ok guys im planning on getting a loan from the bank(only 18 and dont know how much i can get approved for) i want to swap my engine although i dont know what motor to get.
im looking for better gas mileage and more HP. i dont know if i should go with a L98,LT1,or LS1 does anybody know what the hp and mpg these motors have and which one would best fit my needs

 

Stock L98 has 225-240hp and 275-300ft/lbs
Lt1 has 275hp and 3xxft/lbs
LS1 has 325hp and 3xxft/lbs

depends on your money, time frame, emmissons and knowledge.

i say LT1. it will mount using stock mounts. has a good amount of power stock to keep you amused. any headers made for a thirdgen with a sbc will bolt onto the lt1. can be had for cheaper then LS1's.

 

i'm going to also go with the LT1 it would provide descent hp with good gasmilage.. not to mention it would pass emissions easily stock of course..

 

will a LT1 out of a vette mount right up too or are the mounts diff on the vette version?

 

i have already done the LT1/T56 swap

if you buy one you need to go ahead and replace all of the opti parts and ignition

it is a pain in the *** to do it in the car! also you should go ahead and get the electric h2o pump and an aftermarket harness($550) from howell engineering

i personally would go with a L98 motor because it is entirely plug and play by that i mean the wiring harness will go right in and there is no need for custom modification

i put a kmember and long tube headers on my car when i did it so some things have been 10x easier

if you plan on keeping AC you have to have custom lines made and if you keep stock kmember you will have to notch it also you have to custom make some PS lines which is very easy to do

if you have any specific questions let me know and i can try to answer them

 

First, you should not go with some $500 harness from anyone, use the factory harness, second you probably shouldnt go with an electric pump if this is to be a daily driver, if it fails you'll be out a car provided you dont check the gauge every 30 seconds, third get a good motor that you know runs and install it as is, the more things you go replacing before the swap the more that are possibilities if it doesnt start and anyone who has trouble swapping the opti on an LT1 thirdgen probably shouldnt have done the swap in the first place.

The L98 may plug right up, but the benifits of the LT1 far outweigh having to splice a few wires.

 

tell me exactly what the benefits are of the LT1 over the L98

i had no problem with the swap because i knew what i was doing and having a race car with my dad(94Z28) i know all i need about the LT1s and i picked it up for a good deal


i would run a L98 anyday over an LT1 for a street car because down low the power is 10x greater

 

The opti is ridiculously easy to replace, especially in a thirdgen! Only pain in the *** is re-doing the gaskets but I just goobed it up with some RTV, took 35 minutes from tear apart to completion. I agree, anyone who has trouble replacing an opti spark, shouldn't be swapping a motor.

 

The more your post count goes up so far the more you sound like someone not to be listening to.

1st you are stupid for saying you'd take a L98 over an LT1 for a street car, the L98 doesnt make anywhere near 10x down low, it makes a higher torque peak, however the LT1 has a MUCH more broad torque powerband, on the street you are typically limited by street tires, so there goes planting either the 345 ft lbs a L98 has or the 335 a LT1 has anyway, so you're dead even off the line due to traction, and by the time you get moving the LT1 has burned a hole so far into your car it isnt even funny.

Benefits of the LT1 over an L98

1. an intake that actually flows worth using, dont try and say but you can get this and that for a tpi, it will run you just about the cost of a used LT1 to upgrade the tpi setup and it still wont flow as good as the LT1 intake manifold.

2. Stock aluminum heads that are worth using, a good ported set of stock heads is capable of 420 + rwhp.

3. the computer is faster, better and more efficient than the tpi one as well as the maf being capable of reading more airflow than an L98 maf setup

4. it is much easier to build a fast LT1 that will pass emissions than a fast tpi car that will, see #1

5. No coolant flowing through intake, makes for no problem intake gasket swaps, easier camshaft swap, and for those that want to get wild, easy jet changes with an under manifold nitrous system since you dont have to worry about getting coolant into the lifter valley pulling the intake, it would be very feaseable to pull the manifold at the track with no problems and make changes.

6. it has a more compact front drive setup, fits better than an L98 setup and easier to work on

7. easier to work on with full emissions equipment in tact

I think thats enough.

 

Don't forget that you will need to change the fuel pump to a higher flowing pump (if you have an in-tank pump) as well.

I'm going to be doing an LT1 swap in my '86 when I get the fundage to do it and more than likely will be using the accessory setup for a Corvette since the AC compressor is in a different location on them.

 

Im using my v6 fuel pump. If he had a TBI, yes it needs to be changed, if not, he is fine, but upgrading will be good for piece of mine, I plan on doing it myself.

 

If you can get the money, I personally suggest the LS1 engine for the HP, and the LS1 version T56 (6 speed manual transmission) for the mileage. (Should get high 20's easily on trips). The 6th gear is considered "double overdrive," and there is no 4-speed auto or 5-speed manual that can touch its efficiency on the highway.

If you can't afford the $8-$10K that it's gonna take for that, go for the LT1 and LT1 version T56. Probably less then 1/2 the cost of the LS1 swap, and yet only slightly more money than the L98 swap. And again, you get that efficient 6th gear.

If money becomes the determining factor, then the L98 will let you cut the most corners for the short term. Easiest install, least amount of work, lowest price for the engine itself. You could have fun with the L98, mod it in the future, and still get respectable HP with it. Later on when you have more money, you can trade up to something stronger. Start out with a 5 speed to keep costs low, and then get an LS1 6 speed when you can afford to.

The LT1 and LS1 engines are both substantially stronger in their stock form than the L98. Both of these engines were underrated by GM in the F-bodies so as not to make the Corvette look bad. The reality is that they made the same power in the F-bodies as they did in the 'Vettes, and even the 'Vettes were slightly underrated.

L98 stock = 240ish HP @ 4400 rpm, 345 torque at 3200 rpm
LT1 stock = 300ish HP @ 5200 rpm, 330 torque at 2400 rpm
LS1 stock = 350ish HP @ 5200 rpm, 345 torque at 4400 rpm

Stock for stock, the L98 is obviously at the low end, and the LS1 is the biggest/baddest/best platform from which to make power. However, you get what you pay for - it's all going to come down to what you can afford. Just so you know, there is nothing at all WRONG with an L98 engine if you just plan on cruising around the streets, if you are on a tight budget. ANY of these engines can be made pretty powerful. You can take the flywheel rating for each of the engines, multiply it by 125% to 140%, and that is what you can get close to for a REAR WHEEL rating with bolt-on mods, strong head & cam package, and good tuning (without going forced induction or nitrous). You will have a little more fun with the L98 or LT1 are low speeds though, as their power bands are a bit lower than the LS1; The LS1 pulls much harder up top. If money really isn't the issue, go with the LS6; it is a slightly better version of the LS1, with a better flowing block and heads

Now, as to gas mileage, you are going to want the 6 speed, like I mentioned. The LS1 T56 will bolt up to an LS1 or an L98, but NOT an LT1. The LT1 is a unique animal in that one regard. Another thing to consider however, is engine weight. The LT1 is slightly lighter than the L98 from what I am told, but the LS1 is at least 150 pounds lighter than that; It is made out of a completely aluminum block, and was specifically designed to be more gas efficient than the L98 or the LT1. For your goals (mileage and HP) the LS1 is the best overall option. If you do go with an LS1, the 2001 and later versions have a few early design flaws improved, and a slightly higher power rating from the LS6 (Z06) intake and torquier cam.

Hope this helps you out.

 

That would be very incorrect, if the trans bolt to an L98, it bolts to the LT1, if not you can go around the boards and tell everyone with a factory T56 from a LT1 car bolted to their L98 they arent allowed to do it cause it doesnt work and they have to remove it right now, and you better go back in time and yell at my LT1 cause i had a factory T5 bolted to it.

 

I don't know 100% cause I haven't played with an LT1 personally, however:

I know that the T56 from an LS1 will directly bolt up to an L98, minus one hole.

I know that there have been NUMEROUS discussions on LS1tech.com about the differences between the T56 from an LT1 car and the T56 from an LS1 car. The two are NOT interchangeable. Their are several differences that prevent 4th gen cars from swapping the two types.

So, logic deduction told me that if the LS1 WOULD bolt up, that the LT1 would NOT.

However, if what you say is true............... then perhaps the L98 is capable of accepting either of these 2 tranny variations, despite the 4th gens not being able to.

 

You are correct in that a LS1 T56 with bellhousing will bolt up to an L98, however it will also bolt to an LT1, what is NOT interchangable is a LS1 trans on an LT1 bellhousing or vice versa, as they have different trans to bellhousing patterns, however im still not sure if the clutch will work easily using an LS1 trans with a gen 1/2 sbc, but i've definetly also bolted one to the back of a 305 or LT1 block, dont remember which it was long ago.

Just about everyone you see on these boards with a T56 is running the LT1 variant.

 

Cool, thanks for the clarification.