87iroctheo

I have read a few posts which elude to but do not state that removing the optispark means you no longer have to rework your harness to make an LT1 run in a 3rd gen (specifically an 87 with factory 5.7 tpi). Therefore the swap becomes a straight drop in. I am weighing the cost of full msd and mini ram (which comes with rear distributor location) vs porting lt1 intake and adding msd to the existing optispark. If swapping intakes and ignition systems saves me having to rework the harness I might be more inclined to go that route. Ps the doaner LT1 car is 1995.

aliceempire

iTrader: (14)

Eliminating the optispark how? The LT1 intake COULD be drilled so you can use a conventional distributor and then you'd be able to use the factory 87 tpi harness with minor changes. That's a bunch of work to go backwards. Or build a harness to use the LT1 computer and opti. Use the LT1 computer and change to the LTCC coils to eliminate the opti. Or convert to a LS1 pcm and go individual coils. In any case you have to rework a harness or pay someone to do it for you.

87iroctheo

I thought if I went with the rear rotor distributor and full msd ignition setup there would be no need for optispark and the factory harness would just wire straight up. If that's not the case then, I don't see much benefit of going to the mini ram when a ported lt1 I take will meet my power goals. Thanks for the reply aliceempire.

aliceempire

iTrader: (14)

Using the conventional distributor and tpi harness on a LT1 has been done and doesn't take a lot of rewiring but you'd loose the bonus of sequential fuel injection and you'd still need to fab the intake for the distributor hole and possibly clearance if your still using the large cap distributor. May as well stay with a SBC gen1. Do a search on the classified and you might find a modified LT1 intake in short order. They'll be cheaper than a miniram but you will have to setup a remote thermostat. Good luck in whatever you do.

five7kid

iTrader: (14)

What are you trying to accomplish, eliminating the Optispark, improving the Optispark, or using the TPI ECM to control the LT1?

The biggest knock on the Opti is its susceptibility to damage from a leaking water pump. Two things can improve that situation: 1) vent the Opti (guess what - '95 is vented from the factory); 2) eliminate the possibility of the water pump leaking onto the Opti (done via an electric water pump).

If you want the power advantages of the LT1 with the simplicity of using the existing TPI system, then another alternative is to do a Vortec head swap with an improved intake like the Stealth Ram.

camarokeith

My goal isn't to simply to eliminate the optispark. My research tells me I have nothing to worry about, seems the majority of issues Are created by water from car wash or rain etc and I don't see myself having issues avoiding either of those scenarios. My goal is to make my swap as easy and cost effective as possible. So after reading that a rear mount dist eliminates the need for reworking a wiring harness, I though with the money a guy saves from not needing to buy a harness (not sure I have the time to tackle making my own) plus the cost of getting a little work done on the stock intake, i would be almost at the same cost of going with a mini ram (which has provision for rear mount dist already). The sequential fuel injection is new to me. I have read many many L98 vs LT1 which is better, and none of them take a pro vs con approach to the comparison, they seem to always simply state one or the other because of a single reason. Basically the way I see it, if I have to do any rewiring I may as well keep the LT1 stock intake and optispark.

WhiteBlaze

iTrader: (1)

Is the intake for an LT1 or a sbc? If its for a sbc, you also have to look into the the fact that the sbc manifold has provisions for the thermostat housing. Don't think it would be too much of an issue, but its something to be aware of.

Pocket

iTrader: (24)

Mounting a distributor on a LT1 does allow the old TPI harness to be reused with some minor tweaks. I wouldnt advise it though. Most people look to adapter the newer tech onto the older engine, not the other way around

camarokeith

Makes sense thanks for the responses everyone. I will stick with stock intake and optispark.

thebandit50187

so you have a LT1 swapped IROC? putting distributor in a 4th gen isnt easy. basically have to pull the motor to do the work. IF you have a LT1 in a 3rd gen then you already have a modified harness. if you have a L98 then you dont have an optispark. L98 vs LT1 is easy to compare pro and cons. similiar motors minus intake manifold, reverse cooling and ECM's. a mini ram on a L98 will produce similiar horsepower numbers to a LT1 because the cam specs are about the same and the heads flow about the same too. either a mini ram L98 or LT1 will gain HP and TQ if switched to a 24X or LS1 pcm setup and youll lose the optispark issues. but optisparks in my experience arent as bad as people say they are, but they are pricey

novaderrik

the optispark is an amazing system that puts the cam and crankshaft position sensors in one spot that is driven right off the front of the camshaft..

honestly, that's the only really revolutionary thing about those engines, other than the reverse cooling which couldn't have been that great of an idea since GM went back to standard coolant routing with the gen3 engines. but it is an upgrade over a TPI engine, for sure. they make all the torque that the TPI does down low while also breathing well enough to make power up past 6000rpm.