Okay, here's the deal, I have a '92 RS that has a 305 TBI. The computer has timing issues on it, so I figured I should stop wasting money on that motor and buy a friends LB9 motor and 700R4 swap. He has the whole swap, the harness, everything needed and it's got 70,000 adult driven miles on it. He's asking $1,500. He did tell me the heads were just redone and the valve seals, and seems to think that it is making 230hp.

I doubt that, he didn't do anything too drastic.

My question is...

190hp sounds really whimpy... I'm affraid that after the swap is in my car, it will be hardly enough to beat a Honda Civic. Can anyone here tell me what an LB9 can do? How fast is one? Does it feel slow?

I have thought about mods, maybe headers, intake runners, cold air intake, a chip... I have a budget of about $1,500 for mods. Any suggestions?

Thanks!

 

Lots of ppl think their weak sauce but i think its pretty fast car my stock with a cut off exhaust stomped a 07 v6 tiburon with mods that was 6 spd and mines auto. Youll eat civics alive unless their boosted. I wouldnt pay 1500 for that swap tho, that seems expensive if your gonna shell out that much might of well just do a 350.

 

I think he'll take $1,200... what do you think it's worth?

 

My LB9 runs low 8's in the 1/8th mile and makes 260 rwhp/ 404 rwtq. That is far from slow considering most third gens run 9's and slower. A few bolt ons and a 75 shot is all it took. Building a 355 to replace it though, should be in the 7's with a 100 shot for sure.

I would take the $1500 and just start on a build of a 350 and find a TPI swap. Its not like GM didn't produce a ton of TPI cars so the intake setups/wiring/sensors are not rare or expensive.

 

a lb9 swap could be had for far cheaper.

but like others have said, for that much do a l98 swap....you'll thank us later

but lb9s have seen 13's....but most fast 305's seeing 12's or higher are carb for a reason

 

You must have one hell of a stall converter to be running 400+TQ on 260HP. What mods are you running? Gears?

 

L98 would be fun... but my car is a daily driver... I go about 60 miles a day... I need to get good mileage! And an L98 would throw my t-tops lol.

 

meh if you drove the l98 like a normal person at freeway speeds it would get same or better than the lb9 due to more horsepower t over come drag caused by wind resistance.

Heck, my friend thats got a 383tpi car gets just as good of gas mpg as he did with mod'd lb9 lol

 

I daily drive my Modded L98. ported slp runners,ported base,ported SD intake,vortec heads,magnaflow catback. I still get around 17 to 18 on the highway and I dont drive easy.

 

I wouldn't waste the money on a Hypertech chip. I would do mods that would transfer over to a L98 later on down the road such as headers/exhaust/gears. If I remember correctly, my buddy's old 91 camaro rs 305 TBI car had 3.73's, 3" catback, etc and was only running 15.0's in the 1/4. (Stock for him was like 16.2) My car back when it was a stock 305 LB9 with a 3" catback and k&n air filters was running a 14.9 in the 1/4 and had 198rwhp/262rwtq.

Yeah, the LB9 would be a good paltform to start with, but eventually you'll want that 350. And its better to swap in a 350 once those other supporting mods are there.

 

Precision 2500rpm stall speed converter, full exhaust, 3.42 gears. A few other bolt on's, nothing major. Peanut cam. 75 shot out of a single nozzle (42 nitrous pill).

404 ft lbs is due to what some call "torque spike" with nitrous, but it didn't "spike" at all. It actually maintained high torque for a while.

These numbers were achieve at 10.5:1 Air/Fuel ratio. I have since leaned it out and the car feels much stronger.

Hasn't seen the dyno again yet. Now concentrating on a 355 setup that is currently a new thread that you guys are free to give me some input on.

 

What year LB9 is it, the 1990 and latter LB9 with the high flow exhaust manifolds were rated at 230 HP and run very well.

 

It doesn't feel slow out of the hole with a decent sized converter and a 3.42 gear, but then it falls on its face.

Spray it for a while and have a blast, but then you'll want more, and filling bottles just to have a good time on the street gets really old at $4 a pound.

I can't see buying an LB9/ 700r4 combo for $1500, you could probably find a wrecked 350 TPI car for that and swap everything out of it.

BTW, that 190hp is to the flywheel, not to the wheels, and that is in perfect running condition. If you were to put it on a dyno, look for around 150 rwhp, and that is also in perfect running condition. I never dynoed my car on motor but I would predict it would probably put down 190 rwhp with full bolt on's including RR's.

 

You dont need half of what hes selling. The lower half of the motor is the same as yours.

You can find TPI intakes w/harness for about 400'ish. Your choice of heads. Dont even have to pull the motor. Then possibly some headers or other goods.

The main thing for mpg is drive reasonable. Then tune tune tune on the prom chip.

 

i have a 91 firebird formula with an LB9, and despite my future plans, i run great in the quarter. i have a comp xt260 cam, 20 lb inj, port matched heads, base, stock runners, ported plenum and a lightly matched throttle body. has cold air intake, 185* thermostat, rebuilt 700r4 w/ stage 2 shift kit and TCI converter 3800 stall, stock 3.73 posi, flowmaster 2 3/4" catback with 40 series. stock bottom end, and i run consistent 12.40's, my best being a 12.37 @ 115.8 with 295 toyo proxies out back and 215's in front. i used to run bosch fusion plugs but recently upgraded to the E3's. definitely helped my around town driving experience and idle quality. i havent been to the track with them in yet, (the weather in the NW has officially hit the *******) but i hope for a slightly quicker et.

my point is that the LB9 can be fast, and yes ive put some money into my car (roughly 2200 in mods), you just need to know how to build them. i blew up my last third gen at the track, an 84 camaro with a 92 LB9 swap in it, but i got greedy and tossed too much juice at it (a 200 dpi shot with all stock except the runners, TB and rear end) and blew a couple pistons to hell. before the 200 it ran low 12s on a 100 shot.

neway, they can be fast, but if your looking for easy, low maintenance good performance, then build a nice 350 or find an L98. you can get one as cheap as your buddys, and youll be a hell of a lot happier.

ps- my firebird is getting a built 350 motor this next summer and a 6 speed. the drag strip is no longer fun for me, auto cross and hotrod cruise here i come.

 

That proves my point. Eventually he'll want that L98.

 

Spending 1500 bucks on a LB9 is just something you shouldnt do. If your dead set on having a 305 just swap a TPI set up onto your motor with some heads (even stock L98 would work, cheap too), 100 shot it at the track and get like 27 mpg on the way home. If you want a fresh motor all together, a L98, LT1, even some LS1's can be had for less than 1500.

 

Stock L98 heads will be a bad idea. They will drop the engine's compression too much due to their larger combustion chambers.

 

My bad, I always forget about the combustion chamber size difference.

 

Just get the L98 heads milled, to create a smaller combustion chamber, but be careful of raising the compression ration.

Thicker/thinner head gaskets can help "tune" the compression to where you want it.

Or get Vortec heads. WAY better flow, but then you hafta buy a new intake. Not a big deal, just a little more $ to spend, but stock Vortecs are CHEAP.

 

Not the best idea, I know we're talking about a basically stock 305 but I'd still rather see higher compression with an .040 quench height than lower compression with a garbage quench.

 

idk bout milling the heads that far to 58cc or less.......

local race shop told me they wouldnt take my L98 heads down that far because if the heads ever had an issue(piston hitting it or debris....they couldnt mill it anymore and head would be junk. So basically if you sprayed the lb9 and it blew up, you wouldnt have heads for the 350 replacing it