When my GMT400 isn't enough...

[BNielsen]

Find a Treasure Yard Vortec 7.4 vehicle. Grab engine, transmission, computer and harness.

Remove your engine and transmission, install Treasure yard parts. Remove your ECM and harness, install Treasure Yard parts.

There's probably more to it than just that--I have no idea how the instrument cluster, ABS, TPMS, and cruise control will appreciate being switched from one ECM to another.

If you can't do this yourself, you might as well pass. Paying a shop to configure all this stuff will cost arms and legs, and if it doesn't run "PERFECTLY" you're going to see a decrease in the resale value because it's a FrankenTruck.





I still say that if you're towing a bigass trailer, you might as well get an '05--'06 Duramax and be done with it. Everything else that involves modifying the 454 or slapping in a 502 or Cummins or whatever is going to be a tuning nightmare with zippity-doo-dah for resale value.

@andy396 could chime in with a little more detail on the difficulty level of doing an L29 swap. But he used the stock harness and integrated it with the stock harness. I know that I probably wouldn't ever do it myself unless it was an absolute gem of a 95 I'd want to upgrade.

Even with the 05-06 (LLY/LBZ) Duramax you'll run into troubles, they were notorious for head gasket issues, as well as a few cooling issues that really didn't get ironed out until the later LBZ and LMM engines.

Man, going through this thread makes me overthink things.

 

[scottydl]

Man, going through this thread makes me overthink things.

You and me both! Haha. But I'm grateful for the dialogue. As you said above, 05-06 diesel sounds cool but diesel problems scare me in a different way. I really have no experience working on diesel engines... even basic maintenance... and I know they are even more expensive to repair when needed.

If I'm going to eventually spend $15k on a replacement vehicle, that could also put me into an 08-09 Suburban 2500 with the then-newer 6.0L. Close to the same towing capacity as what my current 7.4L is rated for.

 

[L31MaxExpress]

My take on this....Get a pair of magnaflow high flow cats for a Vortec 454 and the matching catback for the Vortec. Your later model TBI 454 should be a roller cam engine. The heads, intake and TBI flow fine for your intended use. Put a small "RV" roller cam into it. Next tune the computer. Between the exhaust, cam and tuning you should be able to wake the TBI up equally to a 454 Vortec for alot less money. Heads don't even have to come off. You can swap the springs, studs and rocker arms to make your 454 have an adjustable valvetrain without pulling the heads. You can still make 350-400 hp out of mild cammed 8:1TBI 454 and it will run all day long on 87 octane.

I wouldn't consider a cummins swap but a PSI 8.8 (8.1s big brother) might fit the bill well and makes more HP and TQ than the Cummins 6.7 Stock for Stock. The PSI 8.8 makes peak TQ at 1,800 rpm and peak HP at 3,600.

 

[scottydl]

My take on this....Get a pair of magnaflow high flow cats for a Vortec 454 and the matching catback for the Vortec... a small "RV" roller cam into it... tune the computer...

Will the 96+ Magnaflow direct-fit cat setups (like these at Summit Racing) bolt on to my 95, or would I need something custom made? If you have any other recommended parts sources (or part numbers) for these upgrades, or ideas on who/where might be accustomed to tuning these engines, I would greatly appreciate it.

 

[L31MaxExpress]

A cummins could tow that trailer. And still get you high teens and maybe 25 to 30mpg empty. And no 454 can hang with a cummins towing. The thing about a cummins is turn a knob and turn up the power. Daily reliable 500HP and 1000TQ. Can you say that with gas. (besides laughing gas) but you gotta pay to play. Realistic is 300 to 350 horse and 700tq all stock components. Just change a spring set in regulator. And that with a 3" downpipe and 4" exhaust and she'd be happy.

Down side cummins are loud and proud. There may be no exhaust note but she'll clatter like a tractor. So buy stock in dyno mat lol

Will the 96+ Magnaflow direct-fit cat setups (like these at Summit Racing) bolt on to my 95, or would I need something custom made? If you have any other recommended parts sources (or part numbers) for these upgrades, or ideas on who/where might be accustomed to tuning these engines, I would greatly appreciate it.

I have a set of shorties for a TBI 454 and those magnaflow direct fit cats on my 8.1 in my 99 Tahoe with a matching magnaflow catback.

If you cannot tune it yourself talk with Dave at Old School EFI he is out of Vancouver, Washington. He is much more skilled than the hack job aka Brian @ TBIChips.

 

[someotherguy]

I wouldn't consider a cummins swap but a PSI 8.8 (8.1s big brother) might fit the bill well and makes more HP and TQ than the Cummins 6.7 Stock for Stock. The PSI 8.8 makes peak TQ at 1,800 rpm and peak HP at 3,600.

Ya know, considering the 8.8L is a fairly new engine, it might be a while before they become common enough in boneyards/used market to be attainable for the average dude's DIY swap job.

Richard

 

[L31MaxExpress]

Ya know, considering the 8.8L is a fairly new engine, it might be a while before they become common enough in boneyards/used market to be attainable for the average dude's DIY swap job.

Richard

I dunno they keep showing up on the facebook 8.1 group as rebuildable cores. They have been using them as generators and water pumps for alot longer than the road applications have been around.

 

[someotherguy]

I dunno they keep showing up on the facebook 8.1 group as rebuildable cores. They have been using them as generators and water pumps for alot longer than the road applications have been around.

Average cost of rebuildable core, machine and assembly work, and parts, as well as PCM, harness (as well as general availability), other related necessities to swap in place of a 7.4 TBI?

Richard

 

[Schurkey]

Will the 96+ Magnaflow direct-fit cat setups (like these at Summit Racing) bolt on to my 95, or would I need something custom made?

You'd need the matching set--IF they fit your exhaust manifolds.
https://www.summitracing.com/parts/mpe-95470/overview/year/1996/make/chevrolet/model/c2500-suburban
and
https://www.summitracing.com/parts/mpe-95471/overview/year/1996/make/chevrolet/model/c2500-suburban
~$900 for cats is outrageous, and I own a '97 Vortec 7.4 that probably needs that pair. At whatever point I stuff new cats in place, they'll be "universals" welded into the stock pipes at ~$200.

Maybe you find a Treasure Yard set, I bet you could get 'em for $100.

I'm told that the OEM muffler for the Vortec is very restrictive. Friend of mine said that scrapping the OEM muffler on his '97 7.4 in favor of a pair of aftermarket mufflers made MORE difference than the Gale Banks headers he installed previously.

 

[L31MaxExpress]

You'd need the matching set--IF they fit your exhaust manifolds.
https://www.summitracing.com/parts/mpe-95470/overview/year/1996/make/chevrolet/model/c2500-suburban
and
https://www.summitracing.com/parts/mpe-95471/overview/year/1996/make/chevrolet/model/c2500-suburban
~$900 for cats is outrageous, and I own a '97 Vortec 7.4 that probably needs that pair. At whatever point I stuff new cats in place, they'll be "universals" welded into the stock pipes at ~$200.

Maybe you find a Treasure Yard set, I bet you could get 'em for $100.

I'm told that the OEM muffler for the Vortec is very restrictive. Friend of mine said that scrapping the OEM muffler on his '97 7.4 in favor of a pair of aftermarket mufflers made MORE difference than the Gale Banks headers he installed previously.

I buy through a commercial account at Oreillys. I spent about 1/2 that on the pair. The TBI engines have a restrictive Y-pipe. The Vortecs do not. I liked the option of being able to bolt the system in place only having to cut down the excess length of the pipes going into the muffler (4 door Tahoe is a shorter wheelbase). Magnaflows fitment was very good.
I will gladly spend the money to have good quality stainless stuff because I am done with thin wall steel pipe, crush bends and crappy welds done by muffler shops that fail to account for proper suspension travel.

RockAuto also has the rear section listed above for $229.00 currently. Bosal and Magnaflow are the same product.

Edit, Just looked and the front section is $331 from Oreillys.

Bosal Front 079-4372
Bosal Rear 079-5124