I'm getting real close to starting the swap in the Firebird and just curious about a couple of things.

I can get my hands on an LT1 and tranny, but something I was thinking about after reading a couple of things.

The L98 option that was in the Iroc, GTA, and Corvette is basically the same engine except the cam/intake/heads as an LT1, am I correct in this? Plus I know the heads on the 86+ L98 in the Vette are aluminum.

Also what was the HP rating of the LT1's in the Z28/Trans Am pure stock, the HP rating of the L98 in the Z28/Trans Am and the one in the Vette, and would I be better off in going with it vs the L98 350.

And last, would the T56 bolt up to the older model L98 or would it just be best to go with a TKO in the car.

I know there are some other things about swapping the LT1 into the 3rd gen such as wiring mating of the 3rd gen harness to the 4th gen LT1 harness, but with the L98 as long as I got the engine harness and the computer, it should mate up just fine to the existing wiring in the car under the dash for the V6, am I also correct in this?

Thanks for the help.

Didn't mean to post this in two sections, if the mods could remove the one in the Engine Tech would be great...thanks.

 

LT1 hp was 275. The L98 in its best incarnation had 245hp.

 

LT1 Intake is good for over 5500rpm

TPI is good to about 4500rpm

both being stock

 

Wiring harness: yes.
T56 on a L98: Yes, there are a few on this board.
I'd do the LT1 over the L98. More power for only a little more work...

 

Depends on how much you know about the swap, but your basically right. The LT-1 has alot more potential than any small block with a TPI manifold on top, but LT-1 specific parts aren't nearly as cheap as Gen 1 small block parts, which do work on the L98.

 

nevermind

 

The LT1 also features reverse cooling sytem and cam driven water pump as well. Also the LT1 uses all lightweight balanced parts as well.

 

Well it depends on what he is using it for. If he is just cruising around town and not street racing (a lot) then the TPI with a few mods would be just fine since it put out 345ft/lbs of torque as opposed to the 285( I think) of the LT1. However, if he wants it to be a highway racer, the TPI will obviously die in that area and the 5500+rpm potential of the LT1 would outshine the low end torque of TPI. Also depends on how much knowledge/money you have. Gen I SBC is probably the easiest engine in the world to work on and the aftermarket is HUGE and fairly cheap for going fast(cheap being relative of course). The Gen II SBC is a bit more complicated and there are, from what I have seen, only a few heads options (LT1, LT4, and AFR) for this particular engine. So the aftermarket isn't as large as for the LT1 as it is for the TPI and isn't nearly as cheap either. So basically, it just depends on what you wanna do with the car.

 

Rememener buys the LT1 was underrated. The f-body L98 was not the same as the vette L98 so there was a considerable power difference. With the excepotiong of non power influencing differences the f-bod and vette LT1's are the same. The only real power differences come in the exhaust. Since the f-bods can't be rated the same as the vettte they got the lower rating (275 vs 300). A stock LT1 is more around 300 at the crank. Most stock M6 LT1 cars will put down between 250 and 265 at the wheels. The toruqe is also underrated. With only a few tiny mods (slightly better exhaust and intake) GM rated the LT1 SS and firehawk cars at like 305 hp. Those mods do not increase power by over 25hp alone. The only way I would go with an L98 is if I got rid of the stock intake in favor of a mini-ram, stealthram etc etc. Than the motor would be pretty much on par with a stock LT1.

 

The main reason for the swap is gas milage. I don't have the funds to put an LS1 in the car, so that's why I'm wanting to go with the LT1 or the L98. The 6-speed should help that tremendously as I hear people who are getting 27-28 MPG out of the LT1's and it should be the same with the L98. The other main reason I'm thinking about the L98 is the pain of wiring up the OBD2 system (I want a 95-96 model engine) to the existing wiring in the car.

 

Gas mileage difference is probably small, but the LT1 should be a little better. The main reason the LT1 should go into the car is.... well.... its cooler

 

Air,, I think my L98 setup is pretty cool. Well, when it gets running it will be.

 

the LT1 made 335 lb feet@ 2,400 rpm and over 300 from 1,800-5,200...the only rpm range were TPI outperformed the LT1 intake is from about 3,200-3,800 at which point the TPI was in the meat of its power...above or below that its all LT1...as far as aftermarket for them, only the head department needs some work..Trick Flow has come out with an LT1 head 190cc intake i beleive, and like said AFR has a very good performing head, so its not there arent qualiuty pieces available...any cam that will work in a GEN 1 will work in a LT1

 

Don't you mean any Gen II cam will work in a Gen I motor?

 

i knew someone with a good set of eyes would catch that.....im sure you know about the dowel pin; it can be tapped in or pulled out/cutting wheeld off...thats for using a LT1 cam in a SBC motor...now there are some guys over at camaroz28 who have used SBC cams but modified the snout in order to mount the dowel pin...im guessing they bought the cam used, becasue they cost about the same new...so any SBC cam will work in ANY SBC..

I however, dont have to worry about that dowel pin...no OPTI on this LT1 :hail: :hail: :hail:

 

I think the 93 cars had a much shorter dowel pin which allowed you to get away with a Gen I cam if need be. I am not sure though. I know the conversion to a vented opti requires a longer dowel pin.

 

1st, the tpi might make a tad higher PEAK torque than an LT1, however the average curve of the LT1 will let the LT1 mod for mod walk all over the tpi setup.

2nd. whatever this talk about TPI motor specific parts costing more than a gen 1, about the only 2 parts that are really going to be different is the water pump and distributor.
However the water pump and distributor are far far priced below what an aftermarket tpi setup would cost, and the lt1 intake will still outflow it.

3rd the LT1 has a computer that will work better and easier for most peoples setups,

4th you said you wanted a 96-96 motor and obdII which is a 96-97 thing except for cali 95's, which you get no benifit with obdII for the most part, only higher priced software for tuning.

5th Wow there arent 15 diff manufacturers for LT1 heads, gee the stock heads ported have only been known to be used in 375-450 rwhp setups NA, nah that couldnt be the reasoning behind it nope nope, AFR steps in if you're looking for something radical beyond this point, who really needs 15 choices, so long as the power potential is there.

 

yep 93-95 cars had the obd1 and non vented opti...the cam i bought for mine was a long pin cam...but i didnt have to touch it because the opti block off plate covers it all...

and actually the obd2 impalas (96) were slower then the 94-95's.....maybe ill go back to EFI...but looking at the big @ss bowtie on the intake were the thermostat should be is friggin cool lol

 

I have the L98 motor in my car, and i'm swapping it out for an LT1. True, the motor is shot, but i would be MUCH MUCH easier for me just to get a SBC longblock, plop the TPI intake on it, and be done with it. Rather than all the wiring and routing and stuff.

The L98 is an excelent truck motor, however.