I've got an opportunity to get an LT1 out of a 94 Firebird after it's swapped for an LS1 in the spring for a few hundred bucks. I was going to drop the LT1 in my Firebird but wanted to be prepared first. I started off by doing searches and reading some of the Sticky Threads already. I know there's a ton of info on here but it's mainly fuel injected swaps.

My car was previously swapped from v6 to LG4 carb'd v8 before I bought it. I have shorty headers on the car that I will plan on reusing and I'm going to carb the Lt1 so that will entail getting a new intake, carb, and distributor to do without the computer. Is there anything else to worry about with my current computer or wiring harness? I'm also keeping my electric fan for the swap and the 700r4 tranny.

I just wanted some clarification from people that have swapped the LT1 into the third gens on common problems I will run into. I read that brake lines, exhaust piping, hood clearance, and motor mounts seemed to be common but I'm not sure why or if these are a definate problem.

I could have a shop put the motor in for another $400 but this swap didn't seem that bad if I've got help and I'm not rewiring a new harness and computer.

The guy I'm getting the LT1 from wants to race me after we get the LT1 in my car and the LS1 in his 94. Any chance I'd win with my third gen with 3.43 gears? I wasn't planning on doing much performance wise pre-swap but maybe a new cam.

 

Why, oh why, would you want to put a carb on it?????

I just don't get it.

If you want to come close to the LS1, you're going to need a mighty healthy cam (and that's assuming he doesn't do anything to the LS1).

 

1) dont carb it, keeping the fuel injection isnt that big of a task.

2) theres nothing about prepping/dropping the motor that is too difficult to where you have to pay someone 400 to do. Just really tedious.

3) Havent heard of any hood clearance issues, as far as motor mounts, reuse stock clamshells, but replace the mount bushings.

Research, research, and research some more.

 

The hood clearance issue was a concern because of the carb and filter sitting on top with the stock hood.

Any motor I put in will be carb'd. I just don't want to deal with buying a putting in a new computer and it's just a preference of mine. I'm between taking this LT1 and using a vortec 350 truck motor. Any input?

Either of these should just bolt right up to the 700r4 from what I've read. I don't quite understand what Optispark is on the LT1 but I know I won't use it if I go carbed but is there anything that has to be done to delete it? I don't know if the GMPP LT1 carb intake does that or if there is something else to do.


Any feedback on the brakeline issues? I keep seeing them in posts but I don't understand what specifically the problem is.

 

Put the carb on the Vortec. Putting a carb on the LT1 and eliminating the computer and Opti just doesn't make any sense.

I don't know what brake line issue there would be for a V8 to V8 swap. V6 to V8, you need to move the RF brake line on the K-member.

 

Optispark gets removed in a LT1 carb setup. An optispark delete cover plate replaces the optispark. The cover has a timing pointer on it. An aftermarket LT1 balancer with timing marks is then needed because the stock balancer doesn't have any marks.

Parts needed are:
1) LT1 Optispark Delete Plate (GM 12367600)
http://www.summitracing.com/parts/NAL-12367600/
2) Lt1 Aftermarket Balancer such as Professional Products 80030 (can be found for under or around $100 shipped on ebay) There are also other balancers but this one is the least expensive.

 

FiveSeven, I always try to take your advice because you're extremely knowledgable but just curious as to why you think the LT1 is a waste and doesnt make sense if I could pick it up for $300 or so. I can't find a low mileage Vortec around that price.

Thanks Firebat for the prices and part numbers!

 

Wow, I just had an enlightening moment and now I feel dumb. I have a mechanical fuel pump...I don't want to switch to an electric fuel pump.

So now the question is what motors am I limited to that will still have a spot for a mechanical fuel pump? LT1 is out of the question and I think the newer Vortec 350s are too if I'm not mistaken. Am I limited to old 350s that put out 200HP? If that's the case I need to rethink a lot of things.

 

i still dont understand why you would carb an lt1. but now you want to keep a mechanical fuel pump to. just out of curiosity are you just unknowledgable about electronics so dont want to put in something you cant fix.

 

keeping the FI is very easy to do, since you have everything there. wouldn't the engine come with the computer and the wire harness? What side do your fuel lines come out on? what did you do about the fuel pump that was in the tank when it used to be a V6? If you have the lines that come out on the Driver's side, and the electric pump is still in the tank. All you need to do is have a wire harness mated with the 3rd gen one, and a set of fuel lines made to bridge the gap. The biggest hurtle that I had to jump was makeing it so the A/C fit. Fuel Injection is the best for power and fuel economy. If you aren't building the engine up you don't need to tune the computer either.

 

Exactly. I like simple. I bought this car to have a project that wasn't too complicated with electronics. No power windows, locks, etc. The wiring is still a mess from the last swap. It's not that I couldn't figure out how to do the electronic stuff, I work with electronics all day at work and have rebuilt computers but I'm just sick of electronics when I get home and wanted something basic and old school.

Yes, the engine would come with the computer.
My fuel line comes up the driver's side and then turns at the front end over to the passenger side and up to the carb. I have no idea if the electric pump is still in the tank because I didn't do the first swap. I bought the car with the 305 in it. It was a very messy looking swap and that's part of why I don't want to depend on anything they may have messed up with wiring. I've had a lot of headaches just to this point. I have no idea if that pump would work but I don't want to drop the tank to fix it. I suppose your idea of having the wire harness mated to the third gen one is the best way to go but it's extra cost and as I stated before I was trying to get rid of most the computer dependability and have a simple mechanical car.

 

"Simple" to me would be to install the LT1 with EFI. Electric fuel pump is a piece of cake.

But, if you really want carb and mechanical fuel pump (notice how many "competition" set-ups have a mechanical fuel pump?), then go with a Gen I short block and Vortec heads.

 

Any idea what kind of numbers I'd be putting out with that setup?

I'm guessing I won't find a roller 350 with the spot for a mechanical fuel pump right?

 

Yes, you can get a Gen I SBC roller cam with the fuel pump lobe.

Power depends upon what exactly you put together - which Vortec-style heads, what cam, what induction, exhaust, etc.

 

Which applications were they used in?
The only factory hydraulic roller cam 350's that I know of were out of the later third gen f-bodies, late 80s corvettes and 96+ trucks? Is there any other application that I don't know about?

From what I've read so far, some of the 87-95 truck motors are drilled to work with a mechanical fuel pump and are just blocked off with a plate and some it can bolt up to but there aren't cam provisions for the lifter. Most those motors are flat tappet though.
The 96+ truck motors typically aren't compatible with a mechanical pump.

I'm just confused as to what block I'm looking for and what it could have come out of. Any help here is much appreciated. I suppose I could go with an inline electric pump with a regulator as opposed to an in-tank pump being that I'm running a carb and low pressure right?

 

all of the 350s after 87 have the holes to make it a roller setup. if you're looking for power then you'll need a cam anyways, just get one with the fuel pump lobe on it. comp sells this kit http://cgi.ebay.com/ebaymotors/COMP-...item45fc6d505a. then you need the lifters, correct timing gear set, and correct length pushrods.

 

I agree with you wanting to keep it simple. I am trying to do the same thing with my 88 2.8L. I've got a 305 for free in running conditon it is originally out of a late 70's firebird i beleive. You said your first swap wasn't done neatly. Any suggestions?

 

LT1's have D shaped exhaust ports so you need headers for that

the 94 transnission was the 4L60E so the computer will want to control the tranny. the 700R4 will work but me thinks speedometer might be an issue

the LT1 is a decent engine and with bolt ons it makes well over 300 FWHP. With a cam and bolt ons you can match a bolt on LS1. But, you need headwork and a cam to run with a cam only LS1

Bolt-ons, makes over 300FWHP and will run all day and give ok economy is not a bad thing for a 20 year old engine. (92 vette introduction)

 

This is looking more expensive to find a 350 and retrofit it to work with a roller cam than to just use the LT1. If I just use the LT1 and delete the optispark could I use one of the low pressure universal electric fuel pumps with the carb and just run it that way?

I didn't do the first swap, I bought it with the 305 in it. I would say to not let disconnected wires just chill in the bay unused would be a good thing. I have a bunch of connections that I don't know what are used for just dangling.

I'm not quite sure what you're getting at with the tranny. Are you saying that because I'm not swapping the 4L60E the computer will throw codes and have problems if I try to swap the computer and keep it fuel injected? I have Hooker short tube headers on the car now that I was going to re-use. Would that work with the LT1?

 

So would my current hooker shorty headers be a problem with the d shaped exhaust ports?

Will my universal electric fuel pump idea work?