L98-lt1

[noel]

I am kicking around the idea of upgrading my 91 L98 to a LT1 but it sounds like trying to change stuff on the motor might be harder then its worth so if i had a complete LT1 what else on the 91 would I have to change I dont know anything about vettes my first 1. am still not sure about all the letters and #,models &stuff
thanx noel. Ill try to catch up asap

 

[Tuna]

Very little of the L98 is compatible with the LT1 so 'upgrading' your L98 to an LT1 is probalby not the smart thing to do. The LT1 is a "Gen II" configuration and not much is compatible with the L98.

There is still plenty you can do to the L98 to make it better without trying to convert it to an LT1.

With that said, what do you really want out of you car?

 

[Vettefan87]

About the most you can do is put a LT1 intake on your L98, but it involves some pretty extensive modifications, if you modify the intake yourself. I think Mad-Mic, modded one to go on his car, you might want to PM him if you are interested in something like this.

 

[noel]

I thought that was the case thats why i was thinking about changeing the whole motor for a LT1 but need to know what else i need to change like wiring,computer,ac, cables and other stuff if to much Ill just say to heck with it
on mustangs that have speed denseity you cant do any mods till you change to mas is this also true on vettes????
noel

 

[Vettefan87]

If you want a LT motor, it would probably be cheaper to sell your vette and upgrade to a different vette.

 

[Edmond]

If you want a LT motor, it would probably be cheaper to sell your vette and upgrade to a different vette.

With the low prices of 'Vette's today, that would be the thing to do.

 

[jeffyc]

the L98 is not a slouch
the difference bettween the L98 and the lt1 is that the L98 has its power band down lower in the rpm range

some one correct me if i am wrong but the lt1 vettes dont run away form a l98 vette ?
they get a better trap speed (LT1) and got like a car length or 2 the L98

 

[PLRX]

I agree, I would not race a L98 in the quarter mile for money. :ugh

For fun? yes

 

[Vettefan87]

Me personally I have not drove a LT1 vette, but dont they after about a 100 pull a lot harder then our L98 cars?

 

[Edmond]

the L98 is not a slouch
the difference bettween the L98 and the lt1 is that the L98 has its power band down lower in the rpm range

some one correct me if i am wrong but the lt1 vettes dont run away form a l98 vette ?
they get a better trap speed (LT1) and got like a car length or 2 the L98

Very true, but in an "impromptu" race, it's as even as it could be. I wouldn't be surprised if the L98 could beat the LT1 stoplight to stoplight.

 

[jeffyc]

see noel the L98 is not a second class engine its just different then the LT's
and has different charateristics then the LT's
the big advantage of a L98 over the LT's is the are a gen 1 small block
and the gen on sb and alot of companys have put alot of $$$ in making HP with the gen 1's
when i was out shoping for my vette i didnt care about if it was an LT or a L98
i wanted a 91 or newer (i looked at alot of junk and i could write a whole new thread about the sellers of some of them vettes. i still get a laugh) i wanted the newer body style and was more interested in how good of shape the care is in and how it was maintained (didnt want any young guys to have owned it as a previous owner)

 

[noel]

I like my 91 & doubt if I could trade for less then redo motor with upgrades was talking to some guy he said go to strocker while doing rebuild 383 0r 388 something& the more i think about it the better it sounds but trying to figure out what to do about intake ???? seems like the only easy way is bigger runners wanted that hsr system but wont work with my heads

noel

 

[Edmond]

I like my 91 & doubt if I could trade for less then redo motor with upgrades was talking to some guy he said go to strocker while doing rebuild 383 0r 388 something& the more i think about it the better it sounds but trying to figure out what to do about intake ???? seems like the only easy way is bigger runners wanted that hsr system but wont work with my heads

noel

Noel,

There are plenty of high flow TPI intakes out there. Most notably are probably:

TPIS Big Mouth intake
Edelbrock high flow TPI intake

The original TPI intake was designed for the 305 motor because Chevy considered discontinuing the 350 in favor of the 305 but stayed with the 350 at the last moment. They did not have time or the desire (read money) to re-design the intake for a 350 so they kept the 305 intake on there.

You will need large tube runners.

I read in Corvette Fever that had a nice comment on the TPI. No, the TPI wasn't designed to be a high rev setup but it produces great amounts of low end torque. Line L98 and LT1 at the stoplight, anything can happen.

 

[noel]

I wonder if a person could get by with just runners & porting base & plenum ro if you would have to buy one or other or both to be good
I am going to get runners though am leaning to wards edelbrock because of price???
noel

 

[Edmond]

I wonder if a person could get by with just runners & porting base & plenum ro if you would have to buy one or other or both to be good
I am going to get runners though am leaning to wards edelbrock because of price???
noel

Noel,

I was told by a reliable source that the TPIS unit was made for them by Edelbrock. I don't know if that's 100% true but I think it could be.

The stock runners are quite small, IMO.

I would also spend another $200 for 1.6 roller rockers for some more lift and horsepower.

Check out www.thirdgen.org for some good deals. There is a large TPI following there.

 

[noel]

I was wondering if 1.6 rockers would be just as good as a slightly bigger cam I hate all that tech stuff it hurts my head

noel

 

[Edmond]

I was wondering if 1.6 rockers would be just as good as a slightly bigger cam I hate all that tech stuff it hurts my head

noel

It depends on the cam. The cam specs that you read are usually figured with a 1.5 rocker ratio. Take the cam lift number and divide it by 1.5. Then multiply it by 1.6 and that's the lift you would have with the same cam but with 1.6 rockers. Throw in the full roller (roller fulcrum and roller tipped) and you have a smoother operating rocker.