Real world Engine opinions, sbc vs ls swap

[Z10]

Ok, I'll be the contrarian to the LS argument. Yes they are cheap and plentiful, but they sure are ugly. I took another route. FIRST TPI fuel injection on top of a ZZ4 making about 375hp and 420ft.lbs of torque, mated to a 700r4 trans, power steering, A/C, power (soon to be 4wheel disc brakes), OEM cruise control, etc.
And it's currently returning about 17mpg on the highway.

[Fitz]

Originally Posted by sixtyeightC10

Even for a truck?

The GM Historical center lists only one 327 engine available as an option in a C series in 1968...the L30. That engine was de-tuned for truck applications and was rated at 245 HP @ 4400 rpm. Check your SPID. If your truck is equipped as your tag line says: 1968 C10, 327 large journal crank, TH400 trans, 12 bolt 3.73 geared rear axle there is something wrong. The 3 speed TH trans option available for the 327 equipped trucks was M49 and was only available with a 3.07 rear axle ratio.

I would say that if your truck is equipped as you say, it has been modified by a previous owner.

[greengrenade]

I do agree on the looks of the ls, there not pretty at all. But in my eyes, a small block chevy with a 3x2 setup is gorgeous, i have yet to see a modern fuel injected engine come close to a clean vintage motor as far as looks. Too much **** to hide imho. So as far as that goes ive accepted that the engine isnt gonna be as good looking as a traditional sbc. Ill save the good looking motor for a traditional 30-31 model a coupe id like to build some day. The lq9 looks very promising. The guy next door to me just picked up a lq4 recently with a 4l60e, i didnt know wtf an lq4 or lq9 was like two weeks ago when he told me lol but he got the motor n trans combo for 3300 bucks, had 27,000 miles on it out of a wrecked van

[Nitis]

Dads 3 deuces in his 72 gmc. He said that's what all the cool kids had in their cars back in the day.

[Z10]

Originally Posted by Nitis

Dads 3 deuces in his 72 gmc. He said that's what all the cool kids had in their cars back in the day.

Nice!

[sixtyeightC10]

Originally Posted by Nitis

Dads 3 deuces in his 72 gmc. He said that's what all the cool kids had in their cars back in the day.

Very nice!

[ahsom79vette]

Holley Performance makes some stuff that makes the LS look more 'traditional'. In fact I think they have many products for swapping the LS into these trucks.

Their shop truck is pretty nice setup with an Aluminum LS3 w/ T56 6-speed, and 500 rwhp. Was looking at pics of this truck a while back, and looks like they did a really nice job in keeping with the nostalgia and combining the modern drive-train and performance.

Jay Leno actually just did an episode with this truck. I don't think they mentioned the actual mpg's, but said that it did really well. Holley put on their coil pack/ valve covers, which helps hide the un-sightly.

I would guess from what you guys have said that this is probably a fairly pricy $$$ setup, though.

[sixtyeightC10]

Originally Posted by Fitz

The GM Historical center lists only one 327 engine available as an option in a C series in 1968...the L30. That engine was de-tuned for truck applications and was rated at 245 HP @ 4400 rpm. Check your SPID. If your truck is equipped as your tag line says: 1968 C10, 327 large journal crank, TH400 trans, 12 bolt 3.73 geared rear axle there is something wrong. The 3 speed TH trans option available for the 327 equipped trucks was M49 and was only available with a 3.07 rear axle ratio.

I would say that if your truck is equipped as you say, it has been modified by a previous owner.

Thanks for the reply. I'll start digging through my stuff and see where I have buried all of my info. I'm now curious to see if it is all original or has been gone through, like you said, with said items.

[truckdude239]

i went lsx for one reason my 305 that i had built after sittign for like a year it broke 2 push rods and wiped the cam from a stuck vavle, i was looking at almost 900 dollars for reworked heads cam, lifters and push roods plus labor, i got a 4.8 and 4l60e harness computer all accessories but the ac compressor for 1100 with 150k on it, 400 buxs to mod the harness and flash the computer but now it starts every time where the carbed 305 didn;t

[greengrenade]

Ive been doing a lot more research on prices and theres a tonnnn of engine for sale on ebay and the like with certified compression tests and other gauranteed tests done as well as running videos etc. i even checked out some ls3's but there pricey, on the contrary the ls2 or an lq9 are cheaper but harder to find a decent mileage engine. Ive found t56's for 900 to 1400 really consistently. I have a fresh rebuilt muncie in the truck now, im hoping i can get a good price for that and pay for most if not all the price of the t56. Ill probably just end up with whatever engine/harness combo i can get a good deAl on when the time comes

[greengrenade]

Also i was on the vette forum and pretty much everybody is able to milk at least 27-30 on the highway with both the ls2 and ls3. Granted the vette has aerodynamics like a spear, and my truck is built like a cruise liner in comparison. But if i can keep the weight reasonable(which should be fairly close to a vette at 3200-3300 lbs) i think scraping the 25 mpg mark might be doable on the highway

[Z10]

Originally Posted by greengrenade

Also i was on the vette forum and pretty much everybody is able to milk at least 27-30 on the highway with both the ls2 and ls3. Granted the vette has aerodynamics like a spear, and my truck is built like a cruise liner in comparison. But if i can keep the weight reasonable(which should be fairly close to a bette at 3200-3300 lbs) i think scraping the 25 mpg mark might be doable on the highway

I think you are way optimistic on getting 25 out of LS/c10 combo. Check with new truck owners and you'll get numbers from 14 to 18. Now the c10 is lighter so, maybe 20.

[Lee H]

I did not read all the posts but here goes. I've done 3 383s now. To get get magical numbers and still be daily drivable I've had to spend about 6k carb top pan, water pump to fly wheel. My best, the current one, is right at 360 HP & 400 torque at the rear wheels, and it barely has enough vacuum to work the brakes. With EFI add about 2k conservatively, trans to handle the power about 2k. Hind sight being 20/20 I would have gone LS complete pull out, harness, trans to handle the power, FI, all accessories, simple cam swap and more power & drive-ability for way less than half the cost. Another 1k for swap stuff and your golden. Don't expect better mileage, just a great power plant in an old iron work horse. I'm getting near 13 miles to gallon around town, about the same as my max Silverado.

[ahsom79vette]

Just watched another video that a member here referenced, on the Holley shop truck.

They were getting ~20mpg with that LS3/T56 combo. If an LS swap could return even in the low 20's mpg, I think that's fairly impressive.

My stock 402/400 gets an incredible ~7mpg. I'd be ecstatic with 20, but don't think that would happen with a C20.

[greengrenade]

I have a 55 stepside, i realized i posted in the 67-72 section after i started this thread. Ive read online that some of the 67-72's can weigh in as much as 4200 lbs but average out around 3900ish. The 55's are supposed to be around 3200 lbs, if i can keep that number somewhat close to that i think that would help in the mpg department. Again even at that weight 25 is stretchin it, but just to be anywhere close to that would be awesome. My little beater ford ranger parts hauler gets around 18 and has about 160 horse. Id be ecstatic with anything over 20 and 400 horse

[greengrenade]

Originally Posted by Z10

I think you are way optimistic on getting 25 out of LS/c10 combo. Check with new truck owners and you'll get numbers from 14 to 18. Now the c10 is lighter so, maybe 20.

The lightest curb weight i could find for say a 2009 silverado was right around 4700 lbs. and that was a reg cab short bed base model with no options. Ur typical pickup that everyone drives nowadays, the ext cab short bed, weighed in At 5150 lbs, again without options. Weight isnt everything, but shaving over 1,500 lbs compared to my 55 is a lot of weight. Id expect mine to be in the 3450 range honestly. I think tuned properly 22 ish is doable, ill aim for the 25 mark but as i said anything over 20 with 400 horse would be killer

[streetstar]

Originally Posted by greengrenade

I believe the truck version 6.0 came in at around 330 horse or something similar?? Id assume i could swap parts around and bump the power considerably on that engine to get it back around 400hp, ill have to research more tho. anyways

I have an 07 6.0 and i believe it is factory rated at 360 or 365. --granted, not an earth shattering difference over 330, but with the factory 6 speed auto, it can haul the mail for a crew cab 3/4 ton
I have been looking for one off and on for my project---- im not a serious go faster, so the stock 6.0 would be fine for me in the much ighter c10

[greengrenade]

^^ yea ur right the newer ones are around 360 ish hp. The engines i was lookin at outta the trucks are the earlier lq9's. I think the truck engines after the lq9 (which i believe the lq9 ended in like 05 or 06) have some type of active fuel system in them or something. The truck motors all look like solid options, and i agree, i dont want to get much more power than what they offer stock. But a cam swap and some other factory heads i can find on a budget wouldnt hurt lol

[BigDaddyV]

Im a hard core old school guy my self, but I have to throw this pic of 67Cheby's Square peg motor, You can make a LS motor look good....

But I love my 1970 Corvette 350

[Fitz]

Originally Posted by BigDaddyV

Im a hard core old school guy my self, but I have to throw this pic of 67Cheby's Square peg motor, You can make a LS motor look good....

But I love my 1970 Corvette 350

OOOHHH Eye Candy!

[Andy4639]

Why not use a LS motor and make it look old school. It's been done and farely cheap also.

[greengrenade]

Its funny you guys posted those pics. The first thing i looked for was either a coil relocation or coil cover. Those look really cool. I only found one other one where a guy took a 235 gmc i6 cover and cut it down and custom built a "valve cover " for each side of the engine. Those look cool as hell guys

[Andy4639]

I had a cover made locally for my 6.0 and pick it up tomorrow to do final fitting and then prep work to have it painted. It will bolt down just like the orignal cover and cover both sides of the coils.