Headers

[Cbitz233]

Looking for suggestions on a good brand of long tube headers for the 305 in a 83 Avanti. Has anyone installed themselves? 

[Gunslinger]

Short of having a set custom made, I think block hugger types will be all you can find...and even then it may depend whether the inside tubes run outside the outer tubes or inside them for clearance.  I have Sandersen block huggers on my '70.

Edited September 20, 2018 by Gunslinger

[Avanti83]

As Gunslinger has said, there are very few options in headers that will clear the steering box. My question is: Why do you want headers on a 305 of that era? Gunslingers 70 has the output to utilize the improved flow from them but the 305 from your era has many restrictions on performance that headers won't cure.

The ram horn OEM SBC exhaust manifolds are pretty efficient already and there are 2 1/2" versions that Chevy thought could handle way more flow than you have and will fit without clearance issues. I have them on both of my Avanti's. 355 and 383 SBC'S.

I know the headers probably look better but I'd spend my money on upgrades like a better cam and intake and shed the emissions plumbing on the engine topside first. 

Lastly, steel headers will probably dump a lot more heat into an already hot engine compartment and that's not a good thing.

If you are really looking for performance improvements and want to do it right, contact PackardV8 (Jack Vines) on the forum and have him build you a 400 SBC that will really wake up your Avanti. I'll bet you'll get a lot for your buck there compared to a crate engine.

Sorry if I'm coming off as critical I'm just trying to make a point.

Original 83 when I purchased it.

Now

 

My 74 after pulling the original 350 (yup! not a 400) and adding a 383 stroker if you're looking for incentive to clean your's up.

 

Edited September 20, 2018 by Avanti83

[mfg]

I also think the factory Chevy 'rams horn' exhaust manifolds are a good bet on a street car.....also, they're not as obnoxiously noisy as steel headers always get to be!

[Gunslinger]

What's wrong with the noise...the original Avanti may not have had headers but the glass packs sure made a statement.

There's something to be said for a car that the ground shakes under it when you start it.

[mfg]

23 minutes ago, Gunslinger said:

What's wrong with the noise...the original Avanti may not have had headers but the glass packs sure made a statement.

There's something to be said for a car that the ground shakes under it when you start it.

It's not the noise outside the car....it's the drone INSIDE the vehicle that can become annoying!....Just drive around in a car equipped with steel headers for awhile and you'll understand what I mean!

[Gunslinger]

My '70 does have steel tube headers and Magnaflow mufflers...it's a beautiful rumble and tone.  Now side pipes...that's a different story!

[PackardV8]

Whether iron manifolds or tube headers, a V8 can have a 'drone' or resonance at highway speeds.  The better factory exhaust systems have either an H-pipe crossover between the two down pipes or a pair of resonator eliminator cannisters at the rear of the system.

jack vines