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Author Topic: Simple question about 5.3 vs 5.7  (Read 9536 times)

Offline largeorangefont

Re: Simple question about 5.3 vs 5.7
« Reply #15 on: May 22, 2014, 01:06:33 PM »

In my experience, and it costs the same when its all said and done.... and in the end you end up with a heavy, low compression engine, smaller displacement engine.  Id on't think there's $1000 to be saved.  Now that being said, this was a car that retained the stock hoodline which meant no truck intake sticking out the hood, which I believe is what 99% of swappers want judging by the one or two guys total on this forum that actually use a truck intake.  If you say there's money to be saved by waiting around for deals, you'd have to also say that you could probably find a good deal on a full LS1/T56 pullout if you had time to wait for a deal. 

In my opinion the real best way to save some money buying a LS1/T56 is to buy a full donor car, snag the engine and trans for yourself and part out the rest.

Agreed, buying a donor car is most cost effective, but is the most legwork and effort.

All aluminium 5.3s, even L33s, are getting pretty cheap. They can be had for around $1000 easily, cheaper if you are patient. You can get an LS1 intake fuel rail and injectors for $100 bucks. Then you need a Fbody pan, that's another $200. Call it $1300 for your 300 hp engine... That's pretty good. Call it another $2000 for a used flywheel, clutch, and T56, and another $500 for ECU and harness. You are at $3k after a couple other odd and ends, and ready to go.

It comes down to the price of the pullout..
This one is a LS1/T56 pullout with all wiring, emission equipment, fuel tank, driveshaft etc for $4k. Is the extra cash worth it? That is a case by case basis.
http://www.ebay.com/itm/151301537936

There are other ls1/t56 pullouts up to $5500 so it just depends on the cost. I have not seen many ls1/t56 pullouts for near $3k for awhile, but I'm not looking as often as I used to.

I got my LS1 (with known rod knock) and 4L60e with Fbody ECU and harness for $1000 about 5 years ago. I sold the trans for $300, rebuilt the engine the way I wanted it and bought a built T56. I had about $6k into the engine and trans, but they were 0 mile.


« Last Edit: May 22, 2014, 01:31:00 PM by largeorangefont »
Quote from: cool
Sell it to spacevomit.  He'll finish it.

Offline atli126

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Re: Simple question about 5.3 vs 5.7
« Reply #16 on: May 22, 2014, 01:19:24 PM »
if i was to do it all over, i would save up for a full ls1/t56 combo, but i pieced mine together over time with cash and boy did it hurt.... 50,100 at a time sucks  :banghead:

my 5.3 was 500 5 years ago with 80k but i made half back selling all the stuff off of it
-Bret
87 RX7 5.3/t56 TII Check it out >>>>http://www.502streetscene.net/forum/showthread.php?t=181938&page=4

"no one ever said it would be cheap and easy, they just said it would be worth it"

"Whatever you do, don't lose your passion. Without it who are you?" -Me

Offline largeorangefont

Re: Simple question about 5.3 vs 5.7
« Reply #17 on: May 22, 2014, 01:23:30 PM »
if i was to do it all over, i would save up for a full ls1/t56 combo, but i pieced mine together over time with cash and boy did it hurt.... 50,100 at a time sucks  :banghead:

my 5.3 was 500 5 years ago with 80k but i made half back selling all the stuff off of it


Yes, speed and simplicity is worth something for sure.
Quote from: cool
Sell it to spacevomit.  He'll finish it.

Offline mattster03

Re: Simple question about 5.3 vs 5.7
« Reply #18 on: May 22, 2014, 01:24:48 PM »
I do agree that L33's are worth it... aluminum block, higher compression and 799 heads you can make a case for that.  It's the steel 5.3's that I personally are becomming a bad trend in the swap community that are being fueled by bad information about them being the "cheaper" alternative to shelling out $4000-$4500 for an LS1/T56 pullout.  Here's a list of the parts with approximate I encountered when doing a 5.3L swap:

T56 trans with Clutch, pressure plate, flywheel, necessary hardware: $2000
Hydraulic TO bearing: $150
Starter (most truck pullouts don't come with them): $100
Fbody 6-speed Harness & 0411 PCM: $400
Fbody LS1 Intake Manifold w/injectors, TB, Sensors & bolts: $180
Fbody LS1 Oil Pan, Pickup, windage tray, gasket and bolts: $250
Fbody LS1 Water Pump: $100
Fbody LS1 Power Steering Pump: $150
Fbody LS1 crank pulley: $50
Fbody LS1 Tensioner: $50
Fbody Alternator Bracket: $30

PCM tuning (If you're running a 5.3L on a 0411 PCM, you need it): $400

I think these are pretty fair numbers for the "average" guy to piece together an LM7/T56 combo that will fit and run properly in an RX7.  The total cost is about $3800.  If an LS1/T56 complete pullout is $4000-$4500 on average, that makes the cost of the LM7 from the junkyard to be $200-$700 to be the exact same cost... and IMO that's about the national range of what they cost.  This is all just to show that in the end you spend just as much...

« Last Edit: May 22, 2014, 04:10:10 PM by mattster03 »
Current Car: 1993 Mazda RX7 Touring, LS1/T56, Stock Stock Stock

1993 Mazda RX7 R1, LS1/T56, EPS 230/238, TSP Ported heads
10.826 @ 128 , 1.53 60' - SOLD

Feature Article - http://www.importmeet.com/blog/2012/03/29/best-of-both-worlds-v8rx7guys-ls1-swapped-1993-mazda-rx-7/
Swap Info - http://www.cardomain.com/ride/2801662

1986 Mazda RX7 GXL, LT1/T56 "Retired"
Swap Info - http://www.cardomain.com/ride/641869

Offline mattster03

Re: Simple question about 5.3 vs 5.7
« Reply #19 on: May 22, 2014, 01:30:36 PM »
my 5.3 was 500 5 years ago with 80k but i made half back selling all the stuff off of it

What did you sell off of it?  I can't even give any of the parts away that are in my shop from a 5.3L...
Current Car: 1993 Mazda RX7 Touring, LS1/T56, Stock Stock Stock

1993 Mazda RX7 R1, LS1/T56, EPS 230/238, TSP Ported heads
10.826 @ 128 , 1.53 60' - SOLD

Feature Article - http://www.importmeet.com/blog/2012/03/29/best-of-both-worlds-v8rx7guys-ls1-swapped-1993-mazda-rx-7/
Swap Info - http://www.cardomain.com/ride/2801662

1986 Mazda RX7 GXL, LT1/T56 "Retired"
Swap Info - http://www.cardomain.com/ride/641869

Offline largeorangefont

Re: Simple question about 5.3 vs 5.7
« Reply #20 on: May 22, 2014, 01:34:23 PM »
Agreed Matt. At those prices it makes no sense. If you are willing to search for those parts you can shave hundreds off that price list, and that is where the savings lies.

Your prices are the general averages of what I could get the parts for today with no "bargain hunting"
Quote from: cool
Sell it to spacevomit.  He'll finish it.

Offline mattster03

Re: Simple question about 5.3 vs 5.7
« Reply #21 on: May 22, 2014, 01:42:23 PM »
The problem is that you're competing for the same parts with the other guys who are tying to get the exactly same parts because they're trying to do the same thing... the prices are now inflated and continuing to go up.  I remember when we all just threw away LS1 intakes because they were worthless, but now just the plastic is worth $100 shipped... that's because so many guys are going the iron block junkyard route and just need to get their engine running.

It's easy to say something like "oil pan: $200" but if when you've actually done a conversion you realize that you also need the pickup, windage tray, bolts, plug & gasket...  then you have to have that puppy shipped to you.  You just don't piece that together for $200... it works on paper until you actually try to buy the parts.
« Last Edit: May 22, 2014, 04:12:22 PM by mattster03 »
Current Car: 1993 Mazda RX7 Touring, LS1/T56, Stock Stock Stock

1993 Mazda RX7 R1, LS1/T56, EPS 230/238, TSP Ported heads
10.826 @ 128 , 1.53 60' - SOLD

Feature Article - http://www.importmeet.com/blog/2012/03/29/best-of-both-worlds-v8rx7guys-ls1-swapped-1993-mazda-rx-7/
Swap Info - http://www.cardomain.com/ride/2801662

1986 Mazda RX7 GXL, LT1/T56 "Retired"
Swap Info - http://www.cardomain.com/ride/641869

Offline digitalsolo

Re: Simple question about 5.3 vs 5.7
« Reply #22 on: May 22, 2014, 01:48:25 PM »
T56 trans with Clutch, pressure plate, flywheel, necessary hardware: $2000
Hydraulic TO bearing: $150 - Generally still needed with an LS1 swap...
Starter (most truck pullouts don't come with them): $100
Fbody 6-speed Harness & 0411 PCM: $400 - Not needed at all
Fbody LS1 Intake Manifold w/injectors, TB, Sensors & bolts: $180
Fbody LS1 Oil Pan, Pickup, windage tray, gasket and bolts: $250
Fbody LS1 Water Pump: $100
Fbody LS1 Power Steering Pump: $150
Fbody LS1 crank pulley: $50
Fbody LS1 Tensioner: $50

PCM tuning (If you're running a 5.3L on a 0411 PCM, you need it): $400  - Still needed with an LS1

That's $550 that's still needed for an LS1 and 400 that is not needed to be spent at all (that's a 4-5 hour job to modify the harness, or just use it as is, it's fine).   I'd also argue that any junkyard pull is going to have a starter with it, but even then, it's 25-30 bucks, so whatever on that I guess.

I generally see an LS1 pullout for ~2500 dollar range.    That puts a 5.3L about a grand cheaper than LS1, which is about what I see when I build these cars.   Whether or not a grand is worth it is up to you.
Blake MF'ing McBride
1988 Mazda RX7 - Turbo LS1/T56/ProEFI/8.8/Not Slow...   sold.
1965 Mustang Coupe - TT Coyote, TR6060, modern brakes/suspension...
2007 Aston Martin V8 Vantage - Gen V LT4/TR6060, upper/lower pullies, headers, tune.
2021 Tesla Model 3 Performance - Stock...ish.

Offline mattster03

Re: Simple question about 5.3 vs 5.7
« Reply #23 on: May 22, 2014, 01:48:55 PM »
It's just something I feel strongly about because I really am starting to see people dissapointed with their swaps because they just spent way more than they expected to get a truck motor in their car and now they have a low compression iron block with truck cam characteristics...

Obviously there is a time and a place for iron blocks, boosted setups, but those aren't exactly the same guys that are going for the shoestring budget swaps lol
Current Car: 1993 Mazda RX7 Touring, LS1/T56, Stock Stock Stock

1993 Mazda RX7 R1, LS1/T56, EPS 230/238, TSP Ported heads
10.826 @ 128 , 1.53 60' - SOLD

Feature Article - http://www.importmeet.com/blog/2012/03/29/best-of-both-worlds-v8rx7guys-ls1-swapped-1993-mazda-rx-7/
Swap Info - http://www.cardomain.com/ride/2801662

1986 Mazda RX7 GXL, LT1/T56 "Retired"
Swap Info - http://www.cardomain.com/ride/641869

Offline largeorangefont

Re: Simple question about 5.3 vs 5.7
« Reply #24 on: May 22, 2014, 02:04:09 PM »
It's just something I feel strongly about because I really am starting to see people dissapointed with their swaps because they just spent way more than they expected to get a truck motor in their car and now they have a low compression iron block with truck cam characteristics...

Obviously there is a time and a place for iron blocks, boosted setups, but those aren't exactly the same guys that are going for the shoestring budget swaps lol

Realistically for future upgrades and performance potential it is probably better to put in a iron 5.3 truck motor than a SBC, both of which are similar weight.


Quote from: cool
Sell it to spacevomit.  He'll finish it.

Offline digitalsolo

Re: Simple question about 5.3 vs 5.7
« Reply #25 on: May 22, 2014, 03:01:25 PM »
FWIW, my cam/heads 5.3 took down Azar's heads/cam 5.7 which had 399.8 RWHP.

The power difference from just over 20 ci and .5 or so points of compression isn't all that dramatic.   The stock cam in a 5.3 SUCKS hard though.    Cam/springs are a huge upgrade for those motors.

By the way, I'm not trying to be a huge 5.3 proponent or anything, just noting that if you pay attention to deals and put some work in, it's a very good option.   I have owned:

4x 5.7s (aluminum)
2x 5.3s (iron)
1x 6.0 (iron)

in the past few years...    I have an aluminum 5.7 right now and will probably put an aluminum 6.2 in at some point in the future if I have the car that long (or will use one in my next car).
« Last Edit: May 22, 2014, 03:14:34 PM by digitalsolo »
Blake MF'ing McBride
1988 Mazda RX7 - Turbo LS1/T56/ProEFI/8.8/Not Slow...   sold.
1965 Mustang Coupe - TT Coyote, TR6060, modern brakes/suspension...
2007 Aston Martin V8 Vantage - Gen V LT4/TR6060, upper/lower pullies, headers, tune.
2021 Tesla Model 3 Performance - Stock...ish.

Offline gc3

Re: Simple question about 5.3 vs 5.7
« Reply #26 on: May 22, 2014, 03:13:59 PM »
so i went the cheap deals here, good trades there method.
obviously im forgetting stuff here and there, but the deals are definitely out there, you just gotta find the right ones.

my 5.3 with all accessories and harness and starter and ecu.
it was either $300 or $400, i cant remember anymore, but even if it were $400, pretty cheap.
t56+bellhousing+flywheel+slave $1200.
used clutch $200
friend with tunercats = free pcm tune update to a 6speed.

truck pan straight trade for fbody oilpan
couple accessories off the front of the 5.3 for a couple accessories off the front of someone's fbody setup, straight trade
same with crank pulley.
longtube mustang headers + some waterjet flanges $150

I went the manual steering rack so no cost there.


All this for <$2000 if you know what deals you are looking for.
and it only took me 2 years to piece together everything.

so obviously this is hard to compare to a AC, power steering GT car, but for someone like me who came across an $800 rx7 to go racing with on the cheap, it's hard to beat 300 horses for $2k.

I just feel offended every time people say the 5.3 swap isnt worth it, because I would have a very hard time justifying spending a lot more money for saving what, 50-100 lbs and gaining maybe 50 horses.

Offline cool

Re: Simple question about 5.3 vs 5.7
« Reply #27 on: May 22, 2014, 03:24:25 PM »
It's just something I feel strongly about because I really am starting to see people dissapointed with their swaps because they just spent way more than they expected to get a truck motor in their car and now they have a low compression iron block with truck cam characteristics...

LS fever - Expecting a stock 5.3 to perform better than it did in the truck it came from.  People who are disappointed by this should have done more research instead of just snatching up a LS motor BECAUSE LS MOTOR! 

I agree with you about the price points.  If you plan to keep it stock, why not spend a little more and get more engine. However once you start modifying either engine, the initial price difference becomes null and the money you saved buying that 5.3 can go to parts. 

Offline mattster03

Re: Simple question about 5.3 vs 5.7
« Reply #28 on: May 22, 2014, 03:42:28 PM »
so i went the cheap deals here, good trades there method.
obviously im forgetting stuff here and there, but the deals are definitely out there, you just gotta find the right ones.

my 5.3 with all accessories and harness and starter and ecu.
it was either $300 or $400, i cant remember anymore, but even if it were $400, pretty cheap.
t56+bellhousing+flywheel+slave $1200.
used clutch $200
friend with tunercats = free pcm tune update to a 6speed.

truck pan straight trade for fbody oilpan
couple accessories off the front of the 5.3 for a couple accessories off the front of someone's fbody setup, straight trade
same with crank pulley.
longtube mustang headers + some waterjet flanges $150

I went the manual steering rack so no cost there.


All this for <$2000 if you know what deals you are looking for.
and it only took me 2 years to piece together everything.

so obviously this is hard to compare to a AC, power steering GT car, but for someone like me who came across an $800 rx7 to go racing with on the cheap, it's hard to beat 300 horses for $2k.

I just feel offended every time people say the 5.3 swap isnt worth it, because I would have a very hard time justifying spending a lot more money for saving what, 50-100 lbs and gaining maybe 50 horses.


I'm not saying it isn't worth it... any piston engine is going to be better than a rotary and with V8 power it's going to be fun.  I just am afraid that when people post up "why not just get an iron 5.3 from the junkyard it's sooo much cheaper" that people are actually going to believe that once they buy one they're just a few hundred more away from having it in the RX7.  I do realize there's deals to be made, but it's setting a false expection for future swappers that they are going to pick up a complete T56 for $1200 and they're going to be able to trade their truck pan for an FBody pan... and to keep the price low they have to run the intake out of their hood to make it fit.

I mean, if T56's are really $1200 then couldn't you just find a similar "deal" on an LS1 long block and run a truck complete manifold, harness, PCM on it and call it good for $2000 total?  If "deals are to be had" is the agument, you have to assume a good deal on an LS1 if you want to properly compare the two options and I'll still say it's a complete wash when the dust settles.
Current Car: 1993 Mazda RX7 Touring, LS1/T56, Stock Stock Stock

1993 Mazda RX7 R1, LS1/T56, EPS 230/238, TSP Ported heads
10.826 @ 128 , 1.53 60' - SOLD

Feature Article - http://www.importmeet.com/blog/2012/03/29/best-of-both-worlds-v8rx7guys-ls1-swapped-1993-mazda-rx-7/
Swap Info - http://www.cardomain.com/ride/2801662

1986 Mazda RX7 GXL, LT1/T56 "Retired"
Swap Info - http://www.cardomain.com/ride/641869

Offline digitalsolo

Re: Simple question about 5.3 vs 5.7
« Reply #29 on: May 22, 2014, 04:23:17 PM »
I can go build a 5.3L with more power than a stock LS1 for $500 less than an LS1, right now, with parts from the junkyard and crap on eBay.   It will fit under the hood and if I painted it silver no one would know it wasn't an LS1.

If $500 dollars doesn't matter to you (or 1000 if you don't mind having 30-40 less HP), then buying a 5.3L is really stupid.   I totally dig that.   I'd spend the $500 myself.   That doesn't make it stupid or a bad deal.

BTW, a bone stock 5.3L with some headers and a half-assed tune should run high 12s in the 1/4 mile with a T56, pretty damned easily.    That's not really the same as it in a truck.    300+ flywheel HP and 300+ torque in a 3000 lbs wrapper does not a slow car make.  I'm pretty sure all the guys with 302s and low model SBCs don't think their RX7s are boring.
Blake MF'ing McBride
1988 Mazda RX7 - Turbo LS1/T56/ProEFI/8.8/Not Slow...   sold.
1965 Mustang Coupe - TT Coyote, TR6060, modern brakes/suspension...
2007 Aston Martin V8 Vantage - Gen V LT4/TR6060, upper/lower pullies, headers, tune.
2021 Tesla Model 3 Performance - Stock...ish.