Iroc87

Okay after reading the posts about swapping an LT1 I still have some questions, here goes
1 Will any LT1 intake work or does it have to be the same year as the engine or PCM
2 Will any of the TPI accessories i.e A/C compressor, alternator work with the LT1 if not why
3 Can I use my existing trans (700R4) do I have to change Torque converters or will the existing one work
4 Will the LB9 throttle body work or do I need one for the LT1
5 TV cable can I use a 93 LT1 bracket or do I have to custom make one and what TV cable do I need to use
BTW the car is an LB9 1987 Iroc with auto. Thanks for any info you can provide

Markolc

1. Any LT1 motor/computer will work fine with each other.
2. Your TPI accessories will not bolt to the LT1 motor, because the LT1 has different bracketry because the balancer is a bit more recessed into the motor.
3. Your current tranny will be fine.
4. Your TPI TB will work fine
5. You must use the '93 bracket to be able to use the TV cable. And your stock TV cable will be fine, you just might have to shorten the tv cable slightly (just get core wire stoppers, like a $.99 part from autozone or napa).

jmd

iTrader: (4)

Your cheapest, easiest, and best (by far) is to get a COMPLETE LT1 from a donor vehicled and quit worrying about retaining your TPI parts.

That being said;

1 - some fuel rails (92/93?) had the crossover in the back; later ones have it over the plenum.

2 - TPI Accessories bolt to the LT1 just fine; the problem is that there is not a water pump / idler in the middle, which is why they do not work. Jagsthatrun was working on an idler so as to use the TPI accessories on the LT1, but since all the LT1 accessories require is a ding to the subframe, and have a tight AC to motor mount location, just use them.

3 - 92 and 93 LT1's were batchfire and not as "good" as the 94-up LT1's which were sequential fire. But, the 92 & 93 LT1's used the TV cable equipped 4L60, which is for all intents and purposes a 700-R4 (same TV cable and TCC hookup and size etc. etc.) Beyond that, I like the 4L60-E's I've driven better than the non electronic 700's and 4L60's so I will be going w/ a 94-up drivetrain instead of the 93-down stuff. Again, you have no advantage to running the older trans.

The LT1 swap w/ a complete factory harness and a 4L60-E is a wonderful thing. A friend has one running in a 1987 442 and it is a smooth, beautiful car, now that the 307 is gone.

Z28ricer

iTrader: (2)

Yes the 92-93's used a crossover in the rear and the 94' up intake is better with the crossover in the front, the accessories will not work cause like previously mentioned the crank is stuck out more or was stuck in, trust me wont work, i did a lot of hacking to just find that out, the 94 up being better is debatable so dont just go by what your told, 93 is strictly SD and when you get into a seriously built motor i've been told you'd end up deleting the MAF in the program anyway, and you can use the 93' bracket for your trans. cable etc on all year intakes.

jmd

iTrader: (4)

The LT1 balancer is bolted to an adapter which is pressed onto an 86-up crank. That is not an LT1 crank. It is an 86-up crank.

The crank is not more in and out, the balancer and it's adapter are. There are 2 adapters. One is F / B-body, the Y-body has a different one.

So since the heads have the accessory holes, and the crank could take a normal balancer, what would prevent you from using the accessories, if the water pump pulley or an idler there were present? Nothing.

94-up is a faster computer with sequential fire. If you can tell me what makes a 93 ecm better, i'm all ears. Deleting the MAF is not in the realm for a street LT1; the MAF is nowhere near the restriction people make it out to be.

Read up on the 95 Helms where it talks about certain situations and the system *reverting* to batch fire and "this will result in a major loss of power" and then tell me batch is better.

thanks

Z28ricer

iTrader: (2)

Swapping the balancer would probably require rebalancing the engine, then the pass side bracket has to be extensively hacked to fit on the block and if I remember right some of the bolt holes were missing. Why is a 94 up gonna run worse in SD ? duh cause it was meant to be maf, tell me SD is worse when the same engines made the same power (93-95 LT1 f body = 275 HP), some situations not having the maf does have its advantages (blower/turbo).

jmd

iTrader: (4)

So a 3.48 stroke motor with 4.00 slugs and 5.7 rods will require rebalancing if you use a balancer from a 3.48 stroke motor with 4.00 slugs and 5.7 rods? Think again.

Why does a MAF motor run worse in limp home? hehe. Tha'ts how Street & Performance runs a lot of 94-ups, so don't ask them. Just disconnect your MAF on an 85-89 and see how it runs.

If you really think a 93 & 94 motor make the exact same power and emissions and drivability (peak power numbers are telling, but not about everything...) well, you're wrong. Believe in Uncle Helms, not me.

Yeah I know. Buy into the SD being better theory. I'm gonna let you have that one. Not worth it.

Z28ricer

iTrader: (2)

Taken from: http://www.9c1.com/technical/LT1_rebuild/ar99928.htm

"350- The crank for the LT1 looks just like the one in the late 350 and has the same casting number 14088526, but it's balanced for the lightweight pistons that were installed in the LT1. Be sure to keep these cranks seperate so they dont end up in a regular 350, and dont ever use a regular 350 crank in an LT1, In fact, if you are short of LT1 cranks and dont have a balancing machine in your shop, you would be better off using a crank from a 305 instead of a 350 because it's actually closer to the balance specs for the LT1 crank. "

Now you're telling me the balancer is going to be OK ? I dont think so, and im not even gonna bother arguing with you on the ecm, stock programming your right a swap would be better of with MAF, but we'll see how I do on a 93' mmmkay ?