351 deck hight is different... Long tube headers wont fit. And ussually unless you special order them, there primaries are way to small anyways. You will create turbulence right out of the port...

As far as the pipe??? Around here, you would get laughed at with that analagy. Smaller is never better. He is running an muffler anyways if your worried about back preassure. When I race my car? open headers. When I run my street car, I pull the lever, and open exhaust. My SUperDuty doesnt even have 2.5 stock.

An engine is basically an Aircompressor. Air in, Air out. More in, More out... So on and so forth...

As far as the budget, set your exhaust up, and then hit a few swap meets, you should be able to get a set of headers more affordabley

 

On a drag car that runs about 4000-7500 rpm & is set up to run open headers is the way to go . On a street / strip car that runs about 2500-6000 its better to just run a free flowing exhaust , running open headers in most cases will just slow the car down , thats from my personal experience . And 302 & 351 heads are all interchangable , i run 351 heads on a 302 , and 302 headers bolt to the heads & work just fine....Lew

 

302 headers will not fit on a 351 properly I dont know what the hell your talkin about ... Ya they may bolt up. thats about it. I have always laughed when people are told they work. The ports arent correct... The deck hight is the factor. I guess one would wonder. WHy buy 302 headers, and put them on a 351, when you can just buy 351 headers???

As far as cars at the track... This guy is putting them in a truck.

 

It's obvious you haven't seen a stock windsor engine in some time.. both motors use the exact same heads so 302 headers will fit a 351 motor no problem. But since the 351 is taller and wider 302 headers will create some frame clearance problems in a truck so it's still a good idea to get engine specific headers. The primary tube size is not an issue however.

Hey I don't mind getting laughed at.. there's lots of people out there that really don't know as much as they think they know. It's not about creating backpressure.. an engine doesn't need backpressure, it's just that most people WAY over estimate the airflow capacity of these motors. In stock form they really don't move more than about 400cfm of air so there's really no need for anything bigger than a 2.5" single with high flow components. I mean the motor will run just fine with dual 3" pipes on it.. it's EFI so as long as the O2 sensor is installed it'll be OK, but it's far from optimal to produce effective cylinder scavenging at low rpm, so the motor won't be a torquy as it could be. Ya see I'm not talking about putting a tiny little pipe on the motor so it sounds like an air compressor, I'm just suggesting something that's scaled more appropriately for the actual motor under the hood.

 

...You need to read the post , where did i say put 302 headers on a 351 ??? I said i have a 302 with 351 heads with 302 headers because its a 302 ...GET IT ???? Don't you know they will enterchange ... Any one that works on mustangs knows this , its very comon . So you just don't know much about stangs & our trucks....Lew

 

Well I guess I fold my deck on this one... Like the old saying Never fight with ingnorance, because people might forget who the ignorant ones are.


I will add incloseing No one ever argued the heads them selvs were different, but the deck hight is most definately. As I stated, they will bolt up, thats about it.

I watch some posts of your Conanski, and wonder. if they are malicious or are you really that far off. One in the know would wonder.

 

Good , at least you know how to play poker...

 

Well no I hope I don't come across as malicious that not my intention.. maybe I use too much strong language sometimes. It's just that I have done quite a bit of wrenching and experimenting on these 5.0 and 5.8 EFI motors over my 40+ laps around the sun and have proven to myself numerous times that the stuff that works on a drag car is ALL WRONG for a street driven truck. I know some people have a hard time accepting ideas that go against the grain, very few people here believe the 5.0HO intake would produce better results on a stock truck motor than the truck intake for example, nobody wants to believe that the Ford engineers could have a made a mistake. But there's lots of evidence that this is true starting with the factory output specs for both motors, the HO makes more TQ.. everywhere. If bigger were always better then this simply wouldn't happen because the truck intake is roughly twice the volume of the car intake, but size is just one part of the formula with a tuned runner intake just like it is with a tuned exhaust system. Again with EFI it'll still work if there is a gross mismatch but it just won't deliver optimum results, and that is what I always target.

 

Well... As a drag racer... a 4 time winner at bowling green truck pulls. Street rodder, work on a pit crew for a couple front engine dragsters, and on any given day of the week, a driveway wrencher for many people lookin for power in everything including motor homes.

I can debated this, but I also learned it doesnt matter. We all have opinions I guess, and as I have said many times Thats what makes the world go around. and thats what keeps friends and friends asking me for my input.

Simply put; An internal combustion engine, is essentialy an Air pump. More in, more out. There are factors. Compression ratio for one. I have always pushed the limits, and it comes with a price. I tuned a friend of a friends engine. He had 2 1/2 inch exhaust. I told him what I would reccomend, he basically gave me a blank check, (his engine wasnt making the HP he was told it would) I worked the intake, carb, ignition, and exhaust. I also warned him that if the bottom end wasnt what he said it was, dont hold be responsible. I will tell you, the car scared him, and on his second pass, his bottom end of the block cracked in half right under the freeze plugs. Crank pan rods pistons broke his rack in 2. I will have pictures, and post them for you... PS he wants me to build him a 351 now. I warned him of the weak 302 block. Simply put, I can make HP but not with a 2 1/2 inch exhaust, or small intake runners.

 

Mustang6147, by any chance are you on sbftech.com?

 

No... why??

 

Well see that's exactly why we disagree here, I'm not talking about making the most peak HP from a motor, I'm talking about making maximum TQ across the stock powerband.. idle - 4500rpm. There's only so much HP you can get out of the stock components on these EFI truck motors anyway so unless somebody is prepared to pony up big $$ and build a motor from scratch it ain't gonna happen, and you gave a great example of why this is. If they did then yeah.. the exhaust would have to be a lot bigger, but usually we're talking about guys that just want a little more power than stock around here, so the exhaust really only needs to flow a little better than stock.

 

Cause there you can find real tech, unlike here where bs tech is everywhere. The people on there are actually established racers and engine builders.

From the skimming ive read in this thread, your posts are correct.

 

Man I think this is my most popular thread yet! Got the exhaust Jerry rigged enough together so I can drive it and still hear my self think, still need to pick up 2 2.5'' pipe clamps though, and a few other little things, you guys are going to have too see this set up to believe it, ill post pics in the afternoon. Well I took her for her maiden voyage down to Carls Jr to grab me a burger. Never took it over 2500 while trying to vary RPM as much as I could with out making too much noise. Only pushed her to 3000 once to see how it pulled, it was very snappy, even with the ****ty exhaust. I'm happy, idles butter smooth, even with out the PVC hooked up yet. As soon as California gets their head out of their *** I should be able to get a better flowing exhaust, because I am stuck with the stock cats.

 

Thanks, Honestly... I scratch my head sometimes also... I am going to check out that forums to.