I'm about to write Hooker, but thought I'd try you guys first.

Received my 2055s yesterday from Summit (finally - took 6 weeks). The good news: AIR & O2 connections, all hardware, good looking y-pipe w/2-1/2" down pipes to 3" @ convertor, welded-on plate w/EO #, generally good looking quality.

The shakey parts: Pipe dimensions are OD (1-5/8" primary OD nets ~1-1/2" ID, etc.); ports don't exactly match the gaskets (which they provided); and the biggest surprise, at the collector, the opening is only 1.9"! It is a ball-joint to the y-pipe, and I can understand them wanting to make sure you get a good seal, but that seems like an awful restriction.

I'm tempted to get out the die grinder and open those collectors up to at least 2.25". Is it possible, though, that they actually work better with that small opening? The rest I think I can live with.

What do you all think?

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82 Berlinetta, orig V-6 car, now w/86 LG4/TH700R4. 2.93 limited slip. Cat-back from '91 GTA, Accel HEI SuperCoil. AMSOIL syn lubes bumper-to-bumper. Daily driver, work-in-progress (LG4 w/'87 LB9 block, ZZ3 cam and intake, World 305 heads, Hooker headers & y-pipe, 3" Catco cat & 3" cat-back).
57 Bel Air, my 1st car. 0.030 over 396, 9.7 CR forged TRWs, Weiand Action+, Edelbrock 1901 Q-Jet, GK 270 cam, Magnum rockers, Jacobs Omnipack, 1-3/4" Hedders & 3" Warlock header mufflers, TH400 w/TCI Sat Night Special conv & Trans-Scat shift kit, LT MegaShifter, 3.08 8.2" 10-bolt w/Powertrax, AMSOIL syn lubes bumper-to-bumper. Best 15.1/95.5 @ 5800' Bandimere.

 

I've been wondering that too. my ports are 1-5/8" high so I dunno why yours aren't but the ball connection was curious. I figured that all the pipes don't flow at once so maybe that helps with scavanging. they SHOULD know what they're doing but I'll be glad to hear the reply they give you

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-Tas
'89 Formula WS-6

305, TBI, auto, 14x3 chrome flat based open element with K&N, Milodon 160* thermo, functional Formula hood, cross-flow Flowmaster, '99z28 rear pipes and tips....

Soon to be installed:
Hooker 1-5/8" 50 state legal headers, Dynomax 3" I pipe (PN 44063 and 43248), Catco 3" cat, and injector spacer.

Super GRK_Taz World
F-Body Dual Exaust
EFI & Intake Options
AOL IM: superGRtaz

 

Just remember the old saying. "A chain is only as strong as it's weakest link."

Any where on your exhaust that gets smaller will tell the engine that it's the size of the whole exhaust. I read about this in a book that a race engine builder wrote. He said a lot of people will run 2.5" pipe into 2.25" mufflers w/reducers because they are cheaper. Well they might as well run 2.25" pipe then.

If you enlarge the connection, just make sure it will seal properly. I don't know if the above is true about one very small portion of the exhaust, but I can't imagine it would. The pipe thickness is 1/16" so I doubt if it'll hurt going to 2.25" opening.

Another fact he stated. He's done dyno tests, and mandrel bends don't help flow. Mainly because the air flows on the outside of the bend. The dimples are on the inside of none mandrel bends. The only loss I can see though is that a dimpled bend will reduce the diameter of the pipe. But this guy knows what the dyno said. Maybe it just wasn't enough of a loss to worry about. Like .5-1hp or something.

 

I was just measuring the diameter of the primary pipes in a round section, not the ports themselves. The openings in their gaskets are slightly smaller than the ports on the World heads; I thought I'd just clean up the gaskets to match the ports, then clean up the header ports to match the gaskets.

I'll post Hooker's response, but if anyone else has an idea, let's hear it.