I posted this outside of the LTx/LSx swap subfourm in an effort to reduce the bias towards Gen III small blocks that (quite natually) exists there.

It's been a good 230,000 miles, but I'm ready to ditch the antiquated LB9 and move on to bigger and better things. I've been researching for a few months and the general consensus seems to be the following:

Gen III: good
Gen I: bad

Ok, that might be a little too simplistic. But I'm looking for horsepower, along with fuel economy and driveability: The quintessential high performance daily driver. Ideally, I'd fly a unicorn to work and skip traffic altogether. But some things are just out of the realm of reality. The best combination of horsepower, economy, and driveability I hear can be had from the Gen III series of motors, and I really dont doubt it, but what is it about this magic combination of parts that allows one to make 350 horsepower and still manage to get 28mpg?

My first guess is the PCM. Most discussions on Gen I vs. Gen III motors end with "If you want the most horsepower for your dollar, go with Gen I; If you want the same horsepower and you want to be able to drive it on the street and get some semblance of gas mileage, get a Gen III." Most of the time the comparison is between a carbureted Gen I motor and a fuel injected Gen III motor, and is perfectly sensible. But what about a fuel injected Gen I?

Either way I go, I'm most likely going with megasquirt for engine management. So how would a mild-cam Gen I block with, say, a stealthram intake and vortec heads compare with a stock LS1, if they both used the same engine management system? Efficiency is a function of fuel and spark control, and combustion chamber characteristics; knock the first two out of the way and where do the Gen III blocks really shine? There's a whole lot one could do to change combustion chamber characteristics in a Gen I block before hitting the price of the average Gen III swap. And if you could achieve the same power levels while maintaining economy and driveability, is there still a reason to swap?

Obviously the Gen III engines are extremely popular, and I'd kill to have one myself. But, can a Gen I engine running a modern fuel injection system be built up to the same power, economy, and driveability levels as the average Gen III? If it could, it would most certainly be cheaper. Not as cool, maybe, but for me, money will ultimately be the deciding factor.

 

It's all in the heads, LS1 heads are pretty much the most advanced cylinder head out there right now. Vortecs don't hold a candle to what they offer. If I were you I would go for a 5.3 or 6.0 truck motor. Much cheaper than the LS1 cousin and you'll either make more power than the 5.7 with the 6.0 or get better fuel economy with the 5.3, take your pick. The only downside is the iron block, and you never mentioned weight as being a priority. You'll still need a f-body oil pan, accesories and intake to make it work. If you play your cards right you can pick all that stuff up individually and have way less than 2000$ in your whole LSx setup.

The only downside to the LS family of engines is that you'll have to use a LS trans or get an adapter to use your trans....I just highly doubt it would hold up. If your stock trans is wore out it's a moot point, just get a trans for either combo.

 

The LQ4 has been the engine I've been looking into the most. I just can't see any way to reasonably do it for $2000. Here's what I think would be a reasonable price breakdown for an LQ4 swap:

LQ4 Engine w/ harness, pcm, and accys. ($1400)

I can't get a straight answer on whether or not truck accessores will work, so they'll likely have to be swapped out for f-body accessories.
F-body accessories ($???)
F-body oil pan ($150)
Wiring harness work ($50 probably, in parts if you do it yourself)

I'm going to do tuning myself, it's the way I am. So:
Megasquirt ($350)
LC-1 Wideband O2 sensor and controller ($200)

Intake ($350 for used LS6 intake, truck intake won't work with f-body accys.)
Fuel pump / regulator / fittings ($300 is my guess)
Custom y-pipe using stock manifolds ($200 in materials perhaps?)
Motor mount adapters and transmission crossmember ($200)
Transmission ($500-800 used, or adapter kit to mount up 700R4, plus some way to mount a kick-down cable to LSx throttle body)
Plus a lot of little things that never get included in these cost tallys. ($???)

That's the bare minimum, stock manifolds, no cam change, probably running stock, 310-325 hp. Add headers, cam, intake, etc, and you're REALLY talking money. The Gen III aftermarket is expensive..

Now, you could sell off the stuff you didn't use from the LQ4 engine to recoup some of the costs, but LS1 accessories are more valuable than truck accessories, so it's not going to be 100%. All in all, there's going to be quite a bit more than $2000 in an LQ4 swap.. Unless you get some really killer deals

 

The word that caught my attention was "drivability". Going no further than this, I would reccomend finding a low mileage gen 3 motor along with its corresponding electronics and simply plopping it in. Assuming all things are in order with this new motor along with the rest of your driveline, what this affords you is a motor with all of the tuning issues taken care of, as well as a proven motor combination that is fully assembled and ready to drop in. Now, you mentioned that you will probably be running a megasquirt system, and in doing so you will be involving yourself in tuning and wiring which obviously takes away from the "ready to go" situation of the gen 3 motor. If you are willing to dive into that, then building a gen 1 motor to suit your desired power level becomes a more attractive option.

 

Gen 1 you can make that 350hp very easy for alot less money. The down side is you need to drive like an old lady inorder to keep gas mileage in the high teens.

Gen 2/3 can make you that 350hp but upgrades cost alot more. You also have to consider computer work and chips ect. Thing is you can drive pretty hard and still get 24mpg easy.

 

Carbureted or fuel injected? I'm a newbie, I don't build engines for a living, and I've never even seen under the valve covers of an LS1, but I just can't fathom seeing such a huge drop in economy among two properly tuned, fuel injected engines with similar cams and equal displacement. LS1 heads are obviously lightyears ahead of the infamous vortechs, but to go from high-teens to 28mpg (which is the number that seems to be common among stock LS1's), just seems like an astronomical increase in efficiency. Plus, there's tons of heads out there for Gen I's. If that's the only issue, I think one could get ahold of a better set without going over the average budget of a Gen III swap..

But if I new jack s*** about head design and maximizing engine efficiency, I'd already have an answer. I'm clueless, however. And I haven't found any good answers yet, hence the thread

 

going from your previous post, I furtherly reccomend a gen 3 swap. If you build a gen 1, you will need to spend time and money either building it or getting it built, dropping it in, and getting it tuned.. and you aren't guaranteed to have all the bugs worked out the first time. Getting a stock gen 3, more will be involved with installing it, but you completely sidestep building and tuning which translates to you enjoying the car sooner. Take it from my own personal experience; I went from a 3.1 to a mild tpi 350, and issues have presented themselves along the way. It's not that I dislike wrenching on the car, but what it comes down to is less time actually enjoying the car. That's what it's all about, isn't it?

 

The way it boils down for me is:

Gen 1 - simple, cheap, easy. Everybody and there dog knows how they work, how to tune it, and where to get parts. Parts are cheap and plentiful to make all kinds of various combos. Simple and cheap is what works for me.

Gen 3 - no doubt about it, superior in every way shape and form. Finding one is harder, they aren't lying in bone piles left right and center. More importantly, the aftermarket is like 4x the price to soup it up. Also they are more complicated (i'm talking FI vs carb here), and less people know how to tune them. Lets say you're desperately trying to tweak it, less people are out there with a lot of knowledge to help you, compared to guys who know how to tune a holley on a chev 350. Right? right.

If you want cheap fast easy now, SBC1, if you plan to drive it long enough to use the mileage to offset the initial buy in price, and have the skills and time to learn how it works and how to tune it, and are into the whole cutting edge technology stuff, give'r.
I didn't have the upfront cash to go to a SBCIII, so I figured i'd learn from the beginning, and work my way forward in technology, but learn the old stuff first. So I have an SBC1.

 

The Iron block is actually an upside of having a 6.0. It's not the lightest but it's very strong which is good when the time comes to start building a serious motor. And like everyone else is saying if you're looking for streetable power the LSX motors are going to be your best bet. Honestly the swap isn't cheap but no engine swap that will perform similar will be cheap. People nickel and dime an LSX swap when they talk about it but then when they say to use a Gen 1 SBC they just talk about how much for a motor and that's it.

 

while we could start a flame war on this statement all day long, I'll try and keep it simple. as far as long block goes, there is very little difference at all between a gen 1 and gen 2 engine platform, and no difference that makes one better for power than the other. now, carb/LT1/LT4/TPI/whatever is another story, but can be adapted to either longblock. this means the real issue is still gen 3 vs gen 1. and like he said..... economy. over the long run, it balances out either way. you'll pay up on the front end for the intial cost of an LSx swap, and for go-fast parts. but they make big power with the same mods due to a great cylinder head design. the gen 1's are easy to obtain and parts are cheaper. flat out. but they don't give you AS good of gas savings and reliability/longevity that the gen 3's do. not that the gen 1's die quickly, quite the contrary. but gen 3's seem to keep the pep in their step a lot longer and it's easier to maintain them.... cam swaps can be done w/o removing the lifters or intake, and intake swaps are still a short ordeal as well. and let's not forget, these cars much more readily accept the gen 1/2engines than the gen 3's, though parts to swap the gen 3 in areeasily had, they still need to be factored into cost, plus a little home fab work running wires or making the A/c work. not hard, but still more work then a gen 1. but honestly, it's all subjective. I have a gen 1, but I'll recommend either based on 1 thing:

when can your afford to pay the piper?

if the answer is up front, go gen 3, enjoy it, and never look back. you'll love it, especially if you snag a 6-speed. fuel injection is dead reliable mostly, and easily compensates for atmosphere and mods.

if the answer is over time, then go gen 1, build a bad *** gen1 and then build your WHOLE dang car for the same price as a 500hp LSx ENGINE, including suspension, chassis, brakes and trans. just be prepared, even if you're running fuel injection, to have to work on it a little more, and put in the little extra time to get it just right.

I like my antiquated 750 edelbrock carb and MSD HEI pro-bilet dizzy. F*** opti-spark, and F*** separate expensive coils. does it suck gas like a $20 bj? YES. but if keep my foot out of it, I get about 15-18mpg. and i can still add nitrous and make it faster if i want. and most of all, I did at least 80% of it completely on my own, by reading stuff here, in books, elsewhere on the internet, talking to people who know a lot more than me, and generally schooling myself over the last 5 years. I have the car the last 3, and I can honestly say I might change a few things, it wouldn't be this motor. I just would have built it sooner. hindsight is 20-20. can you do that with a gen 3? yes. it's all in how much it's worth to ya. either way, good luck bro, you have the best resource there is right here.

 

the thing is an ls series motor will give you more hp per buck than a gen 1 and can make monstrous cams more streetable than ever while retaining that efficiency in terms of gas mileage. nothing like a 400+rwhp monster that idles and drives like granmas lincoln

 

Whats wrong with a fuel injected gen I? with after market engine management, you can go sequential fuel injected like what the gen III's have on a gen I motor.

 

Thanks flyitlikustolit for the great post, pretty much seems to fall in line with what I've slowly been learning. I just wish the Gen III aftermarket wasn't so outlandishly expensive Otherwise the decision on which block to build off of would be pretty easy.

Sequential injection on a Gen I would be nice, but accurate measurement of cam position would be a must for it to work right. Is there an easy way to put a cam position sensor on a Gen I block?

 

Sequential injection on a Gen I would be nice, but accurate measurement of cam position would be a must for it to work right. Is there an easy way to put a cam position sensor on a Gen I block?[/QUOTE]

https://www.thirdgen.org/forums/tpi/...-opinions.html

 

totally agree, bnoble. good luck. let us know what you decide to go with.

 

There is a distributor out there that has two sensors, the extra for the cam so you can run SFI. A dual-sync dist.

 

I would go with the Gen III.

the difference between my 88 trans am w/ the 190hp 305 v.s. my 05 GTO w/ the 400hp 364 (LS2) is astounding.

with basic light boltons I have a 450hp monster, that can nail 27mpg on the freeway all day long.

v.s. the trans am, that got smoked by my girlfriends mercury mariner SUV, and would be lucky to score 18mpg on the freeway.

LS sounds better, goes better, and scream down low and up top. I wouldn't trade my LS2 for anything less than a LS7.

plus now LS7 intakes are being adapted to LS2's and now you can easily have 500+ whp, NA Gen III/IV motors that are still considered kinda mild, since you haven't added any forced induction, or any kind of power adding injection.

 

Just decide that your wallet can stand, make a decision and go. What makes you smile.....ok spend it.