29 originally, 2 destroyed, leaving 27 if my memory serves me correctly...there was one for sale on the st. louis area craiglist last fall...I was VERY tempted...

 

Fathers one owner non rebuilt factory LT1 in his 96Z was a 4 bolt main car. We put a 355 in it about 6-7 years ago and that thing still dosnt have a 1000 miles on it, probably not even broke in lol.

Im 100% sure its a 4 bolt main as Im using it for my forged bottem end build and I use it all the time to mock up heads and intakes for port geometry.

The one in my 94TA was a 2 bolt and pops 355" was a 2 bolt, oh well it dosnt make a damn difference anyways.

Listen to everyone here and dont **** around looking for one of these 4bolt blocks, just get your 2 bolt setup splayed or studs and it will be overkill for 99% of the power you will ever make. Im reusing my 2 bolt block and having it refreshed with hone/rings and bearings and oil pump and Im still going to spin it to 7500rpms. I would rather save the 4 bolt for nicer forged parts since I already have it laying around and would hate to kill it with stock parts.

 

Just for the info since this thread is talking about lt4 engin install in a f-body.I was the guy who bought the las lt4 crate motor from gm factory.GM sent me all the paper with it.I know that for some it wasnt a good choice but a LT4 crate motor for 3k...i couldnt resist

I put it in my bird and im really happy with it

 

Personally I'd agree that the 2 bolt to 4 bolt conversion is better, and even more most people ARE fine with the two bolt. The stock 2 bolt bottom end, factory crank and rods are good for a bit more than 500 hp. I'm in that horsepower range with a 100 shot so I sure as hell hope so

 

Sounds fun I know the LT4's were supposed to have a little more love in the build process so it can handle the higher factory rev limit. Even though I know its a waste of cash buying LT4 heads intake etc, I just think they are cool and wouldnt mind having one to play around with. I think my next buy will be a ragged 96 6spd vette so I can score the factory LT4 parts and have fun restoring the thing with my father and son.

Always was a sucker for special factory parts, like the LS6-LS7 rectangle port bigblock heads I wish I never sold to buy a beautiful back door and stainless fridge for the kitchen lol. Oh well cars are around always family is more important...

 

I would doubt that. Most if not all GM engines from that era were assembled on automated lines by machines.

Somewhere on youtube, there's a video of heads being bolted down by machine with blocks coming down one line and heads another. Machined parts in one end, assembled engines out the other.

Other than today's LS7/LS9/LSA engines, which are hand built, it's still the same.

 

Did I say handbuilt???????????????

Im talking about the crankshaft with undercut and rolled fillets giving much better bearing tolerance's and creates the high tensile strength point to make the crank design more stout. Has a roller timing chain with steel gears not powered metal like LT1. Different harmonic dampener and as you know superior as cast heads, who wouldnt like to have a set of those sodium filled valves to toss in there LT1 heads??? Fractured cap rods in all the LT4's that the later year LT1 also have as I have three sets of those un machinable piles of scrap

Im not saying they are not mass assembled just better machine work that Im 100% sure of. After holding a lt4 rotating assembly in my hands and a LT1 setup directly beside it using a micrometer and depth calipers you can clearly tell its better machine work over LT1.

Im not nuthugging on the LT4 but I wouldnt toss it out of bed if one made the moves on me

 

Also forgot about the revised piston design to allow a more shallow dish to raise compression, or the rings used to seal the combustion by using positive twist lock rings.
Lets not forget about the nodular iron main caps that im sure were not needed but is nice to have over a two bolt block, teflon rear main seal to rid of the common leaking LT1 design.

 

How many LT1 crank failures are there with stock cranks?? So the undercut and rolled fillets is nice on paper but without added value practice.

A guy started a thread on stock LT1 timing set reliability and let's just say that even on setups like mine the LT1 set was shown to do the job WELL. So again a "upgrade" of questionable tangible benefit.

The valves are nice I will give it that BUT modern springs let us get away with a LOT before needing something so exotic.