I have a 94 Z28 M6 and I bought a 94 LT1 out of a cadillac fleetwood to rebuild and swap in. Now I know the LT1 was used in the fleetwoods, caprices, impalas, camaros, etc.. but are there any reasons between them that should cause me any trouble swapping the engines? I haven't seen it yet and it was brought to my attention that it might be longer?? for some reason to supplement the tranny on the longer fleetwoods and caprices. does anyone know a little something about this, I dont.....

 

they are identical except for the heads and cam. I've done this swap for a couple of customers wanting to save a buck. You'll like the lowend grunt but you'll notice a difference on the top end.

Shawn

 

The one that is in my car now was out of an Impala SS and on thursday I bought another on out of a caprice for my next project. Those Lt1's have cast iron heads as opposed to the aluminum ones on the fbody and vettes, as well as a slight different cam grind to provide more tourque fot the added weight of the bigger cars.

 

might be a good idea to do a port job on those iron heads just to open them up a bit before you stuff it in the car.

 

It has a vented opti which is good. It has 2 knock sensors, removed the one on the driver side and plug it. And the exhaust manifolds are different, reuse the ones from the f-body.

 

Do you realize those lowely iron head flow more than the 95 on down aluminums and as well as the 96+ aluminums?
Sorry the iron is bad ignorance just hits a nerve with me.

 

LOL I always heard good things about these heads from my buddies; but everyone on here has told me to invest in an aftermarket set too or to get them ported, but I'm a newb, what do I know

 

If you want more than a stock motor sure port them or your old aluminums or if you want a wild motor look to aftermarket heads and porting, but stock for stock the irons outflow the majority of the aluminums so the iron hatred often seen on forums is just from a lack of information. If you want to go ported the aluminums already have screwin studs which is a plus for use with big cams, the irons are pressed in and they should be machined to screwin if you plan on anything with say more lift than the HOT cam with 1.6 rockers. The aluminums obviously weight less but sources I trust have weighted each and put the difference at more like 35# for the pair rather than the 50# often quoted. The aluminums have a smaller chamber for more compression but iron is more thermally efficent, each has plus sides and drawbacks and both are pretty good in stock form. As I said though I get tired of the anti-iron sentiment from many f-body kids.

 

ya i noticed on the specs for the cadillac that it had 260hp and 335 trq which is different from my camaro's 275/325. As far as for mods, My LT1 already has headers, full exhaust, cold air intake, and i plan on getting a twin 58mm throttle body, maye bigger fuel injectors....what else would be good, mild, money effecient mods that I should do while in there for say around 400hp (including what I mentioned above) I don't want to go too aggressive, this is my daily, but what are some ideas for some power gains, i was thinkin the lt4 hot cam kit with the 1.6 rockers and maybe getting the head work done like talked about above,but what else?

 

LT1s that came in the Fleetwoods were (in most cases) the smaller baby LT1 (265ci) rated at 200HP.

...could be wrong I suppose.

 

you are, the only b-body that came with the Baby LT1(L99 4.3L V8) was the caprice, it was the base engine, all other b-bodys came with the 5.7L LT1

but unless you pulled it from the Fleetwood, make sure its a 5.7L

 

And you would be wrong since the ONLY car the L99(265ci version of the LT1) was used in was the Caprice sedan with rumors of a Caprice wagon or two. The LT1 was standard in the Fleetwood the Roadmasters sedan and wagon and standard in the Caprice wagon. You guys can't even claim the LT1 was standard in the f-body. When comparing rating also compare what it was installed in the b-body has a quiet intake and exhaust yes it has duals but they are 1.75 inside, the square box after the MAF is a proven 9hp restriction at the wheels and it was tuned for 87 octane. Since you guys got single exhaust let's call that a wash but I still think your intake was less restrictive and I may be wrong but isn't the f-body tuned for more like 91 octane instead of 87 right there you make up some of the HP difference and torque is higher and starting at a lower rpm range. The way it loses power at high rpms is often just the valvesprings they are known to float as low as 4800rpms but the fast bolton cars routinely rev past 5600 with better springs and seeing as several are in the 12s that dinky cam must work OK. One freak car with a VERY special converter has even gone 12.3 yes he has lightened but still I bet a lightened b-body is still heavier than an f-body. My point is look at the package and don't just look at the numbers there are variables that have a signifigant impact on those numbers.
To get a solid 400hp out of an LT1 your best bet will be heads and cam, how wild on the cam will depend on how much you sink into the heads, you can do it with just a cam but you may not want to go big enough to get there.

 

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Look into the LT1-LE2 package.

 

A buddy of mine used the LT1 out of a caddy to build his 355. The intake, heads, cam are all different. What you should do is pull the heads off your old motor and either have them ported or at the very least pull the damn cast iron heads off in place of the aluminum. And youll really wanna get a cam if its all appart already because IMO its really a waste to do the cam swap later when everything is so easy to get to now... it would be real mistake not to.

Unless you add a larger cam and heads then stick with your stock injectors. Larger injectors dont mean more power unless the motor requires more fuel than the stockers can supply and that will take a heads/cam motor to do.

 

[QUOTE=...but iron is more thermally efficent..[/QUOTE]

What do you mean? Aluminum conducts heat approximately 4 times better than iron.