Just wondering why not use a 2" primary? Rat motors like them. Or are they not available? If so what about having your flanges opened up to 2" tapering back to the 1 7/8 before the weld. Its only 0.625 per side. If your flange is stainless you could use a 60* included carbide cutter. clean the flange up too .250 deep and you will have a 2.0 opening so even if the header bolt patterns (or worse) are a little off you will still have a good amount of transition room. Ill be cleaning mine up with a 30* cup wheel.

 

They're available, from ARH, and since I have ARH's already, they'll fit rough up to my X pipe. If the fit doesn't interfere with my starter on the passengers side by the starter, that's what I'll do.

 

I just swapped from 1 7/8" to 2" ARH. The 2" are nice but overkill for this setup and 7/8" I think would work better.

I made 1050rwhp on 7/8" and went to 2" just to see if I can crack 1100rwhp.

 

Ok, good advice from experience! I just want to take all blaming points away, and want as much HP as this setup can make before swapping internal pieces.

 

Can 2" vs. 7/8" actually hurt this setup? I haven't read much on it - just curious.

Thanks

 

Maybe slightly down low with torque, but I don't need more torque down low! I can blow the tires off past 80 if I desire. I'm going to talk to my head porter tomorrow and see what his thoughts are. From there, I'll buy a set.

 

How about a make believe 3 step...1.875/2.0/2.125 with a 3.5" merge collector and a spike....tig welded stainless. I mean hey it's your money I'm spending....LOL
Why wouldn't a fire breathing dragon like yours just love a big primary pipe?
If simple H/C 346s seem to prefer 1 7/8 over 1 3/4.......you have almost 27% more air pump.

 

Lol! Great logic though seriously. I know this isn't FI, but it is a big air pump.

 

Here bigger is better I would think.... Just to clear Franks phat round exhaust ports. lol

 

Solid results man. I know it feels strong. Need to go ahead and swap the headers and intake and throw some R888's on the rear.

 

Thanks! The headers have been ordered. It'll be awhile before the intake is thrown on. Annnnddd, I got a hell of a deal on NT01's so I'll be throwing those on this month as well.

 

Hey man did you up load a vid i didn't see one. Also have you decided on the bigger cam?

 

2" ARH's arrived today! Straight up big gnarly headers. Off to coating tomorrow, and hopefully on this weekend! Hope to pickup some good HP with these bad boys!

 

Gotta love the 2" primaries!!

 

Are you throwing them on yours? They're not playin' that's for sure. Big ol' ports ready to move some air.

 

Yeah I got them to make a set to fit in the chevelle...they are some killer pieces for sure!!

 

427zm when everything is finally perfect the way you want it feel free to park in my garage thanks lol jk how loud is the car?is it still bearable to drive?

 

Currently, it's a joy to drive. The stock TI exhaust is great, quiet cruising, but roars when you get on it.

 

https://ls1tech.com/forums/attachmen...1&d=1397583202

I'm going to have to go with 2'' primary's also. Even the gm ls3 cnc exaust ports are way to big for 1-3/4 od tubes. They just came in today.

 

You have a flow sheet for the FRH heads that show the .100-.700 range?