Would using the LT1 internals be better than using the stock L98 internals?

I have heard that the pistons are short skirt type and they are lighter as well as the rods. Is this true?

If it is, are the internals of the LT1 a direct bolt in for an L98?

TIA

 

The LT1 pistons & PM rods are lighter. Consequently the LT1 crank counter weights are lighter making a light rotating assembly.

 

They are a direct bolt in but they don't have any real advantage. Both use cast pistons and they may actually use the same crank. Internals aren't that much so you may want to invest in a nice hyper set with some better than average rods and crank.

 

What if the LT1 was really cheap from a friend. I think that he only want's $150 for it (the shortblock).

 

the piston in the lt1 are hypereutectics, not cast...
the rods are stronger aswell..
and im almost 100% positive that crank is nodular rather then cast..

its also lighter like mentioned..and actually the LB9 rotating assembly is nearly the same weight as the LT1

 

Yea you are exactly right. Thats what you get for posting as soon as you wake up. I was sitting in class and I was like "uhh I am completely wrong about the pistons." You'd think from someone who owns one they would be able to rattle that off witout any errors.

 

Early LT1 engines (not the 1970 variety, but the earliest models of the last iteration) were equipped with the standard old cast billet/forged con rods, L98 crank, and cast pistons. Some time in 1994, LT1s got the powdered metal/forged con rods and lighter pistons, as well as a new crankshaft. The cranks for the later LT1s were lighter than the L98 cranks, and closer to the SBC 305 crank in counterbalance weights.

If you call that "better", then, yes, it's better. It is also dimensionally the same as the L98 crank in journal sizes, stroke, and all other significant dimensions. The entire rotating assembly from an LT1 can be installed in the L98 block. If you get the entire short block, you might just as well use that if you can, since most of them were the higher nickel content castings, but were also set up for the camshaft water pump drive and split coolant ports on the front wall of the block. That may be a challenge if you don't go all LT1 systems.

You would also be better off using the LT1 harmonic balancer (two-piece) than the standard SBC balancer.

The standard quoted figure for safe power limits on the LT1 stock internals is 450 HP on a two-bolt crank. I found that the one I rebuilt was fairly well balanced from the factory. The PM rods were better balanced than any cast/forged stock "set" I've ever measured. I can only presume the improved and more precise production methods are responsible for the better weight match and distribution from end-to-end.

EDIT: I hope we get a spell-check feature on the new board sftware. OH:

 

So if I finf an LT1 short block I would just have to use my L98 cylinder heads and intake as well as my engine accesories and that's it? I mean Is it really a direct bolt-in ? I blew my engine this morning and just might be able to get my hands on an LT1 short-block. I was thinking about using it or using the internals. The rods are 6" in the LT1s. I heard it is a better rod ratio with the 3.48 crank but a new cam timing should be used. Is that accurate? Thanks

 

NO the LT1 motor is REVERSE cooled meaning that heads get the coolant first..there are also no intake crossover ports...
the "BABY" LT1 had the 6 inch rods, the "350" had the 5.7 rods..

 

Are you positive on this? I heard LS1s are the ones with reverse coolant flow. If you're right then it means I can't use an LT! short-block with my L98's heads, intake and accesories? How about using just the internals with my L98 block?

 

f-crazy is dead on. Both LS1's and LT1's are reverse cooled engines.

 

LT1 are reversed cooled. You can't swap heads, easily that is.

 

beam width grams------------beam width-
---------------------------------------------------------------------------------
350rod['89/earlier]------600--------------------.570
350rod['89/later]--------602--------------------.505
Crower Sportsman------712--------------------.685
[5.850.inch]


source John Lingenfelter: On modifyng small block chevy engines HPBOOKS-1238
L98--thickie rods---:rockon:

 

Well, I guess I'll just take my crank to the machine shop and buy an used set of rods. The block should be ok, I hope Offset grinding and .060 over pistons and I'll have a 6.0L SuperRam engine I just hope everything else is ok. I blew my engine today just for the record

 

I was wondering, aren't some of the later l98's reverse coolant flow blocks? I thought mine was and it's an 89. If this is so, wouldn't the l98 heads bolt up to the lt1 shortblock? Thanks for any info.

 

Not sure about the pistons and crank being better, but I know the rods are quite a bit better in the LT1.

 

You don't want his crap, go ahead and give me his email, I like to collect junk.

 

False. Reverse cooling didn't apear until the Gen II motors arrived. Every L98 was Gen I.

 

Sorry for bringing this one back, I lost it a while ago.

I bought the engine and sold it to a member down in Austin that is finishing it up now.

However, I do have another LT1.

Last question: The block is from the cop caprice 8C1 cars, is there a difference in the internals there?

 

Is it a 5.7?

 

Yes it is.

 

Cop cars had iron heads and thinner head gaskets for a tad more compression. Seems like maybe they had a slightly different cam for more torque. Otherwise the same as LT1. Cooling ports in block won't match up to L98 heads and the TPI won't bolt to LT1 heads so it is tough to combine the engines.

 

its 9C1 just to let you know....and you couldnt get the police package without the 350...

 

Doh, wrong key. Yeah I knew that.