Is a stock 4.8 enough for a K5?

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03-13-2009, 05:23 PM
Oilbrnr

Is a stock 4.8 enough for a K5?

So I have a complete 2007 4.8 truck motor, harness, and PCM. Destination would be a '77 K5 with a SM465/205 that I want to keep.

Will this engine be enough to use as a daily driver until I can either build up a 5.3 or 6.0? I'm running 33's with original gears. Seems like the 4.8 and the old Goodwrench 350 crates are rated about the same hp/lbs., though I know ft/lbs in low RPM situations might be dramatically different...

I figure much of the conversion costs will be fixed anyway regardless of which motor I go with; flywheel, clutch, fuel, wiring, etc., etc.

Thanks for any input.
03-13-2009, 08:15 PM
AceX

I'm working on a conversion right now to put a 6.2L in an '85.

There's ALOT involved that you really never think about until you talk to someone who's done it, and worse yet, have to make it pass CARB emissions...

The guys @ Speartech and S&P have been unbelievably helpful in figuring things out.

Street and Performance (S&P) can get you everything you need and have real world experience doing this stuff.

Just for you: 77chevy
03-13-2009, 08:32 PM
George C

4.8s rock!!!!
03-13-2009, 09:32 PM
LEEVON

cam it and call it a day
03-14-2009, 12:10 AM
AceX

The 4.8 will eat boost like a fat chick eats cupcakes.
03-14-2009, 12:49 AM
99sierra4x4

i would say that the 4.8L will more than surprise you. probably has more power than the stock engine that came with that truck.

My dad had one with a manual in it when i was a kid that thing rocked.
03-14-2009, 07:36 AM
GasGuzzler

My 4.3 has more power than the stock 350 that came in it and that says nothing.
03-16-2009, 03:08 PM
Oilbrnr

Quote:

Originally Posted by GasGuzzler

My 4.3 has more power than the stock 350 that came in it and that says nothing.

Nothing or something?
03-16-2009, 03:13 PM
Oilbrnr

Luckily I'm in AZ so emissions is tied to the year of the chassis not to the engine. So for a '77 I only have to pass CO and NOX sniff test. No other devices are required.

Someone above mentioned putting in a new cam and calling it quits. Is there an off the shelf cam that would be good for this application?

Thanks again for the info guys!
03-16-2009, 07:58 PM
AceX

I would get the motor to pass emissions first and foremost and see what kind of room you have to play with. If you have tons of room, then do whatever you want, but it you don't, then try a lighter touch.
03-16-2009, 09:24 PM
GasGuzzler

Quote:

Originally Posted by Oilbrnr

Nothing or something?

Nothing. You won't be happy with a stock 4.8. If so, save some money and put in a 4.3. They're cheaper and lighter and almost the same power stock.
03-16-2009, 09:26 PM
George C

Quote:

Originally Posted by GasGuzzler

Nothing. You won't be happy with a stock 4.8. If so, save some money and put in a 4.3. They're cheaper and lighter and almost the same power stock.

confused :confused: 180hp/240tq vs 275hp/285tq
03-16-2009, 09:31 PM
GasGuzzler

Stock 4.8 with 275 HP :LOL:

40 TQ isn't much difference for another 150 pounds.
03-16-2009, 09:46 PM
SLO TRUCK

A good cheap cam would be a used ls6 cam and wont need at stall. should be able to find one for around 150.00. I think the 4.8 will do good in there.
03-16-2009, 09:51 PM
GasGuzzler

Sure will...as long as it gets some help before getting stabbed in there.
03-17-2009, 04:25 PM
Oilbrnr

Quote:

Originally Posted by Quik

confused :confused: 180hp/240tq vs 275hp/285tq

I'm confused too! Again, for right now, I'm happy with power similar to the original 350. She is tired and due for a refresh. I just figured since I already have the 4.8, it is a sunk cost. Get it in and running, then look for a 5.3 or 6.x in the mean time.
03-17-2009, 04:26 PM
Oilbrnr

Quote:

Originally Posted by murdered_outgmc

A good cheap cam would be a used ls6 cam and wont need at stall. should be able to find one for around 150.00. I think the 4.8 will do good in there.

Can the lifters be re-used too, or is that a no-no.
03-17-2009, 04:28 PM
Oilbrnr

Quote:

Originally Posted by GasGuzzler

Nothing. You won't be happy with a stock 4.8. If so, save some money and put in a 4.3. They're cheaper and lighter and almost the same power stock.

4.3? In a K5?
03-17-2009, 05:59 PM
George C

Quote:

Originally Posted by Oilbrnr

I'm confused too! Again, for right now, I'm happy with power similar to the original 350. She is tired and due for a refresh. I just figured since I already have the 4.8, it is a sunk cost. Get it in and running, then look for a 5.3 or 6.x in the mean time.

if you have the 4.8 use it. it will do as you want. a 4.8 is rated for 275/285 which is plenty enough power compared to the older motors of 190hp 350s
03-17-2009, 06:34 PM
WARLOCK

Yeah what quik said. But I would drop a cam in it too. Never hurts to have more power.
03-17-2009, 09:27 PM
6.0vortecchevy

I rather put a 350 in the instead of a 4.8, I rather have low end torque power. especially if you have bigger tires and want to mud it, a 4.8 would be stupid to put in there.
03-17-2009, 10:52 PM
GasGuzzler

But a stock 4.8 will never make near the rated power in a vehicle hence my comments. Stock to stock at the wheels it's almost the same...too far over so many heads. Nevermind. Put a cam and long tubes with a tune at least.