94 Lt1 350

[Jclgodale3]

Folks...still looking for a more modern 350 for my 68 Project. Found a 94 LT1 from a Buick Roadmaster with computer and wiring. What are the differences between GM models in these later years? Need advice as I need to make a decision sooner than later...thanks:crap:

 

[Twin_Turbo]

They are all the same, except the non vette ones have iron heads.

 

[mrvette]

I assume you know about that opti spark it's the achilles heel of the LT1-4 engines in vettes, somehow not a issue in a larger car, engine set higher?? dunno, but never heard of much about that except in vettes and maybe one or two F body....

maybe there is a fix out now for that??

:drink:

 

[Jclgodale3]

maybe there is a fix out now for that??

:drink:

I've heard there is a fix for it reading some threads on another forum. I have a line on one with 65-70,000 miles for $500 with computer and harness. Good deal or not?

 

[Twin_Turbo]

The fix is a vac. line/breather line on it but it doesn't make it 100% bullet proof. Neither does the expensive MSD unit.

You could sue GM cover part # 12367600 and run a normal distributor if you either don't use the LT1 intake or convert it for a rear mount distributor.

The problem is the ozone buildup from the high power leads inside the optispark that caue it to fail, water doesn't help either. There's a couple of kits out there that convert to 4 or 8 (LS) coil packs and only use the optispark trigger.

 

[mrvette]

maybe there is a fix out now for that??

:drink:

I've heard there is a fix for it reading some threads on another forum. I have a line on one with 65-70,000 miles for $500 with computer and harness. Good deal or not?

I would think it's a good deal, and TT above has outlined everything I know of about the 'fix' for the opti crap....

for that matter, I have a LT1 induction that is highly modded to fit on my L98/ZZ4 engine, including a mounting pad for a normal chebby HEI in back...:drink:

 

[Jclgodale3]

Well, got it for $375 after bargaining with him. He gave me everything with the motor, maf, wiring harness, pcm etc. Hope to start on it soon. Now I'm ready for some budget upgrade ideas:idea:

 

[1981Z06Vette]

They are all the same, except the non vette ones have iron heads.

Not quite, there are some differences: 92-96 Vette LT1s ; aluminum heads, 4 bolt main block

93-97 F-Body (Camaro/Firebird); aluminum heads, 2 bolt main block

94-97 big cars (Caprice, Impala SS, Roadmaster, Fleetwood); iron heads, slightly milder cam, 2 bolt main block

92-93 are speed density, and use a replaceable chip/EPROM. GM changed from the Th700R4/4L60 to the 4L60E in 1994, so to run an earlier non-computer controlled overdrive you need a 920-93 throttle body (it was the TV linkage hookup), or an adapter piece from Street&Performance.

92-94 use the unvented Opti; 95-97 use the vented one. There are conversions to use Northstar or LS1 style coils (requires the LS style ECM, and a few other items to make work). The biggest issue with the LT1 is a crappy water pump; gut it and use a Mezeire electric conversion. 96-97 are OBDII, but can be converted to OBD1 (easier to program) with just a PCM change and a different knock sensor. A carb style intake was available from GM, which uses any SBC distributor (the LT1 has a short stub shaft to drive the oil pump in place of the SBC distributor).

 

[Jclgodale3]

Next question...Would you guys stick with the Multi Port injection? Or go carburated?

 

[mrvette]

Next question...Would you guys stick with the Multi Port injection? Or go carburated?

INJECTION.....easy, hands down....you got all the shit, why spend money to make a antique out of something modern....

besides, I dunno they make carb mani's for the LT engines anymore....being they outta production a dozen years now....and only made for ~6 years anyway....

:crutches:

 

[Jclgodale3]

What all did you scrap on yours? The EGR? A/C? Did you go with the old PS pump setup? Etc? Etc? I also noticed the flywheel is smaller and the bolt pattern won't fit the Turbo 400 torque converter. How did you rectify that? Thanks

 

[mrvette]

My engine is not a LT1, i'ts a L98/ZZ4, I got a welder buddy to help, and so highly modded a stock LT1 induction/mani to fit the L98 engine....I cut a dizzy pad off a old rotted out carb mani and used it, redrilled the flanges and redid the cooling passages.....I use a remote t-stat housing up front near the radiator....

except for the dizzy mods to it, that allow the L98 HEI to be used in stock position there is almost nothing about it that's really useful to you.....

I am doubtful the HEI can interface with your computer....maybe TT/Bird know....

:thumbs:

I have a '88-91? vette serp drive and a/c comp, it fits under the stock flat hood just fine....the p/s pump valve was changed to the '72 as my steering was stock when that was installed 15 years ago....
I never faced any problems with smaller flex plates and mating to earlier trannies....my car was born with a Muncie and went auto as it was the cheepest way to get overdrive for the higher speeds/longer distances we do here in Florida....in Wash DC it's not needed too badly...