#1  
Old 06-09-2022, 11:17 AM
er455 er455 is offline
Senior Chief
 
Join Date: Mar 2011
Posts: 416
Default D ports vs round port heads

Ok what are the HP limits with D port aluminum heads vs round ports in a turbo application ?

  #2  
Old 06-11-2022, 12:15 PM
JLMounce JLMounce is online now
Ultimate Warrior
 
Join Date: Sep 2005
Location: Greeley, Colorado
Posts: 3,679
Send a message via AIM to JLMounce
Default

Street application? Probably minimal. I believe I've read before you run something like an s480, is that correct?

That thing will probably make every bit of 1100 hp...to the tire, at about 15 psi on an aftermarket headed 455, regardless of what head is on it. In fact, I'd bet it would do it on a set of as cast D or round ports if you push the boost up a bit.

I'd be more worried about a factory block holding together than I would be concerned about which port type I'd be using.

That being the case, something like an SD 290cfm KRE D port with a properly sized cam in a normally aspirated 460" Pontiac will typically ring the bell between 550-570hp. With something like an s480 pumping an additional 14.7psi into it, you're in 4 digit hp territory. Knowing you already have D ports which your hot side is designed around, I'd do either the Edelbrock D port or the KRE D port, which my preference leaning towards the KRE product. I don't believe you're going to see noticeable gains in a street application with a round port to make the hassle of redesigning your hot side worth it.

__________________
-Jason
1969 Pontiac Firebird
The Following 2 Users Say Thank You to JLMounce For This Useful Post:
  #3  
Old 08-04-2022, 07:03 PM
er455 er455 is offline
Senior Chief
 
Join Date: Mar 2011
Posts: 416
Default

Thanks JL Mounce

  #4  
Old 08-05-2022, 11:37 AM
25stevem's Avatar
25stevem 25stevem is offline
Ultimate Warrior
 
Join Date: Jan 2022
Posts: 1,744
Default

Since both heads have the same valve size and plenty of meat for porting, the limit in terms of the D port head is the area at the Exh flange for bolting up a header bigger then 1 7/8" .to 2".

Since there Aluminum though you could weld and make them the port area needed at the flange to better match what that nice big valve can do.
Doing this you could get round port headers to maybe work, but I don't think it's necessary.


That being said, SBCs with there 1.60" Exh valve make 1100 hp with there Exh port size they can go to when ported, so I don't think if your shooting for 1100 hp with a aftermarket D port head that you will be disappointed.

__________________
I do stuff for reasons.

Last edited by 25stevem; 08-05-2022 at 11:42 AM.
Reply

Thread Tools
Display Modes

Posting Rules
You may not post new threads
You may not post replies
You may not post attachments
You may not edit your posts

BB code is On
Smilies are On
[IMG] code is On
HTML code is Off

Forum Jump


All times are GMT -4. The time now is 05:11 PM.

 

About Us

The PY Online Forums is the largest online gathering of Pontiac enthusiasts anywhere in the world. Founded in 1991, it was also the first online forum for people to gather and talk about their Pontiacs. Since then, it has become the mecca of Pontiac technical data and knowledge that no other place can surpass.

 




Copyright © 2017