Basicly, which one is better dollar for dollar. I'm going to be removing the v-6 in my car now for a real engine but I'm not sure between the two. I'm wanting to use a t-56, so I was leaning toward the LT1 since I could get the two together for less than an L98 + T-56. I'm wanting everything to be as new as possible, so I'm considereding buying a new L98 shortblock or doing a rebuild. The local junkyard said it was $2k for an L98 with all accessories, does this sound right, or should I keep looking? Thanks, Joe

 

No 2k does not sound right, I know that thirdgenresource.com sells RUNNING TPI COMPLETE motor setups for like 1250$ and the COMPLETE LT1 setup for 1500$.....

http://www.thirdgenresource.com/inc/...l?v=1&pid=1550

LT1 swap will require more modifications....the T56 is going to require modifications either way.

 

I say go with the L98. I read an article about a year ago that said to put a true LT1 motor in you'd have to bang out the frame and the firewall to make it fit. But there is also another option, if you want the LT1 without all the hassel, there is a member here who can take a LT1 intake and modify it to fit on a standard small block. I think either option would be worth the time and money. But I'm kind of partial to my 355ci 380 hp TPI

 

Have you actually had the motor dynoed? I would have my doubts on a 380 hp TPI. Even with aftermarket parts, the high end is restricted enough that you rarely see a tpi with that much power naturally aspirated. You see them with killer torque all the time, but thats quite a bit of power for something that doesnt breath above 5000 rpm.

Ben

 

I guess I should have mentioned the 355 was dynoed 350 hp at 4600 RPM's when I had it built by Dreamchaser Racing Engines here in Amarillo. When it was, It had a standard carb with minimal fuel pressure and was set at 8* advance. Since then, I've got SLP Runners, Edelbrock Hi-Flow Intake, Hypertech Performance Chip (Not Worth The Money), Hypertech 53,000v Cap, Coil, and Rotor Kit, a fuel pressure regulator to boost fuel pressure, and have advanced the timing 12* at 2500 RPMs. So it really is an estimate, but I wouldn't have any doubt if it was this or higher. (Also Note - This at the flywheel, the motor was not in the car when dynoed)

 

Well, it does sound like that power band is in the rpm range that tpi makes its power so I guess it could very well be possible, but it just doesnt seem like I see people making that much out of tpi's very often.

Ben

 

Well, for my situation, most of the power is in the block that I paid about $2,500 for. I wish I could tell you what this guy put in, but I'm not a motor savvy person. I couldn't tell you the duration or what brand of anything is on it. I am pretty knowledgable about the rest of the engine, but I'm limited. And you are right about the torque, she's beast, I went through the first tranny rebuild in about 6 months, and the next in under a week. So far the one I have now is holding up. I love the power.

 

In your case I would go with an LT1, more power right from the start. Better fuel economy as well.

 

The HP per $ depends on SEVERAL factors.

To start of with, the LT1 was rated at @ 275HP, the L98 @ 245 HP. So the LT1 has a 30HP edge here.

Now...will you be doing the LT1 swap yourself? If YOU are doing the labor, the swap cost to the LT1 can pretty much be justified, so let's call the swap to either a wash...


Now, are you dropping the engine in stock or modding it? LT1 hop up parts are more expensive, so that's a factor too.

The advantage for the LT1 is the fact that the stock cylinder heads flow pretty good numbers from the get go, and even more with a decent clean up job. Add a good cam, headers, and look into LT1 edit and you can make some good power.


Now as for the L98, why not just score a complete TPI system and wiring harness and build the engine itself like you want it from the beginning?

I'm still deciding on whether or not I'm going with a 400 or 383 roller based TPI motor, but I should know in the next few months, I'm still debating the cost on converting the 400 to a roller cam, vs. the added power the 400 will have over the 383 and whether or not it's worth it in the long run.

True, the TPI setup does not make power as high up in the RPM range as a LT1, but IF you gear your build up towards the mid-range where the TPI makes power, it's a different ballgame.

$ for $, since you DON'T currently have TPI, if it were ME, and strictly from a $ vs. power standpoint, I'd score a TPI wiring harness, then just buy the Stealth Ram setup.

Build a stout 400 / 383 based engine to go underneath it, and you're past stock LT1 AND LS1 power levels with some decent tuning.

I've personally built and dyno'd several 383 and 400 based engines, and for the money, the 400 is hard to beat.

A MILD 400 with a decent set of heads, a good cam selection, and good exhaust will easily make 400-450 HP and equal or most likely BETTER that in torque output.

So with a manual tranny, and say 15 percent drivetrain loss, a 425 HP 400 will put @ 360HP to the rear wheels. TO put that in perspective, stock LS1 cars w/ M6 dyno around 300-320 HP to the rear wheels....and the kicker is that the 400 will make MORE torque across a flatter power band than the LS1 without major mods.


In the end, you pay your money and take your chances.


HTH

 

Thanks for the detailed reply, ctandc. I would love to do what you described, unfortunatly our wonderful California smog laws prevent me from doing most of it. I had considered a 400 but after the swap I have to take it the smog referee to get it approved, and I'm afraid they may pull the casting numbers off the block. At that point it'd be my ***.
So...I'm going to have to use an L98 or newer engine, and nothing bigger than 350. I'd like to be able to mod the engine, I'm still debating whether I'm going to do it before or after the swap. My concern is that certain mods to the LT1 might not fit in our engine bay. Specificallyl, I was told that the S/C kits for the LT1s would have some clearance issues. And again, I could only use the ones with an EO number (which are few and far between).
I think the best long term solution would be to build/buy an L98 with forged internals. I just don't know if it is the most cost effective way to get where I'm going. I've decided to go back to school, which will put a cap on my income, so I don't want to have to pay out for this swap for the next 2 years.

Thanks for all the ideas and advice guys!

 

LT1. I was going to use the 385 fastburn(with the mini ram III intake) and was able to find a 95 impala ss lt1(complete for $950 on ebay). And also found that almost all the parts to make the LT1 work from the 95 impala series worked as well.

 

I don't think that is the case. I have heard that you have to change the motor mounts. I know you do with the LS1. www.thunderracing.com sells the LS1 motor mounts for third gens. But I don't think you have to bang out anything. I have heard that it is a pretty straight up swap. Except for the wiring and computer part.

I have never heard of banging out anything for an LT1 swap.

 

As far as I know the LT1 is pretty much a drop in. It uses the same mounts, etc. Pretty much all of the changeover parts are also needed for an L98 (ECM, radiator, gauges, etc.) swap from a v-6 anyway. So as far as I'm concerned it's the same amount of effort involved. I'm not really worried about all the wiring. I'd definently feel more comfortable doing a swap with an EFI engine than a carbed one. I dunno, maybe it's from growing up in the computer age, but I feel better about playing with wires and ECMs than carbs and mechanical fuel pumps.

Bluepastu, did you find the car locally, or did you have to have the parts shipped to you? My biggest concern in that shipping is going to kill me. Most of the ebay engines I've seen have $500+ in shipping fees. So if the engine (L98) cost $1200, plus shipping, I've only saved $300 over the local cost (from auto dismantler) and now if there's a problem (cracked block or head, missing parts, etc.) I have to deal with someone 2000 miles away, and if I have to send the engine back, another $500 in shipping. Are my fears misplaced? Thanks, Joe

 

Ok, well with a little more readiing, I think you're right about the LT1, Maybe it was the LS1 I was thinking of, sorry about that. The LT1 does fit and uses the same motor mounts...

 

BY FAR the biggest pain with the LT1 is going to be the wiring. You simply CANNOT swap in a LS1 or LT1 engine into an older vehicle without installing the COMPLETE GM HARNESS if you want EVERYTHING ( emission , PCM etc ) to perform as GM intended.


People will know post how great their Painless or other plug n play harness is / was, but I Can tell ya, the CLOSEST I've seen yet is a Howell harness, and even that had a couple of issues and it cost a pretty penny.

Go to Speartech's site.......they swapped a LS1 into a 3rd gen and EVEN THEY USED the GM HARNESS, even though they sell a harness for that swap....imagine that

TPI swap into a carbed vehicle is a CAKEWALK compared the LT1 wiring.


YMMV

 

i just got an l98 today with intake and heads for $100, 165k miles on it, gonna convert to 383 and LT1 though.

 

I scored a LT1 short block for free Ofcourse, it needs a rebuild, a light honing, rings, and bearings I'm told. But I'll probably do the whole rotating assembly.

So, I will eventually be going LT1, but I want to do some major mods to the short block and heads(when I find a set I want) over the next two years. Then just have the motor waiting in the wings for when I gather everything I need.

 

*If* you have a 90-92 V6 car the TPI motor will require no wiring changes if you get a complete engine harness from a 90-92 tpi car, the chassis wiring is the same entirely between the V6 and TPI cars it would be a bolt in plug in deal, radiator is also the same on them.

As far as modifying a LT1 vs. TPI motor and $ per part, some like to say the TPI mods are cheaper than the LT1, like what a set of heads ? Yes you can get a set of nice aluminum heads that will probably match a ported set of LT1 head flow for around $1000 assembled, vs $1600 for a nice set of LT1 heads, ok so its got a $600 jump, now you dont have to do jack to get the LT1 intake to outflow pretty much every smog legal TPI intake you'll spend $1400 for a superram plenum base and runners, so that would be a $800 point to the LT1's side, or just $900 on runners for the tpi and a baseplate, still putting the LT1 ahead by $300 after the top end is something decent. After this the only real differences are the opti vs. distributor and water pump, negligible.

Then comes tuning, burning chips, trying to get the tpi engine you build installed and running right in the first place, vs. flash programming for the LT1, im quite sure the equipment to flash the LT1 pcm is cheaper than a prom burner, eraser, and the software for the tpi ecm. Even if not the LT1 will be easier to tune with its MAF.

The LT1 does bolt right in, some K member massaging is required on some of the installs, every car is different, and its a piece that unbolts from the car should you for some reason decide to return it to a showroom stock car its not like your cutting out a piece of the framerail.

Anything else for the LT1 vs. TPI is pretty much the same parts so good luck saying the LT1 costs more, that may hold true for the LS1 right now, but for $ / HP the LT1 is typically going to come out on top. The entire bottom end and valvetrain is late model Gen 1 parts, flywheel just the same, etc, headers you use 3rd gen parts.

As far as the idea of a supercharger goes, i know of 3 setups that would fit into a 3rd gen with an LT1, 1 of them probably wont be as easy as bolting a 3rd gen kit right in, but 1 will fit much better and be the easiest thing around to work on, not to mention the LT1 being far easier to work on and leaving you with lots more room with or without the emissions equipment.

The list goes on and on and on and on. LT1 > TPI motor.

 

I swapped out 305 TBI and put in a L98 TPI, I am now swapping in and LT1. For me the LT1 has been a tad more expensive as far as freshening it up. I didn't want to use old stuff that might go out so I put new gaskets, water pump etc. The LT1 was more expensive in these areas, such as water pump, o2 sensors, opti vs cap n rotor type stuff. If you are going to use the engine as is these costs are not a factor. Although the total is only a few hundred more, if your budget is tight this is money you can use elsewhere like for the stuff you never thought you would need but can't possibly do without.
I do agree with Z28***** as far as moddifications go. The L98 and LT1 both have strong and weak points cost wise that for the most part balance out.

 

I have been researching CA smog laws a bit, as I will very likely be moving to San Diego in the next couple of years.

My understanding is that you can use ANY engine, as long as it was a factory option for your vehicle at some point in time. So, this means you can basically use any SBC, TPI, LTI, or LS1.

As far as I know, the LT1 will fit in fine. I know an LS1 will, and I believe the LT1 to physically take less space in the bay.

As far as a 383 or 400, if they see a different block number, you are right - it's your ***! However, you could use the same block, and build up a 383 stroker (TPI or LT1, either way) and the smog ***** will not be able to tell!!! You are NOT limited to a 350, only a BLOCK that was a stock 350 made for a camaro.

As far as the S/C, I know the Prochargers are 50 state legal! I'd call and ask about clearance with an LT1 package if that's the route you are looking at, otherwise you shouldn't have any problems that I know of with the L98 and a Procharger blower.

Personally, I think your main area of research to decide which engine to choose is to look at the available mods for each that have E.O. #s. Some of the best L98 mods don't have any E.O.'s for CA (like the TPIS mini-ram intake), not sure about the LT1 mods - I haven't researched those.

I'm putting a CA emmissions-compliant swap with an LS1 into my 89 Formula right now. I'll be rebuilding the original L98 TPI engine into a 383 stroker and dropping that into another future f-body project car at some point, again keeping it CA compliant.