1 5/8 or 1 3/4 Full Tube Headers... Help decide...

[Piston]

Lets see I'm confused as to what to do with my current exhaust system. My new motor is about to be dropped in and I'm wondering if the 1 5/8 Hooker Full Tubes headers are big enough. I'm putting in a 331 stroker with 10.5 compression and a n-91 cam which is something of the like .600 lift (w/ 1.7 rockers) and 280/280 duration. The cam is a Hi-Rev cam and it wants to see 6900rpm. However, I will be shifting at around 6700 since I want longetiviy out of this block. Resting on top of the short block are tfs Stage II ported heads (w/ new valves, and titanium retainers) which flow ~280cfm at that lift. I will have a Holley Systemax intake(haven't decided between that or the RPMII) and 80MAF with 30lb injectors along with 75mm TB. With this higher reving application I'm worried about my exhaust setup not being enough. However, I do not want to blow $800 dollars on new headers and 3 inch pipe all the way back if it's not going to do much for me. So I turn here hoping someone has been in this scenerio before. I'm hoping to achieve 500hp N/A at the flywheel. I have been told by numerous sources that this combination should get me really close. I'm just curious to know if the 1 3/4 headers will hurt performance or if the motor warrants the extra flow.

 

[1BAD351]

Well it would seem that your longtubes will be too restrictive. I would suggest welding Folger's coffee cans together all the way out the back. This shouldn't cost too much either, you can pick up 30 cans of Folgers for about $100. Full exhaust for about $100........count me in.

 

[Piston]

I must have posted to ricer forum for a response like that.

 

[95GTvert[bv12]]

if you are hoping to get 500na you might want to go with the bigger 1 3/4 in becuase your going to have to spin the motor to 7500 and your going to want all the flow your can get in the exhaust.

:edit:
sorry said 1 1/2 ment 1 3/4

 

[Joes95GT]

1 5/8" will do in a pinch. 1 3/4" would be better.

Joe

 

[Piston]

if you are hoping to get 500na you might want to go with the bigger 1 3/4 in becuase your going to have to spin the motor to 7500 and your going to want all the flow your can get in the exhaust.

Ouch, 7500RPM who spins their 2bolt main block that high? How long will that last? It's not a b50 sportsman block which I wish it was but it's too damn expensive.

As far as 1 3/4 full tubes any recommendations on brand? I need them to clear a lakewood saftey bellhousing and a 7qt oil pan (it's the type for lowered stangs, where it's more wide then the usual). What kinda difference in TQ & HP are we talking about here, anyhow?

 

[Joes95GT]

Ouch, 7500RPM who spins their 2bolt main block that high? How long will that last? It's not a b50 sportsman block which I wish it was but it's too damn expensive.

As far as 1 3/4 full tubes any recommendations on brand? I need them to clear a lakewood saftey bellhousing and a 7qt oil pan (it's the type for lowered stangs, where it's more wide then the usual). What kinda difference in TQ & HP are we talking about here, anyhow?

500 engine horsepower is extremely do-able with a peak power point of 6900 RPM, assuming you have all the right top end pieces. I would recommend Kooks or Hooker for the headers. They are very expensive, but they will custom make them to fit around everything that you need them to fit around.

Joe

 

[Piston]

500 engine horsepower is extremely do-able with a peak power point of 6900 RPM, assuming you have all the right top end pieces. I would recommend Kooks or Hooker for the headers. They are very expensive, but they will custom make them to fit around everything that you need them to fit around.

That's the goal here 500 N/A ponies. As long as I break 400RWHP I think I will have to walk away happy but would like to see about ~430RWHP after a good tune.

I currently do run the Hookers and do like them. I will try to find a pair of 1 3/4 hookers and hope they fit. Never heard of Kooks though. What kind of setup do you have after the headers? X or H pipe? Does the size of the H or X pipe matter? If yes what is recommended? Will I have to redo my whole exhaust to accomdate the 1 3/4 headers? I'm thinking 3inch pipe all the way out back that sound good or is that too much?

 

[Joes95GT]

I'm thinking 3inch pipe all the way out back that sound good or is that too much?

Nope, that's what you should use. Yes, it would be best for you to redo your whole exhaust to accomodate the bigger motor. I know MAC makes H-pipes in 3" size. The H or X doesn't really make a difference performance wise. I personally would go with an H-pipe just for the sound (personal preference).

Joe

 

[Piston]

Thanks Joe. I will consider a exhaust upgrade after I get my car dynoed as recommened by Dallas Mustang. I called DM for price on 1 3/4 headers and they are claiming that my motor will not make the 500hp that I'm trying to achieve. With that in mind they said 1 3/4 exhaust is too big. However, I'm trying to build a 500flywheel hp motor here and I thought I had the right parts for the job. However, Dallas Mustangs didn't ask me anything other then my Cubic Inches (331) and they discredited it right away. Makes me wonder. Basicaly they told me if I make more the 460HP then go with the 1 3/4 inch Headers and 3 inch pipe otherwise I will lose HP.

 

[Joes95GT]

Thanks Joe. I will consider a exhaust upgrade after I get my car dynoed as recommened by Dallas Mustang. I called DM for price on 1 3/4 headers and they are claiming that my motor will not make the 500hp that I'm trying to achieve. With that in mind they said 1 3/4 exhaust is too big. However, I'm trying to build a 500flywheel hp motor here and I thought I had the right parts for the job. However, Dallas Mustangs didn't ask me anything other then my Cubic Inches (331) and they discredited it right away. Makes me wonder. Basicaly they told me if I make more the 460HP then go with the 1 3/4 inch Headers and 3 inch pipe otherwise I will lose HP.

What kind of heads are on the car? Those Anderson cams have an awesome reputation of putting down some serious horsepower and as long as you have a decent head on the car with an intake that will flow with the heads, the motor should make 500 horsepower. I would disregard what that idiot at DM said. If he didn't even ask how high you are going to spin the motor, or what kind of head is on the car, who is he to tell you what the motor can/can't do.

Joe

 

[Piston]

Heh, glad you said that cause that dude had me putting down a few too many Heinkens last night while working on the car with some buddies. Actually it was a good excuse to drink.

I have TFS Stage II anderson ported heads (w/ new springs, and titanium retainers) which flow ~280cfm at that lift. I will have a Holley Systemax intake(haven't decided between that or the RPMII) and 80MAF with 30lb injectors along with 75mm TB (75 to big?). I might be tempted to go with the RPMII if the lower of my existing ported Performer would work.

 

[Joes95GT]

Heh, glad you said that cause that dude had me putting down a few too many Heinkens last night while working on the car with some buddies. Actually it was a good excuse to drink.

I have TFS Stage II anderson ported heads (w/ new springs, and titanium retainers) which flow ~280cfm at that lift. I will have a Holley Systemax intake(haven't decided between that or the RPMII) and 80MAF with 30lb injectors along with 75mm TB (75 to big?). I might be tempted to go with the RPMII if the lower of my existing ported Performer would work.

The Performer lower will work with the RPM II. Either manifold would be an excellent choice. Go with the 75mm TB. As long as the cam is set up right for the heads (right lift and duration), which I'm sure it is if they are both Anderson products, then 500 FWHP should be no problem.

Joe

 

[Piston]

Ok, Thanks Joe.