Chevy LT1 Q&A

[DirtyLittleSecret]

So now I've got a really good deal waiting on a 1994 LT1 with 112k miles from my brother. He's got too many projects and Im in the market for a swap.
What are some of the best/worst considerations regarding the LT1 motor itself? I know its a 350, but its got alot of interesting design features. Anything I should be aware of? What kind of mpg are these producing?
Its between this and a 6.2...

 

[zombiekiller]

i've swapped an LT1 into a jeep before. If you plan to ford water on a regular basis, you may want to avoid the motor. The optispark is pretty quirky and hates water. you'll also want to get a flashed computer that deletes much of the emissions equipment. wiring harnesses will run 6-800 for a nice one. depending on your gearing and final programming you may have to fight through an unloading quirk that some people have when the auto trans makes the 1-2 shift. t-5 transmissions have a weak output because it is so long, be mindful if you decide to use one. may also want to check if it is a 2 bolt or 4 bolt main. in 94 the lt1s in z28s, vettes and cop cars were 4 bolt. HTH

 

[Waggoner5]

Its a great engine. The only negative is on the earlier models the distributer was subject to moisture. This was corrected in the later models and I have run several of them in Cruisers and they are a clean, easy install.

 

[zombiekiller]

Its a great engine. The only negative is on the earlier models the distributer was subject to moisture. This was corrected in the later models and I have run several of them in Cruisers and they are a clean, easy install.

crap that is a clean install! looks much nicer than shoehorning one into a cherokee! did you have any issues with the exhaust manifolds clearing the framerails? what manifolds did you use?

 

[Waggoner5]

In that install I used block hugger headers Jet Hot coated. No issues with clearance.

 

[ToyotaDon]

Anybody ever use an Opti-spark eliminator system?
Here's an interesting discussion. http://impalassforum.com/cgi-bin/ultimatebb.cgi?ubb=get_topic;f=1;t=007966;p=
We did have some problems with Opti-spark when I was still at the Chevy dealer.

 

[Waggoner5]

I got tired of messing with an early Optispark and went distributorless with Electromotive.

 

[brokenparts]

Its a great engine. The only negative is on the earlier models the distributer was subject to moisture. This was corrected in the later models and I have run several of them in Cruisers and they are a clean, easy install.

Now that is a clean engine bay... Wish mine looked like that.

 

[zebrabeefj40]

My DD is a stock '96 Z28 with a 6-sp. In it's current state of needing a tune-up I'm knocking down 22-24mpg on premium fuel. When it was new I would get 26+ on my daily mix of driving. The high compression of the motor kinda dictates the need for premium. It'll run on cheaper fuel but you won't get all the performance out of the motor.

Since I've just purchased most of the parts I can tell you that it's pretty expensive to do a tune-up on one of these motors. They don't use the "cheap 350" stuff that most small block Chevys use. $155 for a distributor cap and rotor (MSD brand; Advance Autoparts was about the same for cheap stuff). $250 for a GM Performance Parts timing chain set (parts store wasn't much less for a no-name timing set). $85 for Accel plug wires; the Optispark uses it's own style wire connector. You can't just buy the cheapo cut'em to fit HEI wireset and make your own (expensive cut'em yerself sets for the LT1 do exist).

The clutch is an LT1/LT4 specific part too. For the Camaro it's in the $500 and up range for a decent clutch kit. I'm not sure if one of the old school clutches will fit (like a 10 spline clutch for an SM465). If you're planning on running an auto trans that's not an issue.

I guess the Optispark can be an issue but I've got 156K miles on the original and it's still working fine. Needs a new cap, rotor and wires but I'm waiting to get the car on the lift for that. Maybe my car is one of the "good ones" that got a good Optispark unit.

IIRC the LT1 never ran a belt driven fan in a OEM application. My car uses dual electric fans on an aluminum rad. I'd guess the same radiator with the better airflow of a Cruiser engine bay would work great.

For all that it's been a great motor. Never failed to start on the coldest days. Still puts a big grin on my chin with the pedal goes down too.

Nick

 

[GAS-A-LOT!]

wow!!! who's cruiser is that? the one with all that real estate in th engine bay.?

 

[ScottFJ40]

I got tired of messing with an early Optispark and went distributorless with Electromotive.

If you don't mind me asking, what did that run you. I saw another coilpack tyoe system available in the $800 range.

My LT1 is going in now, and the optispark is a worry. I try and stay out of the wet stuff but what if it rains or snows?

 

[nikos8]

There is a couple of companies out there which partially eliminate the opti. The optical part of the otpi is still needed for the computer to function properly which to me does not solve the problem of water or snow penetrating the opti housing and leaving you stranded. The only way to totally eliminate the opti is to have the intake manifold drilled in the back and installing a regular distributor. This however means that you can no longer use your stock wiring harness and computer. You would have to move to an older (L98) computer and harness. You would also have to block the egr port in the back because the distributor would be in the way.

 

[ScottFJ40]

There is a couple of companies out there which partially eliminate the opti. The optical part of the otpi is still needed for the computer to function properly which to me does not solve the problem of water or snow penetrating the opti housing and leaving you stranded. The only way to totally eliminate the opti is to have the intake manifold drilled in the back and installing a regular distributor. This however means that you can no longer use your stock wiring harness and computer. You would have to move to an older (L98) computer and harness. You would also have to block the egr port in the back because the distributor would be in the way.

Or switch to the coil pack deal. Fix Your Opti-Spark in an Hour or Two

I think I'll just convert mine so it has a vacuum line pulling any potential moisture out.