[cadejohnson58]

Hi guys so Im almost ready to pull the trigger on a full exhaust setup. Its a little overkill but I thought I would never have to touch the exhaust ever again and I could grow into it. Right now I just have a stock LT1 in a 95 Impala nothing crazy. I was wondering I have iron heads sitting around I could send out to machine shop and maybe do a camshaft swap with supporting mods of course. I like the 3.08 gear ratio because it cruises quite nice. I have my eyes on a Yank 9.5” full billet 3200 stall converter too.
I do need to do all my suspension probably. Front upper and lower control arms. Its sitting on Eibach lowering springs. I need to find rear trailing arms, Im on stock rims do I need to find adjustable rear trailing arms or just extended? Thank you all, this is a post just to see what you guys would do. Im excited for the exhaust cause mine is rusting away and sounds terrible in my opinion

 

[1slow96]

No point in changing cam ,or converter if keeping the 3.08 gears. 3.73's would be well suited to the torque converter especially.

 

[cadejohnson58]

Well Im not opposed to it. I’ve heard our big cars love the 3.73 makes em feel lighter from a dig. Also heard they cruise pretty well like below 2500 rpm at highway speeds. Thank you for confirming I should look into a rear end swap as well when it comes time

 

[shakenfake]

No point in changing cam ,or converter if keeping the 3.08 gears. 3.73's would be well suited to the torque converter especially.

What kind of reasoning is this?

Spintech offers a full 3" system for the Impalas as well. Don't know what your budget is though.

 

[cadejohnson58]

What kind of reasoning is this?

Spintech offers a full 3" system for the Impalas as well. Don't know what your budget is though.

This is the first Im hearing of this thank you if I can save some money I will

 

[shakenfake]

Also I do second the 3.73 gears but saying that you shouldn't change the cam and TC because of gearing is near nonsensical.

 

[1Slammed96SS]

I recommend Try-Y headers from Dan, @ Clear Image Automotive by far the best headers for our cars, with proven HP #s.

 

[cadejohnson58]

I recommend Try-Y headers from Dan, @ Clear Image Automotive by far the best headers for our cars, with proven HP #s.

He quoted me quad 1’s 304 stainless for $1000. Thank you for your input I might have to think about that.

 

[nsaness]

He quoted me quad 1’s 304 stainless for $1000. Thank you for your input I might have to think about that.

IMO: Quad 1's are too much header for a mild car. Going to Tri-Y's will give the sound and horsepower you want without losing low end torque. All of Dan's headers fit better that anything else on the market, but keep in mind that the Tri-Y's are the only header that is guaranteed to "fit" the Impala.

I have a 396 LT1 and after running numerous dyno simulations for torque profiles, I chose the Tri-Y headers and a 2-1/2" diameter exhaust on my car. Now that my car is finally running (since 2022), I continue to be very happy with that choice.

 

[shakenfake]

Quad 1s are not too much header for a mild car plus you aren't going to feel it in the butt dyno (difference between the two I mean). There is a reason that nobody in the modern era is running mid length headers and the most common primary is 1 3/4". You really are only going to feel a difference once you step up to 2" headers and the torque loss down low is pretty bad.

Considering I was quoted nearly two grand for the tri-ys I would be going with Quad 1s. Dan's Quad 1s will fit.

 

[Marky Dissod]

... this is a post just to see what you guys would do.

First things first: 3.73 & a torque sensing limited slip diff (clutch types eventually need rebuilding).
You WILL regret omitting the limited slip diff. If highway MpG is very important to you, 3.42 & a limited slip diff.
With 3.73 & 255/50R17 - 27" tall tires, 2375RpM ≈ 72MpH, & 2250RpM ≈ 68MpH.
With 3.42 & 255/50R17 - 27" tall tires, 2375RpM ≈ 79MpH, & 2250RpM ≈ 75MpH.

Clear Image Automotive makes the best fitting headers bar none regardless of the size of the primaries.
With Tri-Ys, you certainly get what you pay for. Same goes for the Quad-1s.
If buying headers makes the budget for the rest exhaust kinda tight, maybe Frankenstein the cat-back exhaust system?
Piecing it together can cost less than an outright system.
An outright system may save on labor and time.
Only you can make that decision for yourself.

DEFINITELY have the gears and the reprogramming done before the converter, unless you have already rebuilt the 4L60E.

 

[shakenfake]

DEFINITELY have the gears and the reprogramming done before the converter, unless you have already rebuilt the 4L60E.

Why? You are going to need a reprogramming after the converter anyway.

Unless you are saying do the gears and tune AND THEN think about doing a converter?

 

[Marky Dissod]

Why? You are going to need a reprogramming after the converter anyway.

Unless you are saying do the gears and tune AND THEN think about doing a converter?

Actually, yes, thanks for the rewording.

Gears & tune are the best mods in terms of bang for the buck, both for performance AND potentially improving powertrain longevity.

But I also meant that if the 4L60E has not yet been rebuilt to withstand his plans, doing the converter before the gears may shorten the 4L60E's longevity - which is why one should do gears and programming before deciding whether or not the converter is truly wanted.

 

[shakenfake]

Agreed. Just clarifying

 

[sonuvah]

I'm running Dan's CIA Quad 1 1.75" and cats for several years with much satisfaction. Even though they do have the ceramicoat they are becoming a bit rusty towards the bottoms, and tarnished/dull all over (garage kept always). Mechanically/structurally as solid as the day I installed them. They sound a bit "throaty" mated up to the 2.5" Borla exhaust. However, living in California there is the issue of smog police not passing the car under visual inspection rules. A unique note or sticker may help to get it passed at car registration time. I believe the try-y's would get the same treatment being headers.

I'm also running the 3.73 Eaton posi with a GM 2400 stall HD TC. Very crisp and snappy when launching, but still cruises pretty mellow at freeway speeds. The computer was programmed by B. Herter. However, it needed to be sent back because the tac was off upon return. I hear that if Brian does not do it himself the chances drop that it will be done correctly. There are others who can do the programming for the aftermarket parts on the B-bodies. I would be inclined to try someone different if the need were to arise again. Here's one alternative I saved, but have no experience with him:
https://www.lt1pcmtuning.com/service/order.php

As for the control arms in rear, it would be a good decision to go with the upper and lower adjustable ones so later if you'd like to make ride height and driveline angle adjustments you'll be ready and not have to change them out like I did. Spohn makes both and they're great quality. I just installed (last summer) the rear uppers with spherical bushings on both ends. If you call them Jason will probably be the one you'll speak with and he's very friendly and helpful. Spohn has a lot of other cool stuff for the B-body suspension, too. Just remember, "When you do one mod it's going to require at least three more."😯😒

 

[Snarv47]

What is Brian Herter contact, I as well would like to upgrade to 3.42 with Tune on LT1 mild Rebuild on 949c1.

 

[Caddylack]

No point in changing cam ,or converter if keeping the 3.08 gears.

This makes no sense. You will still see significant gains with stock gearing.

 

[nsaness]

Quad 1s are not too much header for a mild car plus you aren't going to feel it in the butt dyno (difference between the two I mean). There is a reason that nobody in the modern era is running mid length headers and the most common primary is 1 3/4". You really are only going to feel a difference once you step up to 2" headers and the torque loss down low is pretty bad.

Considering I was quoted nearly two grand for the tri-ys I would be going with Quad 1s. Dan's Quad 1s will fit.

Well Cade did ask for opinions, so I gave my opinion. My opinions are based on my experience, and yours seem to differ. I respect your opinion and I don't think either of us is "wrong" here.

For the OP: Torque is far more important to me than horsepower is. I like to get off the line quickly, and torque helps to do just that.
A couple of quick google searches can give you test data to support any side you wish to take. I like Tri-Y's for the torque they make. Full length headers will make more horsepower, but if you are going to stick with those 3.08 gears, you will slow your launches down by going with big diameter and/or full length headers.

Cut and pasted from the below article: "Tri-Y long-tube headers, which were conceived on Shelby Mustangs and Cobras in the 1960s, combine a short primary that is paired with another cylinder that is synchronized in the firing order into a 2-into-1 collector that steps to a larger diameter secondary tube. The two secondary tubes are then merged into a final 2-into-1 collector creating an overall length similar to a 4-into-1 design. The traditional tri-Y works well to build more torque from idle to 4,500-5,000 rpm, making them very effective for street use. Autocrossers and road racers also love them for their midrange torque and increased throttle response."

The Correct-Sized Headers Will Give You the Best Performance

Choosing the correct size and length headers will ensure you get the most torque and horsepower out of your engine and get the best performance

www.motortrend.com

 

[1slow96]

What kind of reasoning is this?

Spintech offers a full 3" system for the Impalas as well. Don't know what your budget is though.

Because both the "bigger" cam and the looser converter respond better to deeper gears.
Far better result with changing the gear,torque converter ,and leaving the cam alone. Less costly also

 

[shakenfake]

Sure but you can do a mild cam and converter and stick with 3.08 gears and you can rock out easily.
I'm not saying 3.08s are awesome, in fact they really suck, but to say flat out no to a cam and converter is wrong.