LS or old school?

[xKid4x4s]

hey there guys/gals. I have a 1994 chevy shortbed 2 door truck, and Im taking the TBI engine and trans out, And I wanted to know if I should go with a stock junkyard LS or I already have a re machined new 355 with 2.02 heads from an early 80s truck and the heads came from a camaro.

I was debating an LS styled engine because I want DECENT fuel economy and good power, but I already have the 355 just begging to be put in it. If I did the 355 I would put a FAST EFI system on it, and it would have a 4L80 with Overdrive anyway.

so my real question is, would the 355 with overdrive and efi be able to compete at all with a junyard stock 5.7 LS style engine?

thanks everyone in advance

[GM-power]

I'm assuming you'll be using the efi on the ls? For me if I had that choice, I'd go ls for sure. Just stock I'm sure it'll outperform the 355 your thinking of putting together. Is the block from a 80s truck and the from the camaro, kinda confusing how you wrote it. Anywho old school stuff is fun but a mild 355 couldn't touch a ls imop.

[TJ's Chevy]

Old school for ease of workmanship.
LS for modern technology and better fuel economy.

[toolboxchev]

Originally Posted by tj's chevy

old school for ease of workmanship.
Ls for modern technology and better fuel economy.

x 2

[xKid4x4s]

yeah sorry the block is from probably a late 80s truck, and the heads are from an early camaro. thanks for the reply

[GASoline71]

"Camaro" heads means nothing. It could be any kind of head.

You can get decent fuel mileage out of either. Depends on how you tune and your driving style.

Gary

[cableguy0]

I would go LS for sure. Probably wouldn't bother with the first gen 5.7ls I would find a 5.3 myself. The ls might actually be cheaper by the time you buy the fast fuel injection and the controller for the 4l80 in the older truck. The Ls with a cam upgrade will run circles around a 355 in both power and mileage.

[xKid4x4s]

Originally Posted by cableguy0

I would go LS for sure. Probably wouldn't bother with the first gen 5.7ls I would find a 5.3 myself. The ls might actually be cheaper by the time you buy the fast fuel injection and the controller for the 4l80 in the older truck. The Ls with a cam upgrade will run circles around a 355 in both power and mileage.

I suppose your right, The 5.3 I heard pretty great things about it, but im running 36 inch tires and 3/4 ton suspension and diffs, so maybe something a bit bigger, I once had a 6.0 HO, maybe I can find one of them. thanks

[cableguy0]

Don't get worried about the cubic inches with the ls engines. Most 4.8's are making more power than a cammed 350. The 5.3 is more than capable and will get decent mileage. The 6.0 is a tad more thirsty and obviously will make more power but the 5.3 can easily make 400-450hp with doing a lot of work to it. The 6.0 will be a lot easier to find with a 4l80e already attached though. Whatever you get make sure you get everything. The accessories, wiring and computer. The little stuff will eat you alive at the auto parts store.

[xKid4x4s]

Originally Posted by cableguy0

Don't get worried about the cubic inches with the ls engines. Most 4.8's are making more power than a cammed 350. The 5.3 is more than capable and will get decent mileage. The 6.0 is a tad more thirsty and obviously will make more power but the 5.3 can easily make 400-450hp with doing a lot of work to it. The 6.0 will be a lot easier to find with a 4l80e already attached though. Whatever you get make sure you get everything. The accessories, wiring and computer. The little stuff will eat you alive at the auto parts store.

Okay I think you convinced me LOL, so for the wiring, can I cut the harness where it goes into the fire wall? what do I need from the harness. thanks

[cableguy0]

DONT CUT ANYTHING. The engine harness will be one piece. Take everything including the fuse panel if you can get it. All of the engine wiring is under the hood. Take the oxygen sensor too if you can. Don't know what your skill level is but you can either do the harness yourself or send it and the computer out. The computer has to be tuned to remove the vats system as well as delete some of the emissions stuff.

[xKid4x4s]

Right i know to take all the engine gear but all that harness under thr dash is difficult to remove and im fairly sure i wont need all of it. Just not to sure on what i dont need from that side of the harness and what i do need. I know the fuse box under the hood connects to the one in the truck ao do i also need that fuse box too? Thanks

[cableguy0]

You don't need the interior harness except for the Data link connector. Many junkyards sell complete take outs on ebay. I would search around. The underhood fuse block is the one that would make your like easier. That's where the engine gets it powers from. It would also contain the ciruits for a fuel pump and even electric fans depending on the year of the truck.

[xKid4x4s]

Alright thanks i appreciate it. Happy holidays

[xKid4x4s]

..

[4 Wheelin Fudpucker]

Id not run 2.02 heads on the street with unleaded fuel. They crack between the valves.
You need to run Duralt lead additive, which may not be made any more.
1.94s are big as I run, for the last 40 years or so.

[GASoline71]

2.02's with hardened valve seats are just fine on the streets.

Gary

[Marv D]

Ya know, this hybrid thing is really starting to intrigue me. I'm not sure I can justify the one-off pieces and the cost,,... well..... yet.

I think I'm going to have to build one, put it ion a dyno and see what the $ per pound of torque ends up. The LS power and reliability in a standard tried and true SBC bottom end

I wouldn't do a carburated version for anything but a drag motor,, but the possibilities of a stock LS EFI top end on a 4" stroke SBC with something like the AFR mongoose heads just gives me a tremble in the knees.

[GASoline71]

Originally Posted by Marv D

I wouldn't do a carburated version for anything but a drag motor,, but the possibilities of a stock LS EFI top end on a 4" stroke SBC with something like the AFR mongoose heads just gives me a tremble in the knees.

With our brains and your money... we could do this!

Gary

[68post]

Originally Posted by Marv D

Ya know, this hybrid thing is really starting to intrigue me. I'm not sure I can justify the one-off pieces and the cost,,... well..... yet.

I think I'm going to have to build one, put it ion a dyno and see what the $ per pound of torque ends up. The LS power and reliability in a standard tried and true SBC bottom end

I wouldn't do a carburated version for anything but a drag motor,, but the possibilities of a stock LS EFI top end on a 4" stroke SBC with something like the AFR mongoose heads just gives me a tremble in the knees.

I think its a great concept, and truly is the "best of both worlds". A great aftermarket block that is needed for a high output old school sbc build, ease of installation with the affordability of the Gen-1 bottom-end components, and the great flowing LS heads of your choice. What's not to like !?

I assume there are LS swap headers for a square body out there ??
edit; I see 2wd swap headers, they're a little salty but not a game changer.