What are the power limits of a 1 3/4 stepped to 1 7/8 with 3 1/2" collector.
04-06-2012, 06:30 PM
#1
What are the power limits of a 1 3/4 stepped to 1 7/8 with 3 1/2" collector. Here is the deal. I habe a 63 Chevy Pick up with a 418ci LS in it. It made 521rwhp / 469ftlbs NA through a locked up 80E with:
11.1cr (72cc AFR 225's, -4cc piston, .045" gasket)
245/260 106icl 109lsa .646/.629 custom grind
Super Victor intake
NX 2 stage plate
4150 to dominator adapter
Dominator TB
EWP
UD Pulley
Edelbrock 1 3/4 stepped to 1 7/8 with a 3 1/2" high velocity collector for 4th Gen F-bod's
I think I might have been leaving power on the table with the headers both NA and most likely worse yet on the bottle.
I recently sold the heads to a buddy and went with a set of PRC 237's. With a 58cc chamber and a .051 gasket I am at about 12.9cr. I also put a new bumpstick in it 254/260 111icl 113lsa .630/.625. I am planing on running E85 now.
I am guessing that with the added volume of fuel for the E85 that I am probably leaving even more power on the table by leaving burnt gasses in the chamber. Add N20 to it and probably makes it worse. The plan is to use the 2 stage kit, first stage at 150, second at 150 moving to 250 at some point (300-400 total). All of this will be with E85.
I tried fitting a set of Kooks 2" primary with 3 1/2" collectors in the truck and both of the collectors kick out too far and hit the frame.
I tried a set of 1 7/8 Kooks headers for a TBSS as I have seen another guy use them with sucess in an older truck. The header would fit the truck fine, but the front primary tube makes a drastic bend and does not fir the PRC 6 bolt head. It passes right through where the 2nd and 3rd ear are located. Sure I could cut them off since I am running a LS3 block, but I feel that would be a waste if I ever wanted to sell the heads or go to an aftermarket block.
Being that I run a motor/mid plate I need something that drops decently quick after the last cyl's and fits the 6 bolt head and truck frame.
So this brings me back to running the Edelbrock for now until I can find something.
After my long story here, I am curious to know is anyone is making upwards of 800rwhp through a 1 3/4 stepped header?
Any other suggestions on headers to try?
11.1cr (72cc AFR 225's, -4cc piston, .045" gasket)
245/260 106icl 109lsa .646/.629 custom grind
Super Victor intake
NX 2 stage plate
4150 to dominator adapter
Dominator TB
EWP
UD Pulley
Edelbrock 1 3/4 stepped to 1 7/8 with a 3 1/2" high velocity collector for 4th Gen F-bod's
I think I might have been leaving power on the table with the headers both NA and most likely worse yet on the bottle.
I recently sold the heads to a buddy and went with a set of PRC 237's. With a 58cc chamber and a .051 gasket I am at about 12.9cr. I also put a new bumpstick in it 254/260 111icl 113lsa .630/.625. I am planing on running E85 now.
I am guessing that with the added volume of fuel for the E85 that I am probably leaving even more power on the table by leaving burnt gasses in the chamber. Add N20 to it and probably makes it worse. The plan is to use the 2 stage kit, first stage at 150, second at 150 moving to 250 at some point (300-400 total). All of this will be with E85.
I tried fitting a set of Kooks 2" primary with 3 1/2" collectors in the truck and both of the collectors kick out too far and hit the frame.
I tried a set of 1 7/8 Kooks headers for a TBSS as I have seen another guy use them with sucess in an older truck. The header would fit the truck fine, but the front primary tube makes a drastic bend and does not fir the PRC 6 bolt head. It passes right through where the 2nd and 3rd ear are located. Sure I could cut them off since I am running a LS3 block, but I feel that would be a waste if I ever wanted to sell the heads or go to an aftermarket block.
Being that I run a motor/mid plate I need something that drops decently quick after the last cyl's and fits the 6 bolt head and truck frame.
So this brings me back to running the Edelbrock for now until I can find something.
After my long story here, I am curious to know is anyone is making upwards of 800rwhp through a 1 3/4 stepped header?
Any other suggestions on headers to try?
04-07-2012, 04:45 AM
#2
I have the Kooks stepped. The 550 number was made through a cutout located past the rear axle so not a great location. I have since changed the exhaust to 4" cutout just at the end of the merge so with the 102 intake and this I'm hoping for decent gain. This will probably put the headers to the limit though.
