Engine builders - need your help here

[Lengeo]

In the April issue of Car Craft (Yes, April 2007) they take a junkyard Gen3 6.0L (364 CI) truck engine, added a GMPP carb manifold with a 750 Holley, mild GMPP cam, MSD ignition and long tube headers.

 

The end result was 480 HP and 450 ft-lbf for $3775.

 

I've been looking at the Gen3 LS1 engines but have found them to be somewhat expensive and often abused.

 

The Vortec 5300 (LM7) is a V8 truck engine (5.3L 323 CI.) based on the Gen3 small-block V8. The LM7 is a very common junkyard motor so it is much less expensive than the LS1.

 

Using the concept from the Car Craft article I came up with this engine idea:

 

$540 Vortec 5.3L (323 CI) LM7 Engine, low milage junk yard unit

$690 Edelbrock Performer LS1 Intake Manifold Kit with MSD ignition

$266 Edelbrock Performer 600 cfm 4-Barrel carb

$300 Edelbrock Performer RPM Hydraulic Roller Camshaft

$250 Crane Valve Springs, retainers and cups

$370 Hooker Super Competition Block Hugger Headers

$ 84 Gaskets, Oil, filter

 

$2500 total

 

A similar setup on a 5.7L block with an 800 cfm carb pulled 410 HP.

 

Does this sound like a good swap engine for my street driven 280Z?

 

Thanks for any help!

Lenn

[Pete84]

Correct me if I'm wrong, but the way I read that article the dyno was at the crank, so 2/3's for rwhp.

 

I've also read that the high-rise intake on the truck motors flows rather well, what is keeping anyone from using the stock EFI setup? Just swap on a LS1/6 intake for clearance on zcars and you can save on stand alone ignition and carbs.

[280zwitha383]

That is true, swap in the cam with optional springs etc., you will probably end up putting headers on it anyway and you will have a pretty stout little setup. Cheap too.

[LS1 240Z]

a few things... buy a 6.0, its a much much better motor, and if you arent wanting to do a head swap, buy an LQ9, they are more expensive but they are high compression. as for camshafts, if you are going through the trouble of swaping a cam, it should be for a huge cam.

 

buy an LQ9, put the carbed intake on it and leave the rest alone.

 

also, dont waste time on "blockhugger" headers, the 00+ f body and truck manfolds flow just as well.

 

if you did a cam swap ($400 cam, $40 timing chain, $160 oil pump, $250 springs) rod bolts ($165) carbed intake and headers you could be looking at well over 500 crank hp. there are just so many cheap head, cam options its literaly endless.

[Pete84]

What is the advantage to going to a carb? The EFI can be tuned, can't it?

[LS1 240Z]

yes, efi is better, but it also requires a wiring harness, computer and injectors. most junkyard motors have their wiring harnesses hacked. it simplifies the install quite a bit also. it just comes down to personal prefrence, im keeping the injection

[Lengeo]

dont waste time on "blockhugger" headers, the 00+ f body and truck manfolds flow just as well.

 

Do the stock manifolds work with the JCI mounts and 280Z steering?

[Lengeo]

buy an LQ9, put the carbed intake on it and leave the rest alone.

 

The way I see it an LQ9 6.0L (10.08 comp ratio) would be $2000-3000, plus intake and carb, puts that combo at $2950 to $3950.

 

My suggested LM7 5.3L (9.49 comp ratio) without the block huggers is now $2130.

 

Remember this is street driven and I'm more interested in the looks and sound of a carbed motor with added cam while keeping the cost reasonable.

[dr_hunt]

Remember this is street driven and I'm more interested in the looks and sound of a carbed motor with added cam while keeping the cost reasonable.

 

 

That desire will be quickly replaced with "THE NEED FOR SPEED"! Warning the surgeon general has determined that going fast may be addictive. Special treatment programs haven't shown any decrease in addiction tendencies. Side effects may include being broke, unusual dreams, loss of sleep, extended nights in the garage wrenching and uncontrolled buying of hotrod parts from Summit, Jegs and EBAY! May result in the loss of wife/girlfriend. In the case an erection lasts longer than 4 hours, stop and gas up, you'll find a new exwife/exgirlfriend.

[rytherwr]

You're a sick man, Doc!!!! )

 

Wayne

[Guest Mike]

That desire will be quickly replaced with "THE NEED FOR SPEED"! Warning the surgeon general has determined that going fast may be addictive. Special treatment programs haven't shown any decrease in addiction tendencies. Side effects may include being broke, unusual dreams, loss of sleep, extended nights in the garage wrenching and uncontrolled buying of hotrod parts from Summit, Jegs and EBAY! May result in the loss of wife/girlfriend. In the case an erection lasts longer than 4 hours, stop and gas up, you'll find a new exwife/exgirlfriend.

 

DOC... Get real. If your erection won't die for 4 hours you're NOT losing any wife or GF.

[LS1 240Z]

The way I see it an LQ9 6.0L (10.08 comp ratio) would be $2000-3000, plus intake and carb, puts that combo at $2950 to $3950.

 

My suggested LM7 5.3L (9.49 comp ratio) without the block huggers is now $2130.

 

Remember this is street driven and I'm more interested in the looks and sound of a carbed motor with added cam while keeping the cost reasonable.

 

LQ9 without the accessories and wiring harness wont be over $1500

[73ZCAR]

Yup,

 

I just looked at them on http://www.car-part.com.

 

There are a couple of them for between $1500-2K.

 

Anybody know how these motors compare weight wise to an early small block w/ aluminum heads?

 

Mike.

[Ledphoot]

That desire will be quickly replaced with "THE NEED FOR SPEED"! Warning the surgeon general has determined that going fast may be addictive. Special treatment programs haven't shown any decrease in addiction tendencies. Side effects may include being broke, unusual dreams, loss of sleep, extended nights in the garage wrenching and uncontrolled buying of hotrod parts from Summit, Jegs and EBAY! May result in the loss of wife/girlfriend. In the case an erection lasts longer than 4 hours, stop and gas up, you'll find a new exwife/exgirlfriend.

 

I CAN SOOOOO RELATE TO THAT STATEMENT!!!!! Since I hurt my back in July I spend all of my time on all of the afore mentioned sites and then some!!!

 

I can't tell you how many builds I've done and shortly after wish I had held out for a little more power... dont let 500-800 bucks stand between you and something you'll truly enjoy unless your really on a tight budget. But 2100 compared to 2800 shouldnt be more than a few weeks of savings. Just start skipping meals,shower less,sit in the dark,stay home and save up!!!! LOL!!!

[Guest Mike]

Yeah... I decided take a BIG leap instead of a small one. My SBC 350 w/ ~350/350 FWHP/TQ just isn't enough. I'm going for more cubes and at least 700/700 this time;)

[Pop N Wood]

There are a few other expenses that are being forgotten.

 

The "00+ f body and truck manifolds" may flow as well, but they won't fit in a Z. So keep that $400 budgeted for headers. You should be able to use the JTR headers.

 

Also you will need an F body oil pan since the truck pan is too deep. That will probably mean a new oil pickup and possibly windage tray. Good luck finding that stuff at a junk yard, so hello GM direct for new parts.

 

Then the truck accessories (including the water pump) are different from the F body stuff (which is different from the Corvette stuff). If all you want is an alternator then you might be able to work up a custom mount. Otherwise you are looking at getting an F body water pump, crank pulley, and brackets. Not sure if the alternator is the same between the truck and F body. Once again that stuff isn't exactly littering the JY's so you may need to ebay or buy new.

 

Last the reason you can't use the truck FI is I believe it will be too tall to fit under a Z hood. The carb intake is pretty tall also and may not clear a stock hood when using the JCI mounting kit. Custom mounts will allow you to get the engine lower. But then you are building custom mounts.

[jonus079]

Yup,

 

I just looked at them on http://www.car-part.com.

 

There are a couple of them for between $1500-2K.

 

Anybody know how these motors compare weight wise to an early small block w/ aluminum heads?

 

Mike.

 

i just baught a 5.3l lm7 for $300 with 50k on its (confirmed) the 6.0 will cost more though.

 

i know for a fact the lm7's block is 109 pounds more than the ls1. over all i cant see the engine being more than 120 pounds over the ls1. they both use the same crankshaft and same rods.

[jonus079]

There are a few other expenses that are being forgotten.

 

The "00+ f body and truck manifolds" may flow as well, but they won't fit in a Z. So keep that $400 budgeted for headers. You should be able to use the JTR headers.

 

Also you will need an F body oil pan since the truck pan is too deep. That will probably mean a new oil pickup and possibly windage tray. Good luck finding that stuff at a junk yard, so hello GM direct for new parts.

 

Then the truck accessories (including the water pump) are different from the F body stuff (which is different from the Corvette stuff). If all you want is an alternator then you might be able to work up a custom mount. Otherwise you are looking at getting an F body water pump, crank pulley, and brackets. Not sure if the alternator is the same between the truck and F body. Once again that stuff isn't exactly littering the JY's so you may need to ebay or buy new.

 

Last the reason you can't use the truck FI is I believe it will be too tall to fit under a Z hood. The carb intake is pretty tall also and may not clear a stock hood when using the JCI mounting kit. Custom mounts will allow you to get the engine lower. But then you are building custom mounts.

 

you wana bet i cant fit that intake under my hood? the oil pan is very easy to find on ebay or you can modify yours. another thing is alot of people like the deaper oil pans (if they can fit it in thier car), you can sell you deaper oil pan for $100 easy on ebay.

 

the alternator is mounted alittle higher when compared to the corvette alt which is lower and further left. you shouldnt have any problems there.