lq4 408 build questions
05-08-2017, 08:14 PM
#1
lq4 408 build questions hey guys, what would be the best 408 ls stroker kit to go on my lq4? also what cam heads? its going in a 1990 s10 with a 4L80e being built, what should I look for when building it? what HP should it make? any help will be great!
05-10-2017, 12:06 PM
#3
I used a Callies brand kit. It is a Comp Star 4" crank, Comp Star 6.125" connecting rods and CP Bullet -3cc flat top pistons. I am very pleased with the kit. Make sure you order it with the optional billet reluctor wheel. I think it is about $2500.00
05-18-2017, 05:52 PM
#6
I have seen so much trouble with many stroker builds. I don't know if its just from lack of knowledge, improper parts or what. And the vas majority of them around here don't run as good as mine and if they do its just barely. There are some out there like Steve's, but I've seen more fail than impress. Id stay stock cubes and spray or turbo.
05-18-2017, 05:57 PM
#7
the longer stroke pulls the piston too far out of the bottom of the cylinder and allows the piston to rock. over time the rocking piston gets worn out while making an egg shape out of the base of you cylinder wall. I just picked up a lq4 to build into a stock crank forged 370 as a back up for my 408...I've had 2 fully forged 408 motors in the past built by a "professional" and didn't have much luck with them. this is my third 408 and I don't have a warm fuzzy feeling about the life expectancy.
if it's up to me, stock bottoms all the way...or stock bottom with forged pistons.
st
if it's up to me, stock bottoms all the way...or stock bottom with forged pistons.
st
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05-18-2017, 08:03 PM
#8
A 4 inch stroke on any ls block is fine. It wont have any issues as long as the rings are gapped right and the piston to bore is machined right. Machine work is key. We have quite a few 408 stroker kits available and our gasket kit prices cannot be beat!
You want more info, email me
Rpmspeedtech@gmail.com
You want more info, email me
Rpmspeedtech@gmail.com
05-18-2017, 09:17 PM
#9
The one in particular I am talking about was built 3 times to make 6 passes. It was a 43? stroker. It was built by a VERY big name builder here in the south. We also took a 5.3 there before we knew of all these problems. The bore was not bored all the way thru, the heads were both different cc, the valve job looked like a 12 year old did it. He was paid almost 2000 dollars for the parts and machine work. With 2 chances to get it right. It ended up at anotehr machine shop and had another 1k spent on it in machine work. At least the guy that did it this time, we know did it right. Weve known him for 30 years.
05-19-2017, 01:22 PM
#12
Im sure there are plenty that would. Esp piston manuf and crank manuf. And the thousands of 408s + out there.
Id trust Steve at RED first post #2
https://ls1tech.com/forums/generation-iv-internal-engine/569680-block-sleeve-length-ls1-ls2-ls6-ls7-l92.html
NRE has built a 402 ls2...so what is the difference? He even had twin rotrex on it.
https://youtu.be/6-GXXbg0Ygg
http://www.nelsonracingengines.com/videos/on-the-dyno/NRE-LS2-FI-Twin-Rotex-Blowers.html
He is right on a few points, but what he does not stress enough is proper machining. He talks about assembly, but you cant expect some joe schmoe macnine shop used to working sbcs over do a good job on an ls with new piston design etc. Proper machine work is tantamount to any good engine build. Otherwise it really sounds like his sales pitch is aimed at only selling his very expensive engines and only using resleeved or lsx/aftermarket blocks. You dont see him make a TT4.8 or 5.3 out of a truck block...at least not that google would show. Maybe his argument is stock blocks are for stock rides? The 800+ hp 4.8/5.3 guys would beg to differ. Seems budget isnt in his wheelhouse.
Maybe tell lme, tsp, sdpc, etc etc to stop building 408s+ because nelson says so. I am really jumping on a soap box because what he says happens on stock engines and not because the stroke is too long. It was bad piston design.
/rant
Id trust Steve at RED first post #2
https://ls1tech.com/forums/generation-iv-internal-engine/569680-block-sleeve-length-ls1-ls2-ls6-ls7-l92.html
NRE has built a 402 ls2...so what is the difference? He even had twin rotrex on it.
https://youtu.be/6-GXXbg0Ygg
http://www.nelsonracingengines.com/videos/on-the-dyno/NRE-LS2-FI-Twin-Rotex-Blowers.html
He is right on a few points, but what he does not stress enough is proper machining. He talks about assembly, but you cant expect some joe schmoe macnine shop used to working sbcs over do a good job on an ls with new piston design etc. Proper machine work is tantamount to any good engine build. Otherwise it really sounds like his sales pitch is aimed at only selling his very expensive engines and only using resleeved or lsx/aftermarket blocks. You dont see him make a TT4.8 or 5.3 out of a truck block...at least not that google would show. Maybe his argument is stock blocks are for stock rides? The 800+ hp 4.8/5.3 guys would beg to differ. Seems budget isnt in his wheelhouse.
Maybe tell lme, tsp, sdpc, etc etc to stop building 408s+ because nelson says so. I am really jumping on a soap box because what he says happens on stock engines and not because the stroke is too long. It was bad piston design.
/rant
05-19-2017, 03:15 PM
#14
A 370 na or nitrous wont make nearly the power a 408 would. Take a cam from a 408 and put into a 370 theyll act completely different.
As long as the engine is built correctly you have nothing to worry about.
Buying a car with a 408 the only things youd need worry about is what oil did they use and was it changed on time with a quality filter.
Going from a 2618 to a 4032 forging in an na or nitrous app can fix alot of issues related to oil consumption due to tighter piston to bore clearance, but that's a moot point in an already running engine. So can std tension vs low tension oil rings.
As long as the engine is built correctly you have nothing to worry about.
Buying a car with a 408 the only things youd need worry about is what oil did they use and was it changed on time with a quality filter.
Going from a 2618 to a 4032 forging in an na or nitrous app can fix alot of issues related to oil consumption due to tighter piston to bore clearance, but that's a moot point in an already running engine. So can std tension vs low tension oil rings.
05-21-2017, 08:59 AM
#15
interesting topic. for those that had issues with stroked 6.0s i wonder if they daily drive , weekend car , or track car? also what rpm they spin to. i always wanted to have a 408 but the internet is good at having conflicting info.
05-23-2017, 12:05 PM
#17
430 LS was on the dyno last night. On methanol, Frankenstein LS3 heads, not sure of bore and stroke. Cam is a comp, don't know specs. Super Vic, 950 carb. Max power was 672hp. I don't see much benefit here. His old motor was on dyno, made 618 fwhp. On a dynojet dyno, it made 462 (iron 6.0 bored to 6.2)to the tires on methanol.This was thru a glide . My car on the other hand hasn't been on the engine Dyno, but did make 497 going lean above 5800 to the tire. That should easily put my 376 sbe in the 640 range. with stock milled heads. I'm not being impressed by many strokers yet.
05-23-2017, 12:45 PM
#18
430 LS was on the dyno last night. On methanol, Frankenstein LS3 heads, not sure of bore and stroke. Cam is a comp, don't know specs. Super Vic, 950 carb. Max power was 672hp. I don't see much benefit here. His old motor was on dyno, made 618 fwhp. On a dynojet dyno, it made 462 (iron 6.0 bored to 6.2)to the tires on methanol.This was thru a glide . My car on the other hand hasn't been on the engine Dyno, but did make 497 going lean above 5800 to the tire. That should easily put my 376 sbe in the 640 range. with stock milled heads. I'm not being impressed by many strokers yet.
05-23-2017, 01:32 PM
#19
My old 6.0 with CNC 243s and a Vic Jr made 467 on a dynojet chassis dyno. In great weather. The car went 98 MPH to the 1/8th in very good weather at #3700. My 403 with As Cast Pro1 LS3 heads and a Vic Jr. went over 103 MPH to the 1/8th in 2000+ D/A first time out with a nitrous stall and less rear gear. On a medium sized shot, the stroker has gone 116.5 in the 1/8th in the heat of the summer. The old 6 liter would only go 109 on the same shot in good weather. I am thrilled with my stroker.
05-23-2017, 04:12 PM
#20
A 370 na or nitrous wont make nearly the power a 408 would. Take a cam from a 408 and put into a 370 theyll act completely different.
As long as the engine is built correctly you have nothing to worry about.
Buying a car with a 408 the only things youd need worry about is what oil did they use and was it changed on time with a quality filter.
Going from a 2618 to a 4032 forging in an na or nitrous app can fix alot of issues related to oil consumption due to tighter piston to bore clearance, but that's a moot point in an already running engine. So can std tension vs low tension oil rings.
As long as the engine is built correctly you have nothing to worry about.
Buying a car with a 408 the only things youd need worry about is what oil did they use and was it changed on time with a quality filter.
Going from a 2618 to a 4032 forging in an na or nitrous app can fix alot of issues related to oil consumption due to tighter piston to bore clearance, but that's a moot point in an already running engine. So can std tension vs low tension oil rings.
you act like worn out skirts and egg shaped cylinders are an uncommon occurrence with stroker builds...i've seen examples from well known builders. and no, the builders wont stop cranking them out...it's money in their pockets. a stroker has its place...just short lived as a daily driver from what i've seen. especially when the money put towrads that bottom end can go towards some forced induction that would blow any N/A 408 out of the water.