5.3 ls motor potential
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custom442 said:
No. I bought my truck the year before they changed over to the 6 speed. I believe mine is the 4L60E trans as all of the 1500 trucks got this transmission unless you had a 6.0/6.2L which believe got the bigger 4L80E at that time.
and lets look at many stock 350's. late 80's camaro=225hp IIRC hell the "high performance" ones produced an earthshaking 300hp!
yes the LS used to cost 3k to put in, when no one made parts for it, a new day has dawned! it's a lot cheaper now and there are plenty of junkyards to get the wiring harness.
the fuel pump is relatively cheap/standard, and if you get the MK4 GM "aftermarket" ECU it's fully programmable and works with the LS system. or you could go with megasquirt.
yes the LS used to cost 3k to put in, when no one made parts for it, a new day has dawned! it's a lot cheaper now and there are plenty of junkyards to get the wiring harness.
the fuel pump is relatively cheap/standard, and if you get the MK4 GM "aftermarket" ECU it's fully programmable and works with the LS system. or you could go with megasquirt.
custom442 said:
I've heard mixed reviews about the 6 speeds. Some like them and others say they feel like the transmission is constantly hunting for another gear.
I wish they would offer 6 speed manuals in the full size gas trucks. :?
FE3X CLONE said:
Ya they did away with the 5 speed a while back in the 5.3's scsb. Then in the 4.8's - which is what I wanted it wouldve been an awesome combo. So I settled for a 4.3 5 speed. The transmission mattered more to me than the engine. A truck with a little power and a manual is sooo fun in an empty parking lot :lol: My friend has a 6spd 5.3 it's pretty high tech stuff. He gets 19mpg going from here to stillwater OK but that thing is like 5500lbs.
you could do a t56 swap I was sooo close to doing one and then changed my mind. Had found one for 900$ with everything. Would be much easier to do if it's already a manual truck. Problem is you'd have to find one with a .50 final gear, because you'd need at least a 4.30-4.56 for it to 'feel' stock. To get going as fast as say an nv3500 in 1st/2nd with 3.73/4.10 youd need somewhere around 5.10-5.33. Then the .50 overdrive isn't as appealing. Theres some t5's out there that have more ideal gearing and then the s10 nv3500.
custom442 said:
The truck mileage is unimpressive.
My '89 C1500 with a TBI 350/700-R4 averaged 18-20 mpg, and that thing had over 200K miles on it.
However, when those motors kick out 30 mpg in a car with all that power to boot is awesome.
Blake442 said:
True but I doubt your '89 350 has the same power the new trucks have.
I tend to average around 17.5-19.5mph combined city/highway with my extended cab. The 4 cylinder mode on these trucks I've found doesn't really do much of anything. Maybe .5-1.0mpg better than not having it. My tuner removed the 4 cylinder mode from my truck and it makes it much more lively.
ever heard of yates efi? they built a 62 nova with stock 5.3 with ls6 cam and intake with BW75mm turbo. very cheap build, i know less than five g's, ran low tens on an open rear end on 15psi. he said it ran perfect on 15psi stock block no problems at all. 18psi is when it grenaded. it made around 500 whp. yeah a truck may be slow with a 5.3 but thats like what, 4500 pounds? g bodys are over a thousand pounds less, they will not run the same as they would in the truck for the simple weight factor. and 6.0's are not $200 more than a 5.3 that i seen earlier on this post, as far as i seen. their about between $400 more and double the price of a 5.3. i will say, i do think it is a waste to build a N/A 5.3 if you wanna go fast in my opinion. you need more cubes. just what i think.
Blake442 said:
the mileage hasn't gone up much (that mpg was in a 5800 lb crew cab), but the trucks can do things now that could've never been possible in the old tbi's. Cabin safety I guess is better, these trucks are so heavy compared to your model because all the extra safety crap. It's the entire drivetrain not so much the engines, there's 5.3 1500's now with 10,000 lb tow rating.. to even have that safely from the factory with 18-19mpg is pretty impressive
to get 30mpg out of this would need a t56 with a .50 overdrive, which is another 1500-2000$+. By my best guess it would see 25-26 mpg on the hwy. It isn't the weight of the vehicle as much as where the engines sit in their torque curve on the highway and the gearing... and aerodynamics. For example a 3.73 with 4l60e/5.3 isn't going to return 12 highway mpg just by taking 1500-2000lbs off, nor are our stupid flat rear windows much more aerodynamic than a small truck. With our 2.14's it could see 26-28mpg, but they don't have enough torque to justify the mileage... if doing that why not add some go fast parts to the existing 307/305 and make 300 torque the 'seat of the pants' feel would be the same. Or make a small block cammed and geared for mileage, return 20mpg and make 50+ more torque than a stock 5.3.... or buy an ls1 or 6.0.
I know ...everyone hates me in this thread
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