Considering a Gen V Swap into my '77

[Adam ellis]

A little while ago I posted about putting a 502 in my '77, but since then I have decided to change my project to a Gen V swap as it will suit my desires better. I am planing on doing a Gen V swap with either a 6L80 or possibly an 8L90 in my '77 C20, I was wondering if anyone had a suggestion on a retrofit column that would allow for the proper amount of gear select positions. Ididit columns all say they will work for the three and four speed automatics, but nothing about the six speed (or greater) auto. Also is there any other components to add to my list to look for, this project is still in the planning stage and may take a little while as I am still in college, but I want to have a good grasp of what I need so I can snag any deals that pop up. I would also be interested in knowing of any common issues with these swaps so I can be prepared. Any help is appreciated!

 

[bucket]

Do the newer trucks with 6+ speeds actually have that many positions on the shifter? Or do they only have a select few positions with + and - buttons for manually selecting lower gears?

I hope you plan to leave the GenV 454 completely stock, with an extremely mild "RV" type cam as the only upgrade. The reason I say this is because they are a bit of a bastard engine and just trying to make a mild performance build out of one sends you down a rabbit hole. The kind of rabbit hole that has you replacing everything and spending a bunch of money as if you were going for an all-out performance race engine. So if you plan on a basic hop up, it's much cheaper to start with a markIV or a GenVI.

 

[Adam ellis]

The plan was to keep the 5.3 stock as possible, just retrofitting it. Im not actually sure about the positions, I will have to find a way to get a peek in one of that era to find out.

 

[idahovette]

We talkin Big Blocks or Small Blocks or LS engines here??

 

[Catbox]

Looks like LS platform engine from the 5.3 he mentioned.

 

[idahovette]

He started out with 502, then Gen V, now 5.3?? Then Andy told him use a Mark IV or Gen VI

 

[Craig 85]

My 2010 Denali had a 6.2 the 6L80. The gears are manually shifted with the +/- button on the column once you move it from D to M (manual). It also had the Tow/Haul mode which was nice when towing my pontoon. The trans will down shift on it's own when decelerating or braking.

 

[Bextreme04]

Well, a Gen V small block would be an LT technically, not even an LS. The only 5.3L LT engine is the L83 that was available in the 2014 and newer 1500 Tahoe/Silverado/Suburbans. They are direct injection and have almost no cross-compatibility with LS(Gen III/IV) small blocks.

The biggest issue you will run into with this kind of setup will be the lack of tuning options. Everything for them is expensive and I personally don't like the 6L80 or 8L80 in the factory tune. Chevy actually sells the engine/trans/ECU and full wiring harness as a big kit for retrofit applications. A buddy of mine just ordered one for his '73 Nova.

 

[Bextreme04]

As craig said, the shifter would have the same number of spots as a TH350/400 column and would have buttons to manually(electronically) shift it up or down. The 6L80 is the first fully electronic transmission from GM and has the trans controller inside the transmission. It still has a rooster comb and shift linkage, but that only selects between PRND, not the 6 gears.

 

[Bextreme04]

Here's the Chevy connect and cruise system. https://paceperformance.com/i-23836...-6-speed-auto-transmission-combo-package.html

This is the exact setup you were talking about, right? Its probably cheaper to get a wrecked vehicle or engine/trans combo used from a junkyard, but you would also need something like HP tuners or EFI Live to make adjustments. I don't know if any aftermarket systems can control the VVTI and direct injection systems.

 

[idahovette]

That's all well and fine, but first we need to know what power plant he is gonna go with. If you start at the first post it's BBC, then after Bucket's post it goes to "5.3", so where are we????

 

[Bextreme04]

That's all well and fine, but first we need to know what power plant he is gonna go with. If you start at the first post it's BBC, then after Bucket's post it goes to "5.3", so where are we????

Well, he said that he originally wanted to do a 502, then switched to wanting to do a Gen V and 6L80. Then he clarified it to be Gen V 5.3, which narrows it down to only being an L83, Gen V, LTx engine.

 

[Adam ellis]

To settle the debate about what engine I am planning on the Gen V L83 which is a 5.3L. I am planning on buying a scrapped donor vehicle for the swap, and using all the computers and such off of that, then just getting a retrofit harness. Thanks for the input on the transmission question. This is a long term project, so I'll try and keep updating here whenever I work on it.

 

[idahovette]

OK so I'm old and pretty much set in my ways. If I don't see numbers for displacement my old Chevy history kicks in, so that's where I got screwed up.....Gen V, Gen VI, LS....just give me my old 327s, 396s and 427s and I'll be happy......327=SBC....396 and 427=BBC, ok I'm done???

 

[Bextreme04]

OK so I'm old and pretty much set in my ways. If I don't see numbers for displacement my old Chevy history kicks in, so that's where I got screwed up.....Gen V, Gen VI, LS....just give me my old 327s, 396s and 427s and I'll be happy......327=SBC....396 and 427=BBC, ok I'm done???

Now especially it is getting less and less dependent on displacement. An LSX 454 is a..... small block. GM hasn't made a big block in a production vehicle(outside medium duty and above) since what... 2004? That's when the 8.1L was no longer offered as an option on even 3/4 and 1 ton vehicles. I think you could get it in the topkicks up through 2008 or 2009, and then it was completely phased out. You can still get them from GMPP or aftermarket, but even that is slowing down as these high displacement small block LSx and LTx engines are leaving them in the dust with power, longevity, and efficiency.