gn4life

iTrader: (3)

So I know I want to go JUNK YARD GM LS 5.3 for my winter project car. Just cant choose which way.

Mods will be:
Cheap Turbo /Intercooler (Ebay style)
Rod bolts
Cam 22X boost cam
Stock, Ported, milled heads
Ls6 intake
Underdrive Pulley
Meth Kit
Comp 918 springs
chrome molly pushrods
the cheapest lifters I can get away with

I was all set to buy a full Junkyard GM Vortec 5.3

Then I saw I could get a low mileage LS4 for like $100-$200 more...

I know the LS4 is all alluminum. which is sweeet cause the whole point of this car is to make it as light as I can cause its mid-engined. And turbos add a ton of weight. So this would help counter that.

1. How much lighter is it than the iron block Vortec???

2. Can a LS4 on boost make the same power with the same mods as the Vortec 5.3????

3. Do they have the same heads????

DavidPHumes

iTrader: (1)

Almost positive you can't run an LS4 as the bell housing bolt hole locations are different to accommodate a FWD transmission

Troy5061

iTrader: (19)

Not the same bolt pattern.

gn4life

iTrader: (3)

No matter what, I know a custom adapter plate would need to be made....

The engine is being mated to a porsche transaxle....


But do the LS4 block and the 5.3 Vortech share the same mounts???

Like in theory could I put an LS4 block in a cradle that was made for a 5.3 without any custon motor mounts???

gimmeluvin

iTrader: (10)

geez those are some big **** in your sig

supercatxr7

iTrader: (5)

Heads are 243's and that is correct above that the bell housing is different to accomodate the 4T65EHD transmission.

slow98Z

iTrader: (27)

they share the same bolt pattern its the depth on the flywheel flange thats different

Black98s10

I have seen a guy put a ls4 in a s10, but it was tons more work than a LM7. Different accessories, different intake, and some other things were swapped out. He has a video on youtube.

fieroguru

iTrader: (1)

The LS4 uses the GM Metric pattern, not the old SBC pattern that the RWD LS engine use.


It you look close, the Metric pattern is raised from the SBC flange, so the LS4 block is about 1/8" longer than the RWD blocks.

The crankshaft is 13mm shorter, 3mm at the flywheel and 10mm at the balancer end.

The accessory drive is quite compact (length wise) with the balancer up tight against the block. Here is a pic of a RWD truck water pump over a LS4 balancer (notice the pump is about 3/8" away from the block due to contact with the cam sensor).


The LS4 uses the 243/799 heads, but the intake is quite restrictive (D-shaped to clear the OPSU).

The LS4 also has no provisions for an engine mounted starter - their starter was transmission mounted.

Black98s10

If you're worried bout weight but still want a rwd engine, what about looking into the aluminum 5.3's from the trailblazers and envoys?

JAX04

iTrader: (17)

Yep, LM4, L33, good choices. The l33 is newer and has better rods.