Neal Humby

Hi guys...just bought a new set of Hooker Headers #2138-1 ceramic coated
long tube headers...1 5/8" primaries/2.5" collectors

Now I need advice on collector extensions, straight pipes and mufflers!

I'm installing these on a 1986 Camaro Berlinetta, with 305 carb.

Any facts/ info would be appreciated,

Neal Humby

five7kid

iTrader: (14)

Those route via the stock exhaust routing. Your best bet would be to have an exhaust shop (not a muffler shop) build the pipes to the stock cat location with 2-1/2" mandrel bent pipe, joining them with a good "Y" like the Flowmaster 2-1/2" into 3", and run a good 3" cat-back for the rest of the exhaust (Hooker Aerochamber, Magnaflow, Dynomax, etc.).

Neal Humby

Thank you for your reply...I was really hoping to setup a true dual exhaust.

Because both headers point to passenger side, what collector extensions
would work for two separate pipes back to two mufflers?

91z 2 8

a 305 dosent make enough power for true duals jsut do single 3"

Neal Humby

so...2.5" to 3" y-pipe to hi-flow cat to flowmaster __________ (fill in blank,
please) ??

(Pooh, I wanted true dual)

five7kid

iTrader: (14)

Were you planning on running true duals via the stock routing?

Really, though, you won't gain any performance, and you'll spend a buttload more money on true duals vs. a single 3" aftermarket cat-back.

Do you have your heart set on Flowmaster? If so, get one of the American Thunder cat-back systems. The '86-'90 TPI single cat application would be best.

Neal Humby

I was going to do what "my cheap, deathly sounding exhaust" (in this webpages search) did...Will i gain any performance with the headers???

91z 2 8

yea you should gain some nice HP with the LT's if im not mistakenif you really want true duals mabye you could do 2inch stright pipes lol or mabye 1.5" and really big tips

five7kid

iTrader: (14)

Read this again:

Mongoose

iTrader: (2)

I was considering those headers at one time, let us know how the install goes (with pics if possible please).

Neal Humby

Ok, I read that again! but can someone explain why the 305 gain is negligible? (my tach redlines at 5500)

I was hoping for better fuel economy at low revs and more horsepower at higher revs...

I seems I'm better off with that friggin y-pipe...just hate the way you see
it from pass side...perhaps a custom y-pipe and hi-flow cat wouldn't be
as noticeable....I'm still open to any suggestions!!!

Mongoose

iTrader: (2)

Well, they seemed to help when GMPP used them during an LT1 install on the prototype 25th anniversary Z28 some years back. I know this is neither here nor there but I always thought ANY header would be better than a stock manifold.

five7kid

iTrader: (14)

I was speaking to 91z 2 8 with regard to his comments about straight pipe and the like.

The gains are negligible because other restrictions remain, such as the factory low-lift cam, single snorkel air cleaner, 2-1/4" cat & cat-back. The headers will help upgrades to those parts work even better, but if you don't do anything about them, the improvement from the headers alone will be negligible. The 1-1/2" primaries of the 2138HKR's work well with a 305 and will maintain higher exhaust speed, which improves low-RPM response and fuel economy.

You want to see things dangling down in an ugly way, go true duals.

Neal Humby

I appreciate the thoughts Five7kid. I have already got rid of the stock intake.

Now have edelbrock top breather on carb and will go 2.5 to 3 inch from Y pipe
back...will that help a little?

five7kid

iTrader: (14)

The top breather doesn't help much because it sits right in the hood blanket, and it's just letting in hot underhood air. A dual snorkel air cleaner that scoops cool air from the front of the hood is a much better set-up.

The stock intake isn't restrictive until you do other upgrades such as cam.

3" from where the two banks join on back along with the headers will help. Just don't keep the 2-1/4" stock cat in there.

A cam upgrade, along with headers & exhaust, dual snorkel air cleaner, and intake upgrade will really wake the car up.

Neal Humby

You are a wealth of knowledge five7kid! OK, I'm going out on a limb here...what cam would you recommend? Does a cam change mean other parts too?
I probably won't do it right away, but I could setup the exhaust now, right?

five7kid

iTrader: (14)

The more modern grinds like Comp XE, Crane Compucam, etc., work pretty well with other mild upgrades. A Comp XE262 would work with headers & air cleaner upgrade. Any bigger than that, and you'll need a higher stall torque converter (although even the XE262 would probably respond well to more stall).