Guest Draken Posted November 11, 2002 Share Posted November 11, 2002 Hey guys, I'm in the planning stages of my project and am leaning towards the LT1 SBC. I have several questions such as: 1) What do I need to know about the sensors,like MAF and computers ? 2) Since my Z is smog exempt do I have to bother with all the smog equipment (ie cat converter) ? 3) If so, will that cause a problem with engine functions or settings ? 4) Why do people delete or replace their optispark distibutors ? 5) Would wiring be considerably easier, being that I'm not good at it, if I were to use an aftermarket wiring setup (ie Painless Kit)? 6) Are there any problems that occur when installing an LT1 v. an older 350? I know this is a lot of questions but I figure I should ask them all while I'm still putting the project together. Thanks guys. Quote Link to comment Share on other sites More sharing options...
Tim240z Posted November 11, 2002 Share Posted November 11, 2002 Sorry double posted...see below Quote Link to comment Share on other sites More sharing options...
Tim240z Posted November 11, 2002 Share Posted November 11, 2002 Well, lets just say that if I can do it, any moron can! 1) You don't really have to know anything about the sensors, just basics on why they are there, and where they go. 2)If your car didn't come with a CAT, don't put one on. It will be a fire hazard. I took off all the EGR and air pump stuff. 3)People get rid of the Optispark because they are expensive to replace. They have an undeserved reputation IMHO. I know of several LT1 cars, well in excess of 100k miles with no OS issues. 4) Don't buy the painless kit. It is way overpriced and with Factory Service manual in hand, you can do it yourself. I don't consider myself to be all that adept at wiring, and although it took me a while, I did it myself and have recently fired the engine. 5) I am using TunerCat software to edit the PCM, and FreeScan to read the trouble codes. Hope this helps. Timh Quote Link to comment Share on other sites More sharing options...
Guest Draken Posted November 12, 2002 Share Posted November 12, 2002 Thanks for the help guys Quote Link to comment Share on other sites More sharing options...
Mudge Posted November 12, 2002 Share Posted November 12, 2002 The 95-97 Optispark is a pretty good unit, the others have a gaping hole in the back where the cam splined shaft goes into the Opti, and coolant/oil can get inside easily, plus the 95+ Opti has vacuum hoses to try and keep moisture out. If you get a 95 or earlier LT1, you can avoid the CAT easily. If you get a 96-97 OBD II LT1, you need to get an OBD I PCM, or simply get some O2 sims to lie to the computer, but programming and OBD II computer is alot more expensive regardless, so I'd go with an OBD I PCM from an earlier LT1 car. The 95+ Optispark is I believe $159 last time I checked, which is better than the earlier Opti cost, and some dealers charge $319 or so to sell the item to you, it all depends where you shop. Quote Link to comment Share on other sites More sharing options...
Guest JAMIE T Posted November 16, 2002 Share Posted November 16, 2002 Converting a -'94 LT1 to the later opti is actually pretty expensive. It's not the opti that is expensive, it's the small things that add up. You need a new timing cover, Opti harness, and a few other odds and ends. If you can locate the Harness and TC used for cheap, then it would be an OK modification, otherwise, it's not worth it. I've got a '94 Z28, and just went through all this a few months ago when my Opti went bad. After MUCH research, I decided to use the '94 style opti. I even had the timing cover off to replace the cam(LT4 HOT cam). BTW, my Z28 makes 341RWHP Quote Link to comment Share on other sites More sharing options...
Guest Draken Posted November 17, 2002 Share Posted November 17, 2002 I've been thinking about using a 95+ LT1 as my weapon of choice. I have heard that the 95+ LT1 OptiSpark changed in design. Considering costs, would converting the LT1 to an LT4 yield considerable power? Quote Link to comment Share on other sites More sharing options...
Mudge Posted November 17, 2002 Share Posted November 17, 2002 The LT4 made 330 crank HP, not a big deal. It had better heads (about $1150 assembled, not worth it), better intake (raised runner for both), and a small cam. The LT4 HOTCAM was not the same as the standard LT4 cam. Port your heads and run a better cam if you want power. Yes, the 95 and up opti is much better, you need a timing cover, new Opti wiring harness (one setup of wires which plugs into the wiring harness), and vacuum lines to the TB ducting, which means new TB ducting or just cut your own holes with a punch. It basically has better sealing, and is rebuildable, otherwise it performs the same function. Quote Link to comment Share on other sites More sharing options...
Mudge Posted November 18, 2002 Share Posted November 18, 2002 The 94 Opti sucks with or without the vacuum harness, but yes, you can hack it into place yourself. The Vette guys were doing this early on as well. Quote Link to comment Share on other sites More sharing options...
VRJoe Posted November 18, 2002 Share Posted November 18, 2002 I read someplace the Pep Boys had a replacement set for the '94 Optispark that had the vacuum port on it. I went over to Pep Boys and sure enough the '94 replacement cover had the vacuum line port on it, but I believe it was plugged. Cost was aroung $180, so I may just get one, drill out the plug and set up the vacuum lines. A lot simpler than modifing a '94 for vacuum or changing to a '95. -Joe Quote Link to comment Share on other sites More sharing options...
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