Just wondering if an LT1 can be carb. out. Please do not flame me for my lack of knowledge.

well isnt lt1 the intake? If it is now it can not cause once u take the lt1 off then what is it? Just a engine.

arent the heads sort of unique to the engine too? i dont know, just a thought, but besides which, mostly he is asking if you can use a carb on it, i say not likely with that reverse cooling stuff, but that might be intake related only too, i dont know my lt1's

I swear I have seen a carb intake for an LT1, but I think you would still need a computer to run the opti spark.

having a carb on an LT1 kinda defeats the purpose. it would be easier to just drop in a carbed 350 and sell the LT1, you may even make some money that way.

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'86 IROC 5-speed
305 LG4
edelbrock performer rpm intake
edelbrock 600 cfm carb
msd pro billet hei distributer
'95 3.23 rearend
hotchkis rear suspension
PST front polygraphite suspension
"speed kills. buy a f@&d, live forever."

I have seen someone with a carbed lt1, he still had the cam driven water pump, It was interesting to see.

You can absolutely carb an LT1. You need a GM performance parts intake manifold (don't know the part number) for starters. But, it is too coastly compared to a regular SBC 350 w/ carb set-up.

I was asking because I was telling my friend that it could NOT be done. Just because the LT1 does not have a distributor or the place for a distributor. I may be maistaken though.I don't much about the LT1s. Just never seen a distributor on an LT1. Thanks for the input.

The distributor is flat aginst the front of the motor, and gear driven off the cam, it has a rotor just like HEI. (Cost around $350 bucks after market, and upward of 600-700 bucks GM)
The plug wires all run to the front, and the opti spark (offical name of the LT-1 distributor) routes the wires ends inside the opti so that wire don's have to cross over to the right or left( The driver side wires all connect the driver side of the opti, and vis versa). The firing order is the same as regular first gen 350. The water pump is also geared off the front of the motor, and it stratles the opti (A BIG MISTAKE WHEN THE WATER PUMP STARTS TO LEAK). It connects to the front of the motor just like 1st gen 350's except it requires threes bolts per side, and is rectrigular.
The cooling system is reversed, so the water is pumped into the heads first. The oil pump runs off an adaptor inside the oil gallery where a regular distributor would go.
There's more quarks like the heads have a different bolt pattern to the intake, etc etc.

I'm not saying it couldn't be carbed, but what about all the other stuff, like the computer controlled timing(opti). This engine was clearly designed for computer controll fuel injection, and that why folks the trans plant these over priced beast also trans plant the computers, and fuel injection, hell even the accesories, AC, alt as one.



Ron

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'82 Trans Am
'81 Camaro Z-28
'94 Vette LT1 Coupe

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double post


[This message has been edited by ronterry (edited October 17, 2001).]

I'm not sure if they still make it but GM part no. 24502574 is the manifold mentioned above but will fit LT4 heads ONLY. It will physically bolt onto LT1 heads but the ports will not line up...LT4 heads have taller intake ports. It does have provisions to use a standard distributor.

You could use LT4 style heads to use this intake and bolt it to the LT1 shortblock, but that would be just more money.

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1989 IROC-Z, ZZ3 shortblock with some bolt-ons.
13.20 @ 108.69, 2.2 60'

There is a GMPP carburator-specific intake manifold specifically intended for LT1 use. It also has a big hole in the back so that an HEI distributor can be mounted, where the HEI is driven off the usual drive gear at the back of the cam. All L99/LT1/LT4 engines had this drive gear because it's also used to drive the oil pump. The optispark distributor was removed and they either used a different timing cover, or they filled the holes in the stock timing cover (I don't recall which one).

Hot Rod magazine did an engine build up (with Mark McPhail) in 1999 to showcase the intake manifold and other GM Perf Parts used, and they did it using a used Buick Roadmaster iron-head LT1 engine.

They first installed a 4th gen LT1 Fcar cam, the carb intake, a carb, and an HEI dist, plus headers and mufflers. On an engine dyno they got around 360 fw hp and 380 fw ftlbs. They then did a progressive install of 1.5 GMPP roller rockers, and then 1.6 GMPP roller rockers, screw in rocker studs, and a GM LT4 HOT cam. That engine made 422 fw hp and over 410 ftlbs, and the torque stayed over 400 ftlbs for a span of at least 2000 rpm.

So there IS a manifold that is designed for carbs, and it does fit the LT1. So yes, you can use a carb on an LT1 engine.

FYI. - Ken

I have an 1986 sport coupe that had a 305 with a 5-speed.I decided to switch to a 350 and i came across a LT1 out of a 1994 camaro. So far I figured out to carb the LT1 you have to:Get a new intake manifold,summit makes a opti-spark blockoff with timing pointer on it,get an HEI distributor, run electric fuel pump and i read that there is clearance issues with a/c. The reason to use these blocks instead of the traditional 350 blocks is the roller camshaft.It may not be worth the extra money to some but I got a good deal on my motor and Im sure it will be worth it in the end

well the benifit of using the lt1 isnt just the roller block, u can get a traditional 350 roller block, its the heads flow great for stock heads, reverse flow cooling means u can run hight compression and a cpl other things, i say go for it, and o all the fuel injected boys wont like this but gm says that witht the carbed intake it increases torque by up to 30 ft lb withought sacrificing top end power


http://store.summitracing.com/partde...2&autoview=sku

thanks for the info i dont care what anyone thinks about it long as its bad *** when its done my friend told me about the heads.Really appreciate the info and Ill let u know how it goes

So i can use the traditional water pump???
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does anyone have pics ????

Im pretty sure you have to use the gear driven pump because the holes where the coolant flows through are different.Im not a 100% but thats what it seemed to look like to me.

ok.

does anyone have pics??

not yet, my motor is still on engine stand wont be ready for about 2-3 weeks to go in.Im waiting on money and parts.

The LT-1 heads do not have water passages. They have a different bolt pattern. you would have to see if you could drill the holes for an lt1 to an old style intake. then use a remote thermostat housing. you are stuck with the lt1 water pump. and the opti can be eliminated, I believe all you have to do is stick a distributor in the new manifold and go. Does the cam have the gear to run the distributor?

You dont have to drill or modify anything,there is a tube that hooks to both heads from the back and I believe it hooks to the waterpump.I bought the intake manifold from summit that is made for those heads it is from GM performance and it simply bolts right on.As far as the cooling situation goes, you just have to hook everything up almost like it was originally i believe.

cool man thanx

Any updates on this build?

Im considering something very similar because i scored the complete engine super cheap.

i actually got my motor from a wrecked camaro z28 cheap,but turned out after putting hot cam kit in,buying special intake and blockoff kit and spending money to get heads redone that the harmonic balancer must of took some of the impact from the crash and motor inevitably spun a bearing.But i did have the car running and driving and can anwser any question you might have.I also have the intake and blockoff kit which i would sell cause i sold the car to a friend and we put a regular sbc in it. I now have a 93 trans am with a lt1

i kinda sped read this thread cause im in a hurry. but after all that do you still need to redo the computer ?

If you run a regular dist in the intake you don't need a computer at all , just a power wire to dist like on old skool engines

Yeah if you run it carbed with an old school HEI the comptuer doesnt do anything but turn on the fuel pump... maybe the secondary fan. You'll need to get those sorted out but the engine is running autonomously.

Old thread.

What about the oil pump drive shaft?

yes you can, here is a photo

do you still have the intake and block off plate, Call me if you do Russ 231-342-7572

i personally have put a carb on a lt1. i works perfect. anyone that says it cant be done or run right dont have a clue! mine is in a 86 jeep cherokee i have been driving it every day for a year now with 35 inch mud tires and i get better gas milage than my stock 2000 cherokee with 33's. im getting around 18 mpg. check out my burnout on youtube, "burnout in my lt1 cherokee". i used a edelbrock 600 electric choke