Hey all,

I can't seem to find exact numbers on the weight of these two engines. I've decided the long term goal w/my base 'bird is to do the LT-1/T56 swap. I'm wondering how much more an LT-1 engine would weight than a 305 TBI. Would the added weight of a T-56 vs a T5 prevent it from making too much of a change in the front/rear weight distribution of the car?

Lastly, what kind of curb weight can I expect from the car after this swap? I have a base '91 bird, w/no ground effects, no power door locks, or power windows. I think right now it weighs between 3250 and 3300 or so, but I'm not sure. Thanks for all help!

 

F-Body and Corvette LT1 should weigh 50-70lbs lighter.
The T56 will offset the weight difference, making both the LT1/T56 about the same weight as the L03/T5 setup.

 

But the extra weight is farther back and lower, so it's still an advantage.

 

Mmm..virtually no curb weight increase, and better front/rear weight distribution..I love it already!

I had a couple of somewhat on-topic questions, but mainly just regarding to modding my car in general. Since I gotta pass smog where I live (Not CA, thankfully), I wouldn't think it would, but I was wondering if anything like gear ratio changes, or eliminating the skip shift in the T-56 would hurt my chances of passing emissions at all? I was also wondering if the LT-1 has some any kind of traction control system on it (in case I need to have it bypassed).

And I'm really not going for anything too crazy, probably just a stock motor w/exhaust and headers, maybe some other bolt-ons, but how much power is it possible to make on an LT1 and pass smog? Thanks in advance!

 

If your pockets are deep enough, getting an LT1 to 800 legal horses can be done, and has been. More gearing sometimes actually gives cleaner test results, depending on the type of testing, if you don't get too crazy with the gearing. If you're using a '94.5-'97 T56, then 3.73:1 with the stock cam, or 4.10:1 with most aftermarket cams. If you're thinking cam swap, think something like a 218/224-112, 495/503 from COMP.

 

800?! what's the secret to that? lol. The 305 I have didn't fare so well when I took it in for testing, but may pass now since it's had some work done to it. When I did take in it though, they checked for engine light codes, and used the tailpipe sniffer to measure hydrocarbon and CO output. Not really sure if they go by different levels for different years of cars, but I would imagine even a lightly modded LT-1 would still burn cleaner than a Gen I small block, right?

Gearing-wise, I'm debating between 3.42 or 3.73 w/the T-56. I'm looking for a good blend of power and economy, since it's mainly going to be a street/summer car. I'm only aiming at somewhere between 300 and 350 ponies at the crank for now, which I imagine shouldn't be too difficult w/an LT-1.

 

the secret is boost.
Forget the 3.42:1s. Even with 3.73:1, you're still turning just 1600 rpm at 65 mph.

 

So in other words, 6th gear is completely useless with anything numerically lower than 3.73's and I may as well take advantage of some extra get up and go?

 

with a stock LT1, you could use a 3.42:1, it'll do 1430 at 65, but you'll downshift for every little breeze or hill, and there goes the mpg. Unless you already have the 3.42:1 gears, forget them.