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Iroc 5.7 vs ls

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Old May 1, 2024 | 04:33 PM
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Iroc 5.7 vs ls

Hi guys , I’m looking for advice and or opinions! I have a 1986 IROC Camaro. 305/ auto. Bought without the engine. I’ve worked with small block chevys all my life and thought of possibly going to the LS engine. 4.8 / 5.3 or 5.7 . You can’t help not hearing how great these are and I’m sure they are. However Hawks 3rd gen tells me I’m looking at 4 to 5000 for the swap alone and while people say these are cheap engines I can’t find one in decent shape for less that a grand. Bottom line with all the hassle of the LS engine is it worth the time and$ to do ? I have a zz4 350 in another Camaro and it runs great ! Thanks again
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Old May 1, 2024 | 05:22 PM
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Re: Iroc 5.7 vs ls

The engine itself is the cheapest part of the swap

While they are fantastic powerplants, be sure you really want to use one before tearing anything down. If you've been happy with SBCs in the past, then don't overlook the 305 you already have
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Old May 2, 2024 | 07:16 AM
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Re: Iroc 5.7 vs ls

Stay with a gen 1 sbc preferably a 350. i think you will be happier and have a cheaper more simple straightforward swap
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Old May 2, 2024 | 09:18 AM
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Re: Iroc 5.7 vs ls

Every swap is 4-5k so pick what you want to work on.
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Old May 2, 2024 | 09:33 AM
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Re: Iroc 5.7 vs ls

Depends on what you want out of the car.

The more you drive it, the more you'll benefit from the newer motor. The LS engines are better in every way than the old SBC.

OTOH, swapping to one is often ALOT more work and money, than an upgraded SBC. $4-5k for a full F body pullout is probably about right. You can get a truck one, 4.8 / 5.3 / 6.0 w 4L60E, for maybe $1.5-2k. But then you have to deal with exhaust, mounts, tuning, etc. But a ZZ6 (current equivalent to ZZ4) is in the same $4-5k range.

Alot also depends on how much of the work you can do yourself. Paying somebody to swap to something that's in effect a "foreign" engine (to the car at least), is NOT cheap.

How soon do you want it running? Are you riding the bus to work? Or is this just gonna be a pretty-Sunday-afternoon playtoy?

You don't tell us how much of the car is still there; wiring, exhaust, etc. You don't tell us if it still has the transmission, or if so, if it's any good. The more of that that's missing or needs replacement, the more it tips the balance toward a LS, simply because you have to buy it anyway, and it just becomes a choice of which one you order.

For a car with no motor or trans I'd probably look real seriously at a truck LS pullout. I'd shoot for a good one: best to get would probably be about a 05 - 06 Escalade LQ9 w/ 4L65E. You haven't told us enough to really go on, though.
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Old May 4, 2024 | 02:06 AM
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Re: Iroc 5.7 vs ls

Once you reach a certain power level, you're doing all the same supporting mods regardless of which engine is in the car. If going naturally aspirated LS engine, then I would suggest 6.0L or larger. It's so much more a hot rod with those engines.
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Old May 6, 2024 | 10:52 AM
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Re: Iroc 5.7 vs ls

Originally Posted by Lisa Keefer
Hi guys , I’m looking for advice and or opinions! I have a 1986 IROC Camaro. 305/ auto. Bought without the engine. I’ve worked with small block chevys all my life and thought of possibly going to the LS engine. 4.8 / 5.3 or 5.7 . You can’t help not hearing how great these are and I’m sure they are. However Hawks 3rd gen tells me I’m looking at 4 to 5000 for the swap alone and while people say these are cheap engines I can’t find one in decent shape for less that a grand. Bottom line with all the hassle of the LS engine is it worth the time and$ to do ? I have a zz4 350 in another Camaro and it runs great ! Thanks again
If I had to do mine all over again I would've just gone to a big block and hit it with a few pounds of boost. LS are amazing engines and they make big power but definitely be prepared to spend some money.

Once you get the engine do you keep it NA or boost it?? Depending on which way you want to take your build the costs can balloon and suddenly you're $30k deep
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Old May 15, 2024 | 07:28 PM
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Re: Iroc 5.7 vs ls

Thanks for your advice, I’m sure the LS is a great engine how ever I just don’t see any clear advantage to it for the $. The 86 iroc I have is complete minus engine, I just can’t see putting 6 or 7 grand in this thing just to have an LS engine. I’ve always been a small block fan so I’ll just build a 383 and see how that goes. Thanks again!!
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Old May 15, 2024 | 07:31 PM
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Re: Iroc 5.7 vs ls

Originally Posted by Lisa Keefer
Thanks for your advice, I’m sure the LS is a great engine how ever I just don’t see any clear advantage to it for the $. The 86 iroc I have is complete minus engine, I just can’t see putting 6 or 7 grand in this thing just to have an LS engine. I’ve always been a small block fan so I’ll just build a 383 and see how that goes. Thanks again!!
Build a 427 SBC with a big lumpy cam and great heads
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Old May 15, 2024 | 07:33 PM
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Re: Iroc 5.7 vs ls

Sounds a bit much but Thanks for your response
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Old May 16, 2024 | 08:51 AM
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Re: Iroc 5.7 vs ls

Originally Posted by sofakingdom
Depends on what you want out of the car.

The more you drive it, the more you'll benefit from the newer motor. The LS engines are better in every way than the old SBC.
this is so true of a statement and forget for a moment anything to do with power levels... part of the fun factor is certainly the mod etc, but then the fun factor is something you can reliability drive!

just some quick thoughts on practical reliability that i experience between my 3rd gens that are SBC vs LS

- LS = no intake manifold water leaks and better sealing all the way around vs weap, seap, leak of SBC on everything over time
- LS = no ICM or other ignition failures that leave you stranded
- LS = starter that can be swapped without wondering is the shimming correct for the new one that will eat your flywheel ring
- LS = ECM (assuming OEM swap) with great tuning ability and great diagnostics
- LS = design tolerances built in that allow you to swap intakes, etc with almost certainty that parts fit right vs get out the grinder, welder, etc to make things work
- LS = better, better, better long term durability all the way around of a base motor, ie 100k junkyard motor can easily be found that is a great base

so my latest project is SBC that has already had a intake water leak ... why didn't i listen to my own advice! i like wrenching but now that it is summer i am swearing!
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Old May 16, 2024 | 03:51 PM
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Re: Iroc 5.7 vs ls

LS engines are easier to work on and more simple frankly.
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Old May 16, 2024 | 06:23 PM
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Re: Iroc 5.7 vs ls

Originally Posted by Lisa Keefer
Hi guys , I’m looking for advice and or opinions! I have a 1986 IROC Camaro. 305/ auto. Bought without the engine. I’ve worked with small block chevys all my life and thought of possibly going to the LS engine. 4.8 / 5.3 or 5.7 . You can’t help not hearing how great these are and I’m sure they are. However Hawks 3rd gen tells me I’m looking at 4 to 5000 for the swap alone and while people say these are cheap engines I can’t find one in decent shape for less that a grand. Bottom line with all the hassle of the LS engine is it worth the time and$ to do ? I have a zz4 350 in another Camaro and it runs great ! Thanks again
It was asked somewhere above but worth asking again.
I've debated this very issue myself and have assembled a cost analysis.
Questions though are what are the performance objectives and intended use of the car?
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Old May 17, 2024 | 09:14 AM
  #14  
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Re: Iroc 5.7 vs ls

I have an '83 Z28 that I bought as a roller. Prev owner had (drag?) raced it with some type of SBC, already had a 4:10 posi in the stock rear-end. I swapped in a 6.0 and have somewhere between $6K-8K into it (stopped counting after $5,500 .... lol). Granted I didn't "have" to buy the roll cage, belts, stereo, newer seats, etc.
Roller - $800
Engine - $600 (bought a crashed Denali truck $1200 for the 6.0 and wire harness, sold some parts and scrapped it to get some money back)
All the remaining costs are parts, lots and lots of parts add up. Including new fuel tank (newer year, same fit, uses newer fuel pump style for the higher pressure needed), all new fuel lines, low profile oil pan, car style water pump and accessory drives, belts, hoses, radiator, relocated battery to trunk. Stainless headers, all custom stainless exhaust that I fab'd myself. Roll cage that I installed myself. Trans cross member that I fab'd myself (to be able to use a 4L60E with the rear diff torque arm). Modified a used hood to clear the truck intake, engine remained stock, slight tune. All this to say that I did a lot of the work myself and it still costs a lot of money. Transmission was used and needs a rebuild. Rear end is stock 10 bolt and wont last with much more power. So I could still spend another $4K+ just for some durability and dependability. Car is loud and kind of obnoxious, goes like crazy, fun to drive, but still ............ what's it worth vs just buying a newer Z28 ? All depends on how much work you can do yourself, and what end result you're looking for. Hope you build the car of your dreams !

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Old Dec 4, 2024 | 04:36 PM
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Re: Iroc 5.7 vs ls


im 10k deep an haven't started the engine yet . lm7 stock bottom end summit stage 2 turbo . trick flow .650 springs ls7 lifters . plastic intake off ebay . gt45 turbo . rebuilding my 700r4 that came in the iroc originally
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