400sbc or LT1??

[BOXCHEV]

I have a 87 chevy caprice Fuel injected 4.3l V6 262cid(weeeaaaaakk) lol

This will be an street car btw..

Right now I'm trying to think between a 400sbc(2 bolt or 4 bolt) or an LT1? any input? Looking to get high 400 to low 500 Hp and torque out of either and im looking put a 700r4 tranny behind one of them with 10bolt 8.5 rear.

Now Im no expert at building engines so excuse any ignorance please.

I have been looking into buying just a new block and building it from there everything thing new. But buying either of these engines new are like $2,500++

I have came across a few on craigslist for pretty cheap. Even seen two LT1's for $750 I passed on them and a 400sbc for $400.

Does miles on the engine play a big factor? Like should I even consider buying something that has 150k or so miles on it already or does it matter. Roughly how much would it cost to completely have the engine machined?

I plan on keeping AC and not sure if I want to stay fuel injected or not.

Also any tips on buying any of these engines if I get one off craigslist? I dont want to go get one and take it to an machine shop to find out its no good.

[mrcadillac]

I would really consider an LT1 for many reasons.

Fuel Injection is the way to go. For quite a few reasons. Better fuel economy, better Air/Fuel ratios(which means more power), you can do tuning with a laptop, you can push things closer to the edge. Plus, the LT1 ignition system is much more advanced than an HEI. You can run more timing, and it will be safe to do so because the spark is exactly where you want it. The spark doesn't roam back and forth a few degree's like HEI's do. the tuning bit is nice. It makes it easier to change shift points, shift firmness, when using a 4l60e over a 700r4. and since the 4l60e has been out there for a while, they are pretty cheap.

A Carb is like a slow gas leak at best. They work, but there's a reason every car company went FI. Even motor cycles, and Jet Ski's are going FI. Also, FI motors tend to run longer, since the motor doesn't run as rich at start up. Carb motors would dump in so much fuel, that is washed all the oil off the cylinder walls, which cause more wear, and put more gas in the oil. neither of which is very good.


A 400 SBC is quite a bit older, pretty much a garentee it will need machine work. and IIRC, they were notorius for blowing head gaskets, and over heating. which can lead to a bunch of problems, like core shifting, warping, cracks, etc. Not saying it will happen, or that it's a bad block in general, just that it's something to keep in mind.

I have/had 8 LT1 cars. Milage ranging from 80k-230k... They all ran great, even with over 200k miles. 100k on an LT1 is nothing. What kills them is high reving them, and not having enough oil pressure. Normally what goes first is the rod bearings. So it would make sence to get an LT1 from a Grandma car, instead of a sports car. The short blocks are all the same. A corvette got the 4 bolt mains... but the 2 bolt mains have shown to support LT1 350's with heads and cam packages, making an honest 500-550hp. I would consider the 2 bolt block a plus over a stock 4 bolt block. since you can go splayed 4 bolt mains on blocks that are originally 2 bolt blocks. I have seen inside LT1's with 200k on them, and you can still see the cross hatch from the factory, on the cylinder walls.

I would use a 4L60E, over a 700r4 aka 4L60. they are pretty much the same trans, but the E uses solinoids, and needs a command from the PCM. If the PCM is already controlling the engine, why not let it control the trans as well. The trans wiring is on the same harness as the engine's sensors.

An LT1 is packing 260 Net hp, 335 Net Torque, in even it's mildest form. In it's stock form, it's pretty potent in a 3800lbs car. I have sold a few perfectly running Bare long blocks for $300-$350. You could pick up an LT1 caprice, roadmaster, or Fleetwood, that has been hit, or is rusting out, or in bad shape, for pretty cheap, and then pull the motor, trans, and rear end all from the same car. You could even use the driveshaft from a Caprice, or Roadmaster, as the wheel base is the same as an 87 caprice. I've seen a few LT1's in 80's Caprices, and they are pretty bad ass.

I think in the long run, an LT1 would be cheaper to build, since it has quite a bit of power stock, very good heads(not quite LS good, but very good for a SBC). Just by changing the cam, you can get an honest 400hp out of them. you would likely have close to, but not quite 400lbs of torque. You could build a 383, or a 396(actually 395), and then you would for sure have over 400lbs of torque with the right build.

Another thing to keep in mind if your look at crate motors from say Golen, is that they rate the motors by Gross Ratings. Which actually is an over rating. If you compare it to the way they rate motors in production cars, you need to reduce the rating by 15-20%. like a stock LT1 would be rated at roughly 350 gross HP!! Also, if you find a build in a magzine and it has 400hp, you have to remember it's a gross rating, not a Net rating.

[mrcadillac]

Oh yea. Since the frame of an LT1 caprice is nearly identical to an earlier frame, almost everything drops right in place, and bolts up. A few differences is that a 94-96 trans crossmember won't bolt to an earlier frame, and you will need to notch to frame to clear the A/C compressor. Other than that, you could pull an LT1 from a caprice, and drop the entire drivetrain in, only having to fab up a few things, and worry about wiring. if you bought an entire donor car, you could have the wiring harness for the engine, trans, and inside the car parts of the wiring harness.

I think you will need a mechanical bit for the trans, so the speed-o still works.

[BOXCHEV]

Wow thanks for that reply, I was waiting and didnt think I would get any response. Its funny though I read things on other sites and some say it would cost more to build the LT1, or some they would cost about the same to build. The over heating on the 400 was scaring me away.

I just need something around the stock area first, so I can pass this Cali smog. Then after that I will go all out.

I was just looking at an LT1 for $500 and an already built 400 for $500.. I always really wanted an Lt1 anyways.

Looking to get me a two door and hopefully I can come across a nice cheap LS1 :devil:


By the way the one Im looking at is coming out of an Z28 were those 4 bolt?

[mrcadillac]

shouldn't be, but they have been found.

[IMPALADAKID]

I paid $300 for a complete 95 LT1 out of a salvage yard with around 100k on it.
They are getting to be real cheap.
Besides, carbed motors are dinosaurs. The 400 in your 87 will not pass a visual or sniffer emissions inspection.
Most states will allow you to transplant another year engine as long as it it the same year or newer.
Besides I do not think the 400 could get 18-25 mpgs like the LT1 can.
Also, you will not see 400-500 hp with just $2500. That kind of power would need a transmission to support it. That is at least 2k by itself.
A stock LT1 with intake and exhaust will give you 300hp in stock form. That will feel like 500 hp compared to your 160-180 you have now.

[AdioSS]

see, I'd go with a 400 inch engine over a 350. I've been tempted many times to convert to a Gen1 SBC in my IMpala...

[BOXCHEV]

Been meaning to do some research but I have been without a computer for a while I finally got around to fix it..*old hard drive had its day

So anyways Im going to try an rent a truck tomorrow and go pick up this LT1
with 155k comes with


Y-pipe
Intake manifold
Long block (oil pan, block, rotating assembly, aluminum heads)
Exhaust manifolds
Optispark distributor


I think I want to just do a complete tear down on it, go get it machine and clean it up a bit. Get it painted then start working on the bottom end

Are there any nice complete kits out there anyone could recommend? I want forged pistons and stock everything else for the bottom I think that may do fine.

I want to do

383
LT4 top end kit maybe
procharger

Top end I want to keep the budget around 2,500 May be willing to stretch to 3k

Im looking to get around 450ish Hp trq some where around there

I was thinking about an LT4 top end kit, but then I read its not really worth it any opinions on it. Also wanted to do a procharger.

Budget is around 4k...Im talking just all parts.

Going to look for a 4l60e trans going to need a new drive shaft as well. And Im going to go with an 8.5 10bolt rear posi not sure on gears yet.




This will be a weeked type of car, might want to hit the freeway now and then and of course the track just to have a lil fun :D




Open to all suggestions

fuel pump
mains
crank
rods
set of pistons
Port the heads?
Hot Cam?
Injectors



I might just start a new thread Might not get any responses here

[mrcadillac]

F*ck the LT4 top end kit. You can get better stuff, for the price. have the Heads you have, ported by Advanced Induction.com . Get a cam from them, and then run circles around stock LT4 heads. Screw the Hot Cam, there is much better stuff out there now. Like a custom speced cam, which gets the valve events where the engine wants them, and doesn't have the Emissions compromise LSA of 112*, or worse, more(other cams).

Fuel pump: Walbro 255lph, and get a Racetronix pump kit with it.
Injectors: 30 lb/hr SVO's might cut it, otherwise one step higher, I think 36?

You would be wise, to leave the bottom end alone, and put that money twards a built trans. Get a trans from a place that has proven they can make them last, like say ProBuilt Automatics. 700r4L60e.com .

Put one of AI's heads and cam on a stock short block, and you will kill a Stock 4L60e in no time. prolly about an oil change. My 96 caprice has a smallish cam, with full bolt-ons, and has killed a few stock transmissions before I got the car. You gonna want to spend a decent about also, on a nice torque converter. a very nice performing unit, with cost about $500-$900. A properly built trans is going to run about $2,000-$3,000, depending what you go with. You should know, that there are alot of builders who think they know how to build a 4L60e, but they just don't last... even at STOCK power levels.

You might want to rethink the 383, and put the money twards the heads, trans, and a rear end rebuild(which will cost around $1,000 to do it right), and your supporting bolt ons, like headers, exhaust, Tune, suspension upgrades(caue it's gonna need them to plant the power effectively).

[MALIBU 9C1]

I'M NEW TO THIS FORUM AND LOVE IT SO FAR.

heres my plan. feel free to give me advice.

81 malibu 2dr. i have a good running complete 95 9c1 donor car that i plan to transplant complete injection, heads, trans, rear, and maybe even abs.

i have a stroked 400+ small block 10:1 (short block) already built that i'm planning on using instead of the 5.7 in the car now. the stroker is a race motor and needs a cam so i'm looking at picking one that will work with this application. i'm hoping i can use this short block because its already shown its 600+ hp capable. this is going to be a clean built modern street rod to be driven long distances frequently and beaten occasionally.

does anyone have an advice about the engine combination? i want to do this right and have everything work.

thanks in advance!!!!!!

brad in nj

[mrcadillac]

Unless the 400 is an LT1, the heads won't bolt up.

The LT1 is a Gen-II engine. the only other engines from that family are the 4.3 L99, and the LT4. Heads don't interchange to the Gen-I engines. Which were the Standard small blocks used from 1955-1999ish.

The race motor is gonna make 600hp, because of the heads and cam you use... you could use better heads than STOCK lt1 iron heads. A set of ported stock aluminums flow very well, but a GEN-I has many many more head choices. BUT, GEN-II heads don't work.

I feel that part of the LT1 swap, is the cool factor of a new motor in an older car. There are some stock bottom end LT1's floating around with about 500 hp at the flywheel(Net), roughly 400hp to the wheels. and they are doing this with ported stock aluminum heads, and not that aggressive of a cam.

Heads are where the power is at, don't cheap out on them.

[MALIBU 9C1]

i'm 99% sure its a gen1, it ran 461x heads and is an older block. :mad: i initially planned on running a tpi set-up on this as i also have a complete donor 86 iroc 5.0.

are there aftermarket heads or a cross over intake that can be used on this block with the lt1 set-up? otherwise i run the tpi or do a complete rebuild on this engine.

thanks again!

[KW Baraka]

.......are there aftermarket heads or a cross over intake that can be used on this block with the lt1 set-up?.......

What LT1 "set-up" are you talking about?

A Gen-I block will not accept LT1 Heads.

A Gen-1 block and heads WILL accept the LT1 intake......if the intake is modified.

There are quality Gen-1 heads out there......I'm sure of that.......but I'll be damned if I know enough to help you in that area :( .

KW

[Lt1]

If I may be so bold, I'd like to point out that some very good advise and a wealth of shared knowledge has been bestowed upon you. This is where you help yourself get off the fence about which engine to go with. There are great sources of info like how to build & modify chevrolet small block cylinder heads, cam selection, ect., if you want to use the old school approach. But in my humble opinion... how could you pass on a more efficient LT1 that has many upgrade options... both green and offroad?

Maybe I misread you intentions but, didn't you say you wanted to be able to do cross-country or daily driving?

What is your primary use of this vehicle going to be?

Lt1

[4doorvett]

Go with the LT1, nuff said.

[AdioSS]

There is no replacement for displacement. Go with the 400 and put a good set of aftermarket heads on it and a good single plane intake.

For what it is worth, Gen1 heads will fit a Gen2 block (with a little work.) And Gen 2 heads will fit a Gen 1 block (again, with a little work.)

[five7kid]

There is a replacement for displacement - efficiency. That's where the LT1 engines (and LSx, for that matter) shine.

If you really need the displacement, stroke the LT1.

[4doorvett]

There is a replacement for displacement - efficiency. That's where the LT1 engines (and LSx, for that matter) shine.

If you really need the displacement, stroke the LT1.

+10

[91chevywt]

While the 400 will probably make better peak torque and better peak power (maybe) it will definetly be a pig when it comes to fuel mileage. Also, with the fuel injection with the LT1 your power and torque curve will be much wider...with a carb no matter how you tune you are compromising somewhere. My vote is for LT1. If you had some money, a 383 LT1 will haul some @ss

[ShowNoMercy]

Take the 400 crank, grind it to fit in a 383 SBC and make power with a carb.

[five7kid]

Still makes more sense to do that to an LT1 than it does a Gen I.

[ShowNoMercy]

You can convert a two piece seal to a one? Pardon my lack of knowledge....

[4doorvett]

While the 400 will probably make better peak torque and better peak power (maybe) it will definetly be a pig when it comes to fuel mileage. Also, with the fuel injection with the LT1 your power and torque curve will be much wider...with a carb no matter how you tune you are compromising somewhere. My vote is for LT1. If you had some money, a 383 LT1 will haul some @ss

You can stroke the LT1 out to a 396 or better for a few xtra $$$! So there's your 400 sbc mpfi FTW! Karl Ellwein of Ellwein Engines, Need I say any more?

[KW Baraka]

You can convert a two piece seal to a one? Pardon my lack of knowledge....

Yes......and you don't even need to monkey with the crank to do it.

GM Performance Parts sells an adaptor to use 2-piece cranks in a newer one-piece block ;) !

Still.......it does make more sense to go with the LT1 set-up........

IMHO, of course.

KW

[ShowNoMercy]

Woah, so I could source a crank from an old 400 and get it machined to fit in my LT1?

[mrcadillac]

Woah, so I could source a crank from an old 400 and get it machined to fit in my LT1?

why would you wanna do that? the same stroke(3.75"?) cranks can be had new, already for an LT1, for not alot of coin. Infact, you can get a crank with even more stroke to go for a 396, with the 4.00(then bored out .030) bore size. What the 400 has going for it, is the larger (4.125"?) bore.

[KW Baraka]

.......What the 400 has going for it, is the larger (4.125"?) bore.

Typically, stroke is better than bore.

KW

[mrcadillac]

Unless you wanna really rev it.

[KW Baraka]

Larger bore = larger pistons = more weight on the end of the rotating assembly = less rev happy.

IMHO, of course.

FWIW, the WOT shift point for my 396 when I had the CC-306 cam was 6700 RPMs.......

KW

[91chevywt]

Larger pistons are slightly heavier, but not enough to make a difference. Longer stroke=longer time the piston scrapes the cylinder wall. Longer stroke engines=better low end power and lower rpms generally. A larger bore with a shorter stroke makes it easier for rpms to be generated because the pistons aren't reciprocating as far. If you had two engines that displaced exactly the same amount, and one had a longer stroke while the other had a bigger bore, the big bore would run more rpms while the long stroke would make better low end power.

[five7kid]

It's almost impossible to make all other things equal.

But...

Taking a factory 400 crank and fitting it into an LT1 block would cost you as much in the end as getting a one-piece 3.75" crank new, and the new crank would be a better piece. And, as stated, you could also go longer.

383 LT1's are all over the place. But, not sure I've seen many/any in a B-body.

[KW Baraka]

........383 LT1's are all over the place. But, not sure I've seen many/any in a B-body.
Only because you don't know where to look :lol: !

KW

[mrcadillac]

Or where to look for a 396? :D

[KW Baraka]

Or where to look for a 396? :D

Agreed :lol: !!!!

[five7kid]

Only because you don't know where to look :lol: !

Probably true.

[BOXCHEV]

Forgot all about this thread, been doing a bit of reading on the impala ss forums archives mostly about mods for the lt1.

Okay first off I had an 94 lt1 from an 9c1 caprice, turns out the block was no good after taking it to machine shop plus I would have had to bore it out too much, more then I want to anyways. I already parted it all out so its gone.

Well Ive done a search on google an few other forums and havent gotten any good results yet but Im checking out this 94 LT1 from an z28 camaro with about 90,xxx miles on it.. complete motor. And Im wondering what kind of things will I run into when trying to drop it into my caprice? Will I have to use an fbody wiring harness/ an computer or can I use a body harness/ an computer? Thinking of just using an wiring harness from Painless performance anyways.. I know I will have to notch the frame to clear the ac compressor and I plan on switching out the non vented opti for a vented one once I find 95+ timing cover an other misc parts needed(already looked up how to do it). For the most part do most parts from an bbody lt1 block swtich over and bolt right up to an fbody block??

[91chevywt]

Forgot all about this thread, been doing a bit of reading on the impala ss forums archives mostly about mods for the lt1.

Okay first off I had an 94 lt1 from an 9c1 caprice, turns out the block was no good after taking it to machine shop plus I would have had to bore it out too much, more then I want to anyways. I already parted it all out so its gone.

Well Ive done a search on google an few other forums and havent gotten any good results yet but Im checking out this 94 LT1 from an z28 camaro with about 90,xxx miles on it.. complete motor. And Im wondering what kind of things will I run into when trying to drop it into my caprice? Will I have to use an fbody wiring harness/ an computer or can I use a body harness/ an computer? Thinking of just using an wiring harness from Painless performance anyways.. I know I will have to notch the frame to clear the ac compressor and I plan on switching out the non vented opti for a vented one once I find 95+ timing cover an other misc parts needed(already looked up how to do it). For the most part do most parts from an bbody lt1 block swtich over and bolt right up to an fbody block??

There shouldn't be much issue with doing it with an f-body block. I actually have a block from a 94 caprice in my camaro, and I'm running an f-body harness and ecm (1993). I can't answer all your questions, but I hope I can help you with some. You won't have to use an f-body harness. The only real difference between harnesses is if you are running a speed density system or mass air flow system. For some ecms, there is a crankshaft position sensor required, I know for my ECM I didn't need it. There is a slight difference with the water pump since I believe most of the b-body motors didn't have an oil cooler. The water pump may or may not have an extra port for an oil cooler, and also there will be an oil cooler collar on a 94 f body motor, but you can get rid of that if you want. Other than that everything should bolt up.

[KW Baraka]

......Im checking out this 94 LT1 from an z28 camaro with about 90,xxx miles on it.. complete motor. And Im wondering what kind of things will I run into when trying to drop it into my caprice? Will I have to use an fbody wiring harness/ an computer or can I use a body harness/ an computer? Thinking of just using an wiring harness from Painless performance anyways........

F-body block and B-body block are exactly the same.......exactly the same.

If you're gonna keep it fuel injected, then you'll need to have the PCM custom tuned, probably with a derivative of the B-body progaming......call www.pcm4less.com (http://www.pcm4less.com) ;) .

Also.....the F-body wire harness will be worthless in your car......get the one from Painless.

KW

[BOXCHEV]

Thanks 91chevywt an KW Baraka helpful info,

Yes I will be keeping it fuel injected and a pcm tuned after everything of course :D

Im not sure what compression to go with, hoping to come across are nice used ati charger sometime next year. I will be using the Stock crank, .30 over and Forged pistons and Rods (suggestions?? Part #'s??)

[ShowNoMercy]

For rods and pistons?

I am looking at Scat H rods and the Mahle power pak for pistons.