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LT1 and SM465

chris12

chris12

1/2 ton status
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Apr 23, 2006
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Location
Forest Ontario, 1/4 hr from Port Huron Michigan
I have a 94 LT1 that i plan on putting in my blazer. I have a few questions.
Any way of not cutting the frame for the ACC brackets? IS there a kit you can buy?
And Wiring harness, I have the Harness from the donor car and computer. I plan on running the same tranny thats already in my truck which is a SM 465. What will i have to do for wiring?


Thanks
 
Get a standard transmission prom and hook it right up with a 10 spline clutch disk, no problem!
 
Summit sells wireing kits from Painless that are really easy. Not super cheap, but a lot easier than the harness from the donor.
 
i know a guy who swaped in a lt1 to his 4x4. he was not happy in the end. no real bottom end grunt and pain to swap in the end.

those motors tend to lend them selfs better to 2wd stuff.

and dont forget the pass side motor mount is upside down from stock if you use all lt1 stuff. thay cast a 4th boss in the block to do this. but you can swap in std style mounts. but the serp bracket or somthing is there. so thats why thay did that.

dont forget the opti sparks suck and hate water.
 
most lt1 ive run across have more than enough low end. very stout motor from the get go. i would assume that he did not have it setup right. the aftermarket opti sparts from msd and some others are very well built and hold up to water and such, (although if i was building a mud truck i wouldnt go with a computer controlled motor) i would assume this is gona be a street queen or trail truck, either of those an lt1 would be a great motor. dont waste ur money on the lt4 kit. port the heads get a cam and good exhaust and it will serve you better for the money. or if you got some extra dough do the 383 or 392 stroker kit you wont regret it! Good luck

Oh btw checkout some of the hotrod sites there is some different configurations you can get for the serp. setup.
 
I just bought an LT1 out of an 95 caprice. I didnt know I was going to have ac to frame contact? I have been searching high and low to find out if I can make this opti work in water crossings? Cant you just silicone it all up? do you have to do alot with the harness to make it work. I have so many Qs.
 
The "optispark" distributor is mounted on the front of the LT1's, roughly where the water pump is on most SBC's. It is very sensitive to water, the later model units have a vent/drain to help keep water out of it.

If water makes it under the hood its very likely that the optispark will stop throwing spark which is why many in the 4x4 world are wary of it.

I just put an MSD "optispark" into my brothers '96 Z28 but I think most of the upgrades were made in spark amperage/voltage and reliability rather than water resistance (though it supposedly gets rid of the first design's shortcomings).

LT1's have plenty of bottom end for a truck IMO.

If you can get past their mounting/wiring issues and keep the distributor dry then they are great motors for a truck.
 
If your doing water crossings i would not do the lt1 with the computer. Your gona have to many problems.
 
My LT1 had enough grunt to break a 10 bolt, thats good enough for meeeeee!
 
The "optispark" distributor is mounted on the front of the LT1's, roughly where the water pump is on most SBC's. It is very sensitive to water, the later model units have a vent/drain to help keep water out of it.

If water makes it under the hood its very likely that the optispark will stop throwing spark which is why many in the 4x4 world are wary of it.
Click to expand...

they're strong engines that can launch a c4 vette pretty dang well. torque output isn't far below an LS1. the caprice got a detuned version, i'm sure, but is probably still a decent engine. it's true that optispark hates water, but there are ways around that, such as replacing it with an aftermarket unit that mounts higher. the ones i've seen still require some components of the optispark to be used, but it's supposed to be better than stock as far as water tolerance.

have you considered mating it to a c4 vette tranny and running a divorced t-case? might be more trouble than it's worth, but it's an idea.
 
The caprice lt1's have steel heads. the camaro & vette lt1's have alum. everything else is pretty much the same.
 
I have asked this question before and never got a straight answer.
I want to silicone up the OPTI. make it as water tight as poss. I know they dont like water, and I dont want to submerge the whole truck in a lake, but it will get water splashed on it. will this work? why or why not. I need an explanation. thanks -Ryan
 
I don't think this will work. It's been awhile, but my understanding is that the earliest opti-sparks weren't vented ENOUGH, and this caused problems, so GM revised how they were vented and it cured those problems.

No way you can keep it completely air tight, so I'd imagine you'd trade off immediate failure due to submerging it, for long term corrosion issues.
 
The difference between the vented and non-vented Opti is simple:

vented- it is sealed and vacuum line pulls air through the Opti sourcing air from the engine air intake hose.

non-vented- open to atmosphere.

All "B" and "D" body engines are vented, and IIRC mid year 94-up "F" and "Y" bodies switched to vented (maybe only 95-up).
 
DO NOT SILICONE!!!! there got it good! lol sry couldnt help my self. but seriously if you silicone it up it will not function properly and trust me they are a pain to change in a camaro. i would imagine a truck would be a lot easier to get at, but still a hassle. can on the link i posted up and you'll find anything and everything you wana know bout lt1's!
 
I have an LT-1 sitting in the garage as I was going to do the same swap. After finding out about the opti-spark problem I did several months worth of research to find that it can be done fairly easily but the results are less than desirable long term in an off road truck. Everyone I talked to loved the power. The problem is that the bolt holes on the heads are different than the standard SBC configuration. Therefore you must use the accessories that came with an LT-1. They do make a A/C delete kit that will allow you to NOT notch the frame on Ebay. However I have not tried it first hand to see if it is true. I looked into swapping to a standard type distributer and it can be done. You must use an L98 computer and distributor and get your intake drilled for the distributor hole and a shim welded in place. The problem with going to the coils is that you still use the sensor in the distributor, and that's what goes out when wet. You can also just go with an aftermarket EFI computer and old style distributor and make it work as well.


All in all it can be done, but from my research and talking to people who have made the swap. To make it completely reliable around water it is expensive. I am selling my LT-1 and putting that money into my new engine I am currently building and move on. Just my opinion, but it cost more to fix the ignition problem than it is worth for 300 HP.
 
Somewhat along the intent of this post, other than induction and heads, what, if anything separates the LT1 from the first gen SBC? Is the bore/stroke different?

Only reason I mention this is that if the bore/stroke is the same, then I can't see any point in dealing with LT1's, instead of just going with some injection, good heads, and intake for a 350.

LS1 is a different story, I realize, but LT1, I thought they were pretty much a stop-gap motor, with a goofy reverse cooling design that GM got rid of immediately afterwards.
 
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