Can you all teach this ol dog a bit

[tphsmith]

what is the diffrence between the L98 and the LT1, what years diffrence and what engine modification diffrence. come on this is my first time and first post. why all the questions? well I want to know as much as i can about the TPI engines and where else is the best place to learn?. from you guys who deal with them everyday. the guys who have the experience. thanks in advance

[topendlt1]

My brother has a 87 IrocZ 25th Ann. with the L98 5.7L Tuned Port Injection.
Its a very nice car.

Power wise, the L98 is impressive IMO. In stock form, the 91' and 92' 1LE L98's were perty fast.

He has K&N's, a Chip, with a nice exhaust, so...
Stock I think my bro's car is pushin around 220 hp/ around 340 Torque... flywheel. ( Somewhere in there )

His 0-60 time is around a 6.5 I believe, but everytime I tell him that he argues with me, telling me mine is only a little faster. ( 95 Z28 )

They are very upgradeable cars, and they have frames, not unibodies like my car I believe.

There not my bag of chips, but a nice 3rd Gen is Ok in my book.

[tphsmith]

thanks, anyone else have feed on this issue of L98 compared to LT1

[CamTom12]

L98 is old school small block Chevy, just with a different intake style

LT1 is old school small block Chevy, just with cool things like new style intake, new distributor (opti-crap), reverse-flow cooling, better heads, etc.

Both are great motors and upgradable :thumbsup:

[five7kid]

3rd gens are unibodies with front & rear subframes. Subframe connectors are one of the first upgrades one should consider on one.

L98 is, as stated, a tuned port injection (TPI) engine. It was designed for low end, seat-of-the-pants torque - made it "feel" faster than it really was. Upgrades are available but expensive. The port runners are long and narrow to promote that low end torque. To get more power, you need to replace those runners with shorter, fatter ones, available only from the aftermarket. Then the next restrictions are the intake base & the inlet plenum. You can either port the base or get an aftermarket unit, porting the plenum is usually sufficient. You're only going to get about 400 hp out of one with those mods, the next step is to replace the entire intake system, either with a Super Ram or Miniram. They run about $2k.

Now, this Miniram thing is pretty interesting. Looks a whole lot like an LT1 intake. . .

[Chris 96 WS6]

Physical differences:

LT1's have reverse flow cooling, and a cam-gear driven water pump. Due to this and the front mount opti-spark distributor, the LT1 block's front timing cover area is different, therefore the blocks are not interchangeable with standard small blocks. Well, they can be but you'd have to use an LT1 timing cover and plug the opti and water pump drive holes. SBC timing cover won't fit.

The Intake is dry...no coolant goes through it like in a small block intake manifold. There is a crossover tube mounted to the backs of the heads that allows coolant to move from one side of the block to the other instead. The heads are also designed differently and the coolant holes in the heads and block are different than an SBC.

That's if for physical differences other than the shapes of the runners and chambers. The LT1 has a much shorter intake runner length, which helps build HP. The L98's ultra long runners build gobs of low end torque but really choke the motor above 4000 rpm.