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Nitroracer
Nitroracer SuperDork
7/31/11 3:33 p.m.

What seems to be the weak link in the high rpm LS Engine?

I did a little digging around looking for a way to make my LS1 scream and the weak link appears to be rod bolts. The rest of the information was people telling you not to build it because torque is awesome.

BoostedBrandon
BoostedBrandon Reader
7/31/11 10:48 p.m.

Hot Rod's 1200 hp 4.8 had ARP rod bolts, as well as enlarged top ring gaps, new lifters, a comp bumpstick, better springs and a larger throttle body and intake, as well as stage 1.5 ported heads. The stock 120,000 mile crank, rods, and pistons were used.

Basically, the typical high-RPM formula. Then add boost, subtract traction, equals giggles!

oldopelguy
oldopelguy Dork
8/1/11 3:31 a.m.
NGTD wrote: My dad used to have a 283 in a 38 Chev coupe and he used to turn it to 7500. The 4.8 would be similar displacement - The 5.3 is almost identical to the old 327 and some purists will swear that the 327 was the best SBC ever made.

The new 5.3 has nearly the same displacement as the old 327, but with a longer stroke and smaller bore.

Hot ticket would be to combine a cheap 4.8L motor, a used LS1 5.7L block and pistons. Bore and stroke would then be almost exactly the same as the old 327, but all aluminum and with the LS-heads from the 4.8L.

Lots of folks insist the 5.3L motors will bore out to 5.7L though as well, which might mean all you would need is a 4.8L, some pistons, and a gasket set.

Strike_Zero
Strike_Zero HalfDork
8/1/11 9:10 a.m.

Gen III/IV engine bore and stoke combos

3.779" bore combinations

  • 3.268" stroke: 293.2ci or 4.8L (Stock 4.8L combo)
  • 3.622" stroke: 325.0ci or 5.3L (Stock 5.3L combo)
  • 4.000" stroke: 358.9ci or 5.9L
  • 4.125" stroke: 370.1ci or 6.1L

3.898" bore combinations

  • 3.268" stroke: 312.0ci or 5.1L
  • 3.622" stroke: 345.8ci or 5.7L (Stock 5.7L combo)
  • 4.000" stroke: 381.9ci or 6.3L
  • 4.125" stroke: 393.8ci or 6.4L

4.000" bore combinations

  • 3.268" stroke: 328.5ci or 5.4L
  • 3.622" stroke: 364.1ci or 6.0L (Stock 6.0L combo)
  • 4.000" stroke: 402.1ci or 6.6L
  • 4.125" stroke: 414.7ci or 6.8L

4.065" bore combinations

  • 3.268" stroke: 339.3ci or 5.6L
  • 3.622" stroke: 376.1ci or 6.2L (Stock 6.2L combo)
  • 4.000" stroke: 415.3ci or 6.8L
  • 4.125" stroke: 428.3ci or 7.0L

4.125" bore combinations

  • 3.268" stroke: 349.4ci or 5.7L
  • 3.622" stroke: 387.2ci or 6.3L
  • 4.000" stroke: 427.6ci or 7.0L (Stock 7.0L combo)
  • 4.125" stroke: 441.1ci or 7.2L
cwh
cwh SuperDork
8/1/11 10:07 a.m.

Keep in mind that Hot Rod got well over 400HP BEFORE the turbo madness. Not bad for 293ci with a cam and minor headwork.

Greg Voth
Greg Voth HalfDork
8/1/11 10:59 a.m.

Reading this has made me want to defile my nice blue RX-7. (not to be confused with the other 3)

Doesn't help that I found a 87,000 mile LS1/T-56 combo 20 minutes up the road for $3,000 and will include everything I want from the donor car.

Strike_Zero
Strike_Zero HalfDork
8/1/11 4:47 p.m.

BUY NOW!!

MrJoshua
MrJoshua SuperDork
8/1/11 5:56 p.m.

In reply to Greg Voth:

Offer $2500 cash- then BUY NOW!!!

ValuePack
ValuePack Dork
8/1/11 7:50 p.m.

Positively none of this thread makes it easier to NOT buy a Roadmaster for a new daily...

Vigo
Vigo Dork
8/1/11 8:18 p.m.
Jesus H., where do you live? Is it rusty (it doesn't look like it, and my current one is). I could totally bring that up from the states...

Sorry for the late response.. i live in Texas (as far from Canada as possible) and the car was repainted around 10 yrs ago. No rust that i have seen and i have been over it pretty well.

Greg Voth
Greg Voth HalfDork
8/2/11 12:46 a.m.
MrJoshua wrote: In reply to Greg Voth: Offer $2500 cash- then BUY NOW!!!

Believe me I want to. I doubt they would take it being a Junkyard and all. They did however knock $700 of the list price if I purchase it as a combo.

I should be able to sell the motor and related stuff out of the RX-7 to Zero out the purchase. I'm pretty sure I could throw it in there with some left over bolts and a welder making it cost nothing

It doesn't help that I dont exactly have $3,000 sitting around especially after entering the Chumpcar Race at Sebring, and trying to get that car ready. Plus I still need saftey gear.

aussiesmg
aussiesmg UltimaDork
3/31/13 6:29 p.m.

Back from the dead, what manual transmission can handle the boosted power of a decent 4.8.

Knurled
Knurled GRM+ Memberand UltraDork
3/31/13 7:00 p.m.

Lenco?

You can make more power with a 4.8 than you can put transmission behind it if you want an H-gate manual.

Dusterbd13
Dusterbd13 HalfDork
3/31/13 8:45 p.m.

im not a fan of LS swaps, as a rule. but berkeley, this is making it difficult NOT to go buy the complete, can hear it run and ghet as much of the drivetrain as you want 4.8 oncraigslist for my elky....

now im going to be looking at LS swaps. i akready have an LS1 intake and throttle body laying around too. wonder if the truck exhausty manifolds will clear my a-body frame?

thanks, guys,.....

patgizz
patgizz GRM+ Memberand UberDork
3/31/13 9:22 p.m.
aussiesmg wrote: Back from the dead, what manual transmission can handle the boosted power of a decent 4.8.

camaro t56?

or any old 4 speed if you don't want overdrive.

aussiesmg
aussiesmg UltimaDork
3/31/13 9:26 p.m.
patgizz wrote:
aussiesmg wrote: Back from the dead, what manual transmission can handle the boosted power of a decent 4.8.
camaro t56? or any old 4 speed if you don't want overdrive.

No way can the T56 handle 700 plus hp and torque that would be even higher

Catatafish
Catatafish Reader
4/1/13 12:58 a.m.

Viper spec could!

aussiesmg
aussiesmg UltimaDork
4/1/13 6:29 a.m.

What manual transaxle?

Strike_Zero
Strike_Zero Dork
4/1/13 6:48 a.m.

Nascar spec 4-speeds (Jericho, Tex, G-Force) and Viper spec trans. You can get a pedestrian T-56 built to handle whatever you can throw at it.

dyintorace
dyintorace GRM+ Memberand UltraDork
4/1/13 8:30 a.m.
oldopelguy wrote:
NGTD wrote: My dad used to have a 283 in a 38 Chev coupe and he used to turn it to 7500. The 4.8 would be similar displacement - The 5.3 is almost identical to the old 327 and some purists will swear that the 327 was the best SBC ever made.
The new 5.3 has nearly the same displacement as the old 327, but with a longer stroke and smaller bore. Hot ticket would be to combine a cheap 4.8L motor, a used LS1 5.7L block and pistons. Bore and stroke would then be almost exactly the same as the old 327, but all aluminum and with the LS-heads from the 4.8L. Lots of folks insist the 5.3L motors will bore out to 5.7L though as well, which might mean all you would need is a 4.8L, some pistons, and a gasket set.

At the risk of further exposing my lack of automotive mechanical knowledge, what's the difference between a motor and a block, as used in the bolded section above?

Greg Voth
Greg Voth Dork
4/1/13 8:53 a.m.

I had forgotten about this thread. So I got the LS1/T56 I posted about earlier in the thread for $2500. Then about a month ago picked up complete 4.8 for $150.

Aside from gathering parts (LS6 intake/heads/cam/clutch) nothing has happened with either.

Strike_Zero
Strike_Zero Dork
4/1/13 9:13 a.m.
dyintorace wrote:
oldopelguy wrote:
NGTD wrote: My dad used to have a 283 in a 38 Chev coupe and he used to turn it to 7500. The 4.8 would be similar displacement - The 5.3 is almost identical to the old 327 and some purists will swear that the 327 was the best SBC ever made.
The new 5.3 has nearly the same displacement as the old 327, but with a longer stroke and smaller bore. Hot ticket would be to combine a cheap 4.8L motor, a used LS1 5.7L block and pistons. Bore and stroke would then be almost exactly the same as the old 327, but all aluminum and with the LS-heads from the 4.8L. Lots of folks insist the 5.3L motors will bore out to 5.7L though as well, which might mean all you would need is a 4.8L, some pistons, and a gasket set.
At the risk of further exposing my lack of automotive mechanical knowledge, what's the difference between a motor and a block, as used in the bolded section above?
  • 4.8L = iron block
  • LS1 = aluminum block

I believe the max bore is 3.905 for both. Lots of guys bore a 5.3 to fit LS1 pistons (iron LS1). A stock bore LS1 with a 4.8 crank is 312ci. See my post above for bore and stroke combos.

Bobzilla
Bobzilla UltraDork
4/1/13 9:52 a.m.
Strike_Zero wrote:
dyintorace wrote:
oldopelguy wrote:
NGTD wrote: My dad used to have a 283 in a 38 Chev coupe and he used to turn it to 7500. The 4.8 would be similar displacement - The 5.3 is almost identical to the old 327 and some purists will swear that the 327 was the best SBC ever made.
The new 5.3 has nearly the same displacement as the old 327, but with a longer stroke and smaller bore. Hot ticket would be to combine a cheap 4.8L motor, a used LS1 5.7L block and pistons. Bore and stroke would then be almost exactly the same as the old 327, but all aluminum and with the LS-heads from the 4.8L. Lots of folks insist the 5.3L motors will bore out to 5.7L though as well, which might mean all you would need is a 4.8L, some pistons, and a gasket set.
At the risk of further exposing my lack of automotive mechanical knowledge, what's the difference between a motor and a block, as used in the bolded section above?
- 4.8L = iron block - LS1 = aluminum block I believe the max bore is 3.905 for both. Lots of guys bore a 5.3 to fit LS1 pistons (iron LS1). A stock bore LS1 with a 4.8 crank is 312ci. See my post above for bore and stroke combos.

The hotter ticket would be the 6.0L LQ4/LS2 block/pistons. That's the 4" bore, then use the shorter stroke of the 4.8 (3.27, compared to the 3.62 of the 6.0) with the longer 6.278 rods of the 4.8. That would be a little beast. crank the compression up a little, add a nice cam and you'd have a nice 450hp N/A high revving beast.

Strike_Zero
Strike_Zero Dork
4/1/13 10:25 a.m.

^This!!!!

I have a 4.8 crank and rods on the shelf for this.

243, 799, or L92/LS3 heads + LS6 or L92 intake would make a tasty motor.

Bobzilla
Bobzilla UltraDork
4/1/13 10:49 a.m.

I just drove my LR4-equipped crewcab in this morning and remember just how lovely it sounds at 5k rpms going under the overpass here by work...... Magnaflow sounds gooooooood.

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