About to do a 305tpi to an LT1 350 carbureted swap in my 88 iroc. My question is which carb do you recommend for this setup?

Motor was bought from a guy that originally purchased it for his sons older nova. He was recenly diagnosed with cancer(but surviving) and decided there were to many mods needed that he didn't want to tackle in his condition so he decided to sell. Anyway, he forgot some of the details about the work but this is what I do know for sure.

1995 LT1 (w/40k from police cruiser) rebuild consists of the following:
Polished crank, all new bearings & pins
stock pistons w/new rings
12554290 cast iron heads (unspecified valve work?)
standard rockers
Not sure on the lifters?
Comp cam part#07-305-8 Xtreme Energy
GM Performance 24502574 Intake

Not the right forum but I need a rec on a distributor as well? want to eliminate the ECM as much as possible.

Thanx

 

In my opinion, you're starting with the wrong engine. The LT1 is best with EFI. Conversion to carb is an exercise in getting a square peg in a round hole.

Either run the LT1 with EFI, or sell it and get a Gen I SBC to put a carb on.

 

Damn!

Well funds are real low and can't afford an EFI setup for this. Thought this was an easy swap.

 

Please let me know what known problems I may face if I use this setup? Is there a thread somewhere with info on a similar swap?

I guess I could sell and look for another motor but I'm just curious why this won't work or won't work well?

As I said in a few previous posts It's been over 20yrs since I've done any major mods and I'm still an old school carb and headers geek. I'm laid off at the moment so funds are real low and I kinda blew my wad on this motor
Thx

 

Search the LTX/LSX subforum in the Engine Swap forum.

People have done this, but, again in my opinion, it is a solution to a problem that doesn't exist. It would be cheaper and easier to get the LT1 stuff you're missing and install the engine as an LT1 than it would be to try to use a carb on an engine that was never designed for it.

Here's another problem with the parts you have: The heads are LT1, and the intake manifold is LT4. The ports are different between LT1 and LT4, so the two can't even be used with each other.

If you want the advantages of the LT1 heads without using the LT1 control system, get a Gen I small block and put Vortec heads on it.

 

I converted my LT1 to carb its not hard. And there are alot of advantages to the LT1 over older gen1 blocks. All LT and LS engines perform very well with carbs.

But you have the wrong intake. you need 24502592, a dist. cover plate from gm performance parts, a non computer controlled distributor (don't 4get to change the distributor gear to a bronze gear if u are using a roller cam.) and a regular small block balancer (6.75" if i recall)

Its been a while since i did it so if u need more info just message me. I have the book on LT1/LT4 conversion

 

WOW!!! Thanks!
Glad to finally hear someone with a positive comment on this conversion! Just spent the last 3hrs reading thread after thread on this and man there are some real carb haters out there. I do understand there point that the gen 2 was designed fi but I'm oldschool and prefer the carb and I"m sure it will run well with it.

I did figure out today the guy that set this up has the wrong intake on there. If you look up that part #24502574 though, in the description it says LT1 performance manifold (until you read the application where it says LT4) Anyway I'm going to get the correct intake and go forth with the project

My original question though was "which carb for my setup". I was told 600-650cfm would probably work best. Mostly street driving (with the occasional romp) but probably won't be a daily driver or at least until my son gets ahold of it

Thank again and I'm sure I'll need to take you up on some info

 

Im using 750 mechanical with the choke milled off. Don't know what jet sizes, but I use mine strictly at the track. Runs perfect not too rich or lean, and power at every rpm. Actually I can't say for less than 3000 rpm cause of my converter. But im sure it will be good down there too.

600 or 650 will be good too.

 

Define "hard" and "perform".

Not if it's a factory-type roller cam.

 

[quote=five7kid;4265415]Define "hard" and "perform".

To swap from fi to carb on LT1 is simple.

Remove the intake, remove the oil pump drive, install new intake, install distributor on top as you would on a gen1 block.

Remove lt1 dist. from front timing cover and replace it with cover plate #12367600. (only fits 94-97 timing covers) this cover also has timing mark built into it. It is made to work with the regular 305/350 gen1 balancer.

Using this older balancer might cause u some pulley issues. The old TPI setup might work, but not sure. Another option is to cut off the timing mark on cover plate and use the stock LT1 balancer and pulleys.

As for performance.. The carb intake is a dual plane design which is better for bottom end power, gm claims +30 ft/lbs over the single plane stock LT1 design. I'm running mid 12's with this motor in my drag car.

 

All easily done on a Vortec-headed Gen I SBC for less cost with the same performance level.

You've put a carb on your drag car. The Gen II & III carb'd cars of which I've heard on this Board are drag cars. I don't see this as a coincidence.

 

[quote=1qk4mula;4264967]But you have the wrong intake. you need 24502592

After some more research today it looks like the 24502592 LT1 Intake has the same casting #24502574 as the LT4? See notes at the summit part http://www.summitracing.com/parts/NAL-24502592/

Since the motor was already assembled when i got it and the guy who assemled it says it's the correct intake bought direct from GM, can I assume it's correct? If it was the wrong one would it even bolt up or do the LT4 heads have the same bolt pattern with only different porting?
AAHHH!!!

 

The intake ports on lt4 heads are taller than the LT1 ports. The 592 is the part number of the intake u need. The casting number means nothing.

I don't know if the LT4 intake will bolt up, if it does and doesn't leak, u can use it.

I will check for casting numbers on mine. Do u have any numbers on urs?

 

I only see the casting # and firing order. I will look again tomorrow but i dont recall seeing any other #'s

Thx