Discussion in 'Small Block Tech' started by JStov, Sep 21, 2019.
you will need a computer to run an LS setup
Or a some kind of ignition box. Even if carb swapped. No distributor provision.
I do a lot of LS swaps into chevy cars and trucks. They do cost $$$ to swap in and although they are good, leak free and reliable they normally don't give the greatest low RPM torque. The 4.8 and 5.3 are great for fuel mileage but lack any grunt on the low RPMs. The 6.0 make good power and torque but are hard on fuel. Long tube headers and a cam easily gain 80-100 HP on any LS engine but you need to do a custom computer tune to make it run right and that is more $.
The Buick 350 makes better low RPM torque than the 4.8 and 5.3, and better fuel mileage than a 6.0. For street driving the Buick 350 is a great option. Even with the 77 low compression engine you can make some serious gains without doing any work to the bottom end. Add a TA 212 cam, mill 50 thou off the heads, shorter pushrods, stock intake, Q jet with electric choke, headers, dual 2.5" exhaust, timing curve set to 14 degrees initial, 32 degrees total, plus 8 degrees of vacuum advance. It makes a big difference and for a lot less time and $ vs. a LS swap.
Or drive your car as is and find another Buick 350 to build up. About $2500 can build you a nice little Buick 350!
The new 6.6L crank out of the new 2020 HD2500 3.850 stroke will fix this low torque issue.
this crank in a 4.8/5.3 will be a 5.7L toque monster!
A little turbo fixes the torque issue too...
Turbo torque vs natural And instant muscle car torque. Not the same .
That's exactly what I've always said, but everybody says how great the LS engines are ( and they are nice engines) I thought it was just me not feeling the low end torque.
LS and Hemi engines are car engines, NOT truck engines. They all lack torque at a lower RPM (under 3000). If you like to tow at 4000 rpm all day then you're OK.
I think the worst are the Ford OHC engines in trucks, you can hear the engines rev when starting out from a red light like they have 5.13 gears
When I see the "Hemi" badge on a Ram truck, Im not impressed, yeah its a cool engine, but its saddled with 3 plus tons of lard
Couple days ago I was watching a vid of a Nelson built 260 cu.in. twin turbo LS for a racing boat, it was over 1000 hp. One of the comments was " how much torque tho?" Someone replied "Boats don't need torque" I replied " Oh yes they do"
Anybody know if Mercruiser is still using the traditional Chevy small and big blocks?
I think an LS in a boat would be a dog.
GM addressed this low torque issue with the new 6.6L LT truck engine that replaces the 6.0L in the 2600/3500 PU trucks. I just read that this 6.6 will be an option in the 1500 also.
Bore & Stroke (in / mm): 4.06 x 3.86 / 103.25 x 98
by installing this 3.86 stroke in 5.3L its about same as 350 buick
The 6.0 is pretty good but it needs long tube headers and a custom tune to wake it up. The factory tune is terrible. I can tow a 3500 pound car on my 2000 pound trailer at 70 mph at 2000 rpm without an issue.
Stock 6.0's are dogs.
All they need is headers, good exhaust and a computer tune.
not sure how headers will help lack of torque. Maybe the tune would help but can't imagine GM was that far off. unless its an emissions issue.
Ive never seen an engine that didn’t gain low RPM torque with a nice set of long tube headers scavenging the exhaust.
yes the headers helped the lack of low RPM torque even before I did the tune. It was noticeable, it can pull a trailer the Buick on it at 1800-2200 RPM on the highway now. Stock it geared down and ran 3000 RPM on flats. Now it pulls up hills at 3000-3200. Dual 3” with magnaflow mufflers. The tunes GM has on them are terrible. Guys are gaining 20-30 Hp just in the tune with no mods. Headers are 20 hp and 15 foot of TQ gain before the computer tune is optimized. A cam swap is an easy 50 HP without loosing any bottom end torque. Or 75+ hp if you can afford to give up some down low.
plus my truck has a 4.03 first gear ratio in the 6L80E which is the equivalent of running a 6.00 gear with a TH-350. No shortage of grunt off the line and still has enough torque to push the truck to 100 mph at 2400 RPM in 6th gear. That’s a 7915 pound truck (scaled) with 3.73 gears, 35” off road tires, 6” lift, two winches and tools. I’ve pulled a 10,500 pound trailer, it did fine. I liked it so much I bought a spare 2wd drivetrain to swap into something light like a S-10.
I've noticed that the past few years, OEM's adding more ratio's (gears) to their auto transmissions to multiply the available torque so the engine doesn't seem so lazy off the line, its almost as if they're masking the low end torque deficit, especially 4 cyl. engines.
The added ratios down low are multiplying what little torque the engine is developing.
So is it the engine, or the trans?
Yes I hear ya... IN general I agree, lots of engines running around that SEEM to make great torque but they just have serious gear multiplication. But the true test is going up a hill at 80 MPH, if the vehicle needs to drop 3 gears to hold speed then the engine makes no torque.. If the engine is like mine and holds 6th gear up hills then you know you have the torque.
No, that will only buy you a roller cam setup, roller rockers & pushrods and an SP3 intake.
most mild street builds don’t need any of those items ...