1975 Corvette LT48

[Guest yatsen]

I can get my hands on a 1975 LT48. But is it worth the trouble? According to Chevrolet specs it produces a pathetic 165HP @ 3800rpm. Does anyone have experience with this type of engine? I suspect it would take a lot of work and $$$ would it take to make it less embarrassing. Am I correct?

[Guest Hudson's Hawk]

You can get more hp out of your 6 then that....Smell the NOS. 8)

[Scottie-GNZ]

IMHO, I would not waste time and $$$ with this engine. Do not get caught up in the hype that it came out of a Vette as this is a classic case of not all V-8s being born equal. Now, it depends on what your HP and performance goals are and if this engine with some minor low-buck tweaks will do it for you, then you are better off with a mild L28ET. If you want lots more, then the $$$ you will spend is best spent on finding an LT1 or LS1 bargain.

[Guest Z-rific]

As with any 350, it has potential to pump some strong HP. It just requires more money to get you there. If you were planning on getting some new heads and rebuilding the engine (cam, pistons, etc.) than youll be replacing the parts that keep this engine tame.

 

If you are not planning this kind of engine build-up, pass on it. Something better will come along.

[Guest yatsen]

I'm shooting for 300 streetable RWHP, which roughly translates to 375 at the crank. Is it possible to mate an LT1 to a TH200-4R?

 

BTW, I found some info on a board that made me think carefully before attempting such a swap ("the downside" is particularly interesting):

 

 

 

Hey, the LT-1 (I assume you mean the 1992-1996 fuel injected version) is a great motor.

I have NEVER installed one in a C3. However, I have installed several of them in other types of vehicles.

Here is what I can tell you.

It bolts up much like a standard small block. You will need to make sure that the flywheel is from the LT-1 to avoid vibration issues. The only place you will run into problems is on the front pulley system.

Street and Performance, March Performance, and a handful of other companies make accessory brackets for the LT1. I am pretty sure you can use the stock 92-96 Vette brackets. The problem with the F-body (camaro/firebird) is they put the a/c down low causing clearance problems with the cross member.

Remember, you will need a high pressure electric fuel pump and supporting wire harness/computer to run the engine.

There are two types of LT1 engines. The 92-93 use a very basic computer and can be "chipped" to run in your C3. The 94-96 engines use a more sophisticated computer (OBD II) that has to be reprogrammed. They also use sequential fire injection instead of batch fire.

This is where it gets expensive. The newer LT1 is superior to the older, but the harness ranges from $500 to $750 and requires either a lap top computer and software, or a minimum of $250 to send the computer out to be reprogrammed. You can do the older version for about $350 on the harness and about $200 for the chip.

Here is the downside. The computer will be tricked into thinking it is still in the donor car. It will not be getting inputs from wheel sensors, antilock brakes, quad 02 sensors etc. You will be running at the most basic level of ability. Most systems also require running as a speed density (no mass air flow sensor). The lack of the mass air flow sensor and running as speed density causes you to loose some hsp and create a few driveability issues. You won't get the factory adverstised fuel economy as a C4 with the same engine as the computer will be running it on the rich side most of the time.

For the most part, it is better than just running a carb. However, by the time you buy the engine, brackets, replace the ignition, special fuel lines, etc. etc. you could have installed a sweet big block that will kick the tail out of the LT1. Plus, the LT1 does not have the visual appeal of the old L98 Tuned Port engine. However, when geared right, the LT1 will run circles around the L98.

Electric fans are no problem. You will not run into any clearance issues with the radiator. You will however have to get pretty creative to route the air intake. Most guys just put the small front mount street rod air cleaner. The problem is, it is so small that it chokes the engine. You will need to get some custom 3.5" mandrel bent tube to run from the throttle body intake to a remote area with a larger air filter.

If you do decide to do this, get back with me and I will do what I can to point you in the right direction.

Unless you get a motor for free, be prepared to drop about $5,000 to $6,500 total less any labor if you pay others to do this for you. Like I said, you can get a nice head start on a big block or ready to go crate motor for that kind of $$$$$$$.

 

source: http://www.corvetteactioncenter.com/forums/showthread.php?s=&threadid=4646&highlight=LT1+AND+swap

[Scottie-GNZ]

Yatsen,

 

that is one opinion. There are numerous LT1 and LS1 swaps on this forum specific to the Z car so if you want to go that route there is no guessing game or shortage of information or help.

 

Do a search in the V8 forum for LT1 and LS1 and Th200R4 in the drivetrain section and you will be reading for a week.