L29 rebuild - give me ideas

Disclaimer: Links on this page pointing to Amazon, eBay and other sites may include affiliate code. If you click them and make a purchase, we may earn a small commission.

Carlaisle

I'm Awesome
Joined
Oct 14, 2019
Messages
239
Reaction score
277
Location
Required
70hp from just exhaust? That sounds more than a bit optimistic, to me.
Banks did the design work years ago. It's no longer available to buy from them at any price - I tried and they won't make it. Which makes no sense since they already have the engineering done, but whatever. I have a copy of the marketing piece they did for it somewhere. If memory serves, they had 70 HP and 85 lbs of torque on the dyno just from installing their exhaust system. I have the specs on it and will be duplicating when I rebuild my engine.
 

L31MaxExpress

I'm Awesome
Joined
Apr 21, 2018
Messages
5,891
Reaction score
7,540
Location
DFW, TX
Banks did the design work years ago. It's no longer available to buy from them at any price - I tried and they won't make it. Which makes no sense since they already have the engineering done, but whatever. I have a copy of the marketing piece they did for it somewhere. If memory serves, they had 70 HP and 85 lbs of torque on the dyno just from installing their exhaust system. I have the specs on it and will be duplicating when I rebuild my engine.

Thats honestly not too far off. Advanced the stock cam 4° and added thorley TBI tri-ys to my buddies L29 motorhome, with 3" high flow cats into a dual 3" to single 4" merge Y and a 4" diesel exhaust then tuned it. Used the Banks air box and a high flow filter. It picked up about 55-60 gms/sec of airflow across most of the RPM range at WOT. 1 gm/sec is roughly 1.2 crank hp or equivalent to 1 rwhp. It woke it up everywhere in the powerband and required enough additional fuel that it was a good thing he stepped up to LS1 28 lb/hr injectors when he had to replace bad injectors.
 

Carlaisle

I'm Awesome
Joined
Oct 14, 2019
Messages
239
Reaction score
277
Location
Required
A slightly smaller final exhaust would have helped even more. The 454 doesn't produce enough volume to utilize a 4" exhaust properly, especially a long motor home one. 3.5" keeps the temps up more and increases the velocity, which helps immensely with filling the cylinders on the intake stroke where the engine needs it most.
 

Christian Steffen

I'm Awesome
Joined
May 31, 2016
Messages
1,173
Reaction score
431
Location
Green River, WY
Banks did the design work years ago. It's no longer available to buy from them at any price - I tried and they won't make it. Which makes no sense since they already have the engineering done, but whatever. I have a copy of the marketing piece they did for it somewhere. If memory serves, they had 70 HP and 85 lbs of torque on the dyno just from installing their exhaust system. I have the specs on it and will be duplicating when I rebuild my engine.

I wonder if their numbers included any tuning?
 

BNielsen

I'm Awesome
Joined
Sep 6, 2018
Messages
2,632
Reaction score
4,070
Location
North Carolina
I wonder if their numbers included any tuning?

I doubt it; I might know the thing he's talking about, and it was tested on stock trucks if it's the same market piece.
Stock other than the full exhaust kit of course.

I would kill for at least the headers. I contacted Banks to see if they had any stashed away but they didn't; then I asked about the motorhome headers which wouldn't fit even if I had the guts to hack up the ends to fit under a truck.
 

Christian Steffen

I'm Awesome
Joined
May 31, 2016
Messages
1,173
Reaction score
431
Location
Green River, WY
I doubt it; I might know the thing he's talking about, and it was tested on stock trucks if it's the same market piece.
Stock other than the full exhaust kit of course.

I would kill for at least the headers. I contacted Banks to see if they had any stashed away but they didn't; then I asked about the motorhome headers which wouldn't fit even if I had the guts to hack up the ends to fit under a truck.

They were long tubes right? There's gotta be some other good long tube options out there?
 

stutaeng

I'm Awesome
Joined
Aug 7, 2019
Messages
3,410
Reaction score
4,348
Location
Dallas, TX
I have a 1999 CC K2500 with a 454. The truck has 325K on it and it seems that the engine finally gave up the ghost.

I have rebuilt a few engines and have done complete restorations on lots of oddball cars. I have never worked on an engine with so many rebuild options or avenues, and I would love some input.

It's got a corporate 14 and a 4L80E, zero rust and I love the color. I use it as a truck and I need something with lots of torque that wont get stressed out.

Do I buy a stock rebuild or is there a way to make this block better? I would love to rebuild a big block as it is probably the only one I'll ever do.

I have 20psi of compression on #1 and it sounds like a jackhammer hitting a piece of steel while running.



First question I think needs to be asked is: "What is your budget?"
 

BNielsen

I'm Awesome
Joined
Sep 6, 2018
Messages
2,632
Reaction score
4,070
Location
North Carolina
They were long tubes right? There's gotta be some other good long tube options out there?

I think they were kind of a long tube/tri-y combination almost, I haven't found any long tubes that will fit a 4x4 without any serious modifications to them; unless I'm over looking something simple?
 

Supercharged111

Truly Awesome
Joined
Aug 20, 2015
Messages
12,616
Reaction score
15,243
I think they were kind of a long tube/tri-y combination almost, I haven't found any long tubes that will fit a 4x4 without any serious modifications to them; unless I'm over looking something simple?

I believe the Banks headers kept the factory cats, but don't quote me. Stainless Works makes GMT800 8.1 headers that play nice with 4wd. Somebody else be the guinea pig and report back if they'll fit a 454.

https://www.raylarengineering.com/long-tube-headers.html
 

BNielsen

I'm Awesome
Joined
Sep 6, 2018
Messages
2,632
Reaction score
4,070
Location
North Carolina
Top