wise. With "equal" mods a 347 will perform almost the same as a 351 due to the displacement being basically the same.
For a street car, twin turbos on even a 302 would be adequate if built right. A stroked out 351 would produce alot more power, but on the street what are you going to do with it? Smoke off sets of tires and never get traction...
08-17-2009, 07:46 AM
#5
D.R. THE PATHETIC DORK
Join Date: Jun 2007
Location: West Virginia
Posts: 30,863
08-17-2009, 01:11 PM
#6
1st Gear Member
Thread Starter
Join Date: May 2009
Location: Utah
Posts: 90
Thanks for the input. I may have worded a few things wrong in my original post.
As for the 347/351 question, a friend of mine suggested going the 347 route, and eventually buying a 351 and building it from the ground up over time, then having a replacement engine in case anything happens.
I figured I'd re-do all of the electrical/vacuum lines off the bat, although electrical is not my forte. There is a shop near my house called The Mustang Ranch where they do restorations of classic Mustangs and they said they could completely re-do all of the wiring/vacuum lines for $300-$400. Is that a fair price?
As for those wires hanging down, I will take a picture, and immediately get on fixing the current problems.
Thanks. =]
As for the 347/351 question, a friend of mine suggested going the 347 route, and eventually buying a 351 and building it from the ground up over time, then having a replacement engine in case anything happens.
I figured I'd re-do all of the electrical/vacuum lines off the bat, although electrical is not my forte. There is a shop near my house called The Mustang Ranch where they do restorations of classic Mustangs and they said they could completely re-do all of the wiring/vacuum lines for $300-$400. Is that a fair price?
As for those wires hanging down, I will take a picture, and immediately get on fixing the current problems.
Thanks. =]
08-17-2009, 01:15 PM
#7
6th Gear Member
Join Date: Apr 2007
Location: California
Posts: 10,468
Bore and stroke are basically the same, most of the parts are pretty much the same, but the 347 is a lighter package with lighter internal components, plus the shorter deck height means shorter pushrods, and better valvetrain stability. 347>351. If you build off a 351 then build a 408.
08-17-2009, 01:53 PM
#8
D.R. THE PATHETIC DORK
Join Date: Jun 2007
Location: West Virginia
Posts: 30,863
08-17-2009, 02:05 PM
#10
1st Gear Member
Thread Starter
Join Date: May 2009
Location: Utah
Posts: 90
depends on what redo all the wiring means?? doubt they are gonna replace the harness and as for the vaccum lines, once again depends what they consider redo means........personally I'd fix what needs to be fixed and not just throw parts at it and hope that cures whatever your issues are