i have an 81 camaro Z28 i've had the car for about a 1 1/2 yrs. the car had a 400sb in it when i bought it and the guy said it had just been rebuilt and this and that blah blah blah....anyways its running like crap and leaking oil everywhere. i'm looking to pull this motor out and set it aside for use with a later project. i'm planning on getting some kind of late model engine from a junk yard to put in. what should i look for? can i get LS1 or LT1 and run it with a carb or what? also what are some horsepower ratings on some late model motors? thanks for your help

 

Instead of buying a new motor, i would use that money to rebuild the 400cid. Leaking oil is gaskets. You can buy all new gaskets, but it wont hurt to have it rebuilt again. Just because a motor is running like crap is no reason to buy a new motor. and i would much have an old 400cid then a new ls1 or lt1. find the leaks, and fix them. a major oil leak is jsut a gasket somewhere. when it does run, what color is the exhaust smoke? if it is blue then it has an oil problem, but if it is clear or slighty white, then the motor is probably worth keeping. if it is running crappy, ask around, and find information on it, this is a forum, so ask someone. I would jsut personally keep the 400 and not buy anything else, especially a motor full of electronics like an ls1.

 

Timmy, he can have a 425 rwhp engine that is capible of everyday driving and get good milage with an LS1. One option is to get the engine/trans/wireharness from a wrecked car, it won't be cheap but everything you need will be there (for the most part). Painless Wiring also makes a harness kit. Yes you can get a carb set up for an LS1 and that would eliminate the need for any computor managment system. Edelbrock makes the intake manifold and MSD has an ignition system for this type of conversion. If it were me I would stay with fuel injection, the tunibilty and drivibilty are much better than carbed. And yes I have owned and tuned many many carbed motors.

 

They make kits to put an LS1 in your car. They are a bit involved but straightforward, take it a step at a time and you get there. You have the choice for running a carb (they make carb kits for the LS1 now) or installing an LS! crate engine with computer and F.I. the carb unit produces nearly as much power but driveability is not as good and torque curve not as flat. Up to you.

That said, it would be costly: for the engine, for the conversion kit, for a host of tiny nit-picky problems. I'd guess the LS! would cost you a minimum of $4k, the kit, $1k, and the other stuff another $1k. $6K and you have a super car, but . . . You could either rebuilt the 400 for much less, or buy a crate engine that would fit in. If it were me, the decision would rest by what type of bottom end the 400 had. If it was a solid 4-bolt main and in good condition with a good crank, etc., I'd rebuilt it right. If that was going to take a while and I had to drive it daily, I'd drop a cheap surplus engine in for a while even a 305 just to get it moving (and sell it later to get my money back) and take the time to do it right. A $1000 and the time to do it right would put it in prime shape. $2000 would give you a jewel - it would never equal an LS1, but it would be really good, and then you haven't spent the other $4k either.

 

well went out to the car this evening and pulled a plug and it was covered in oil!! so i pulled all of them and about 3 or 4 were covered in oil some worse than others and the rest were kinda burnt up. the thing is that i changed them before my last trip to the track this year so about november and i havent driven it but maybe 4 times with the new plugs! so what is up with that? the guy i bought it off of said the motor was rebuilt 2k miles before i got it so that would be maybe 5k ago now but i highly doubt thats the truth it sounds like BS from the way it runs and leaks. i'll probably end up keeping the 400 and rebuilding it if you guys think thats the best thing because i've heard the 400sb is a pretty solid motor. the thing is though im caught up in building a footbrake car right now and dont really have the time to fool with building another motor so the reason i was looking for another motor was to save myself alot of work. by the way the car is not a daily driver.

 

Several points:
First , there are engine rebuilds and then there are engine rebuilds. I am always suspiccious of any "rebuild" done right before the guy sells the car: tendancy is to cut corners because you won't have to live with the consequences.

Can you diagnose the oil on those plugs? Important point is where is it coming from?
It might just be drifting down through the oil guides onto the valves and into the engine when it sits: does it blow a puff of blue smoke when you start it but then stop smoking? This is fairly easy to fix- the heads have to come off (and if not on a tight budget I'd use the opportunity to replace them with ported heads, and put in a cam), but the cost just to fix this ins't that much.

Or, it could be serious blow-by the oil control rings in which case the engine has to come apart and you must check bore, pistons, and install new rings. I'm leaning slightly in this direction based on what you say, but its not that definate. And in the worse situation you would find that the engine cannot be bored or honed any more and you need a new block. (Not trying to scare you, it may be that this "rebuild" consisted of just honing the cylinders in the guy's garage and installing the original (worn, now a little small) pistons with new rings, you don't know). This trick of using the old pistons saves money, and it often works, but it would not surprise me on an old engine if a couple of cylinders went bad, soon. You can sometimes tell by the sound on start up: the pistons make a slight slapping noise before they warm up - you might find a friend (an older guy like me) who has heard this before and ask them if they hear it. If so it is a good clue to what the problem is.

 

yea there is a puff a blue smoke at startup but then it goes away. i dont really know what the story is of the supposed 'rebuild' because the guy didnt give too much info about it. also i found out that 2 of the bolts on the tranny pan are stripped and leak from time to time i installed a new gasket a while back and thats when i discovered it the new gasket slowed it down a little bit but other than that the tranny runs good no slips or anything. the body is actually in great shape thought

 

Here's what I'd do. First, a compression test. This ought to give you a hint -- hard to imagine the compression would be spot on (as it ought to be on an engine rebuilt correctly only a few thousand miles ago) if the rings are bad. Test all eight and the 3 or 4 that were badly covered with oil - if they have less compression, then, yeah, the engine has to be rebuilt.

But given the way it puffs at start up, I'd guess its the valve guides and that your compression will be okay. In that case you can live with this for a while if you need to. You'll be buuying new plugs alot and/or learning to clean and gap them frequently, but there is nothing dire about worn valve guides: the car puffs smoke on start up, the plugs get oil on them, and it will all gradually, emphasis on gradually, get worse, big deal. Long term you want to get this fixed (i.e., you won't get another 50K out of these heads without it becoming so bad you approach the car with dread, it getting pretty bad).

So, the compression test is the important diagnostic.

 

What I was saying before was i would much rather keep 400. Even completely rebuilding the motor would most likely be cheaper then buying a new or even a junked ls1 because new will be too expensive, and a junked one will most likely need some money put into it to get it back in reliable shape. Not to mention its easier to buy parts for the old 400 and cheaper. Lee Willis pretty much got it on the dot.

 

No doubt about the 400 being cheaper, thats a givin. LS based engine are great but they are not cheap.