Is this possible? Does the LT1 block/head combo require the plastic fuel injection intake thing, or could I buy an aftermarket intake and slap a quadrajet on there? If so, would it be worth the trouble? Thanks!

 

You can carb an LT1. There's nothing saying you can't. The only real difference is the dry intake. That's about it. I don't see why though. It's not like TPI. It's a good design to start with.

 

Well, I just saw a LTI sans intake and harness for cheap, so I was wondering if it would be worth slapping a carb on it. Then it'd basically be a carbed 350 with aluminum heads, right? Would you use a pre or post 86 intake? Thanks for the speedy reply, and anyone else is welcome to chime in.

 

Yea, all the LTx engines are are basically reverse flow with better factory heads. There's no magic behind it.

If it were me, I would just grab a carb intake that is designed for the LT1 series of engines to ensure proper alignment and what not. Then again, I do not know how well the ports line up between the two.

Another thing to consider though: The LTx engines use the opti-spark system, so an LTx carb intake might not have the distributor hole in the back. You could pull the same stunt as seen on lt1intake.com and drill a hole and fab something up. Might want to look into how well the ports like up, though.

 

Hrm...Thanks for the info. I was searching around and found another post where some said that GM makes an intake specifically for thise purpose, that uses a normal HEI distributor. I'm intrigued. A carb'd LT1 would be pretty cool, and would sure beat a stock LG4. Now I'd just have to get it past the smog guys...

 

GM makes a 4bbl manifold just for the LT1/LT4 engines. You can take a look at GMPP website, and prolly Summit/Jegs too.

 

Yeah, I think I found that manifold, but it doesn't explain it very well. I think it's p/n 4502592. It appears to have a hole for the distributor. I know the Gen II blocks have reverse cooling, and I don't see where the top radiator hose would go. Would this be smog legal in CA?
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EDIT: does the coolant flow directly into the heads on an LT1 or something? Is that why there's no hole for a hose to the radiator on this manifold?

 

Yea, the LTx engines are reverse cooling, meaning the coolant goes to the heads, then the block. The water neck is actually located on the water pump itself, rather than the intake.

 

Your not getting past the smog ***** in cali with a carb on anything but an original thirdgen engine with a carb, or a package that has an E.O. number like the GM kit, if you want power and to get past those idiots, install the LT1 with the efi..

 

Stekman: thanks for your replies, and clearing up the coolant thing. That makes sense now.
I figured it would be pretty tough to fool the smog guys wtih that... But maybe it's possible somehow. Maybe there's a way to make it legal, since I'm swapping in a newer (cleaner) engine or something. Anyone here familiar with the CA smog laws?

EDIT: Z28racer, did you mean that if I bought the manifold/kit from GM, it would be smog legal?

 

The way smog laws are setup, as far as I know, its pretty much an all or nothing setup. You are allowed to go forward in technology, but you are not allowed to backstep. I don't think mix-and-matching parts like that would go over to well. However, they would be just fine if you swapped in an entire LT1 engine.

I think what Z28 is saying, is the numbers have to match, so to speak. Everything has to be original. For example, your current setup (Q-jet) requires an cast-in-head EGR crossover, which Gen. II LT1 heads do not have. You would have to run an external EGR. Don't think the smog boys would like that. The other thing would be a crate or something that GM has labeled as 50 state emissions legal. Like I said, as far as a newer engine goes, its pretty much an all or nothing type of thing.

Now I need sleep.

 

Im the only one on this site thats running a carbed LT1..well actually an LT4..the LTx motors have a dummy drive stub that bolts in the lifter valley..so it drives the oil pump off the cam as in a SBC, but the distributor isnt there...the carbed intake has the hole there so its pretty strait forward....as far as the hose routing is concerned, im running the stock TPI radiator and i ran the top hose to the thermostat housing and the lower hose to the lower outlet...never gets above 195...infact on the hiway it runs to cool..

 

i got mine from scoggin dickey for 249...i think the LT1 was a little cheaper

 

quick question for you LT1 guys..

doesn anyone know, why some older cars, early 70's and such, had engines called LT1?

 

I think it was LT-1. GM should've labeled them a little better :P

 

That was just the RPO code for the 350/370hp engine in the Z28 and the Corvette... just like L88, L79, L82, L69 are also all just RPO codes for diferent engines GM built over the years.

GM reused the name again in the early '90s to try to get back some of the 'magic' that the LT1 name had back in the '70s. Nothing more.

 

Ok, so if I get the LT1, and slap the carb manifold on there, I won't need to change the fuel pump, will I?

 

If you want this car to be street legal, you cant use a carb at all.

 

Yeah, I'm starting to realize that. But by the time I'll actually finish this motor and put it into my car, I'll find some way around this. Somehow. But regardless of that, the stock fuel pump will be ok, right?

 

Yes.

 

Stock fuel pump.... for your car? Or for the LT1?

 

The stock pump for an '87 LG4.

 

If it will bolt up to an LT1 block, then yea, it would work.

Only one problem though... I don't think LT1 cams have a fuel pump lobe on them do they?

I'd just go with an electric pump that will work with a carb. Just my though.

 

You should have 2 pumps. The intake helper and the block mounted mechanical.

I'm with Adam (and he's correct, LT1 cams do not have the fuel pump eccentric, not certain about the block castings and whether or not they are machined for them), I'd use a generic inline electric mounted near the tank somewhere.

Call up your local testing station or wherever and see just how legal it is first.

 

Forgot the LG4 used a mechanical pump, I was thinking low pressure electric. LT1's do not have an eccentric on the cam, nor do they have the mount on the block. Even if they did, the A/C compressor would be right in the way.

 

Ok, so that means I'd need a new inline electric pump as well as a new in-tank pump?

 

I would yank the in-tank pump and get an LG4 strainer or fab your own. You wouldn't need that factory pump. Just get a good elec. pump and mount it back there somewhere.

Kind of pointless to have 2 pumps within 2 feet of eachother.

 

Hehe, ok that makes sense. Thanks

 

Hey guys, I've got some pretty suprising info on my swap here. I spent a fair amount of time on the phone with a guy from CA's smog referee program, and he said that as long as it have the same emissions equipment as my 87, I can use the longblock from the '95. If I used the FI (which I don't have), I'd have to put in the tranny from a 95 as well. So basically, if I can find a manifold with an EGR provision, I'm totally smog legal, and it doesn't even count as an engine swap, just an engine replacement. I guess the logic here is that you could get a 350 in a 87, and the LT1 is still a SBC, and there's no external difference between the 350 and 305. So anyways, if no one makes a manifold with EGR, could I run some kind of external EGR setup? I have some pretty shifty smog check places around here, so I'm thinking I could probably get by without being 100% kosher. Thanks!

 

I am selling everything you would need to do a swap if you are interested check out this site. Had it on my LT1 for a very short time.

http://geocities.com/rickyzZ28/