TPI vs LT1

[lazygaurd]

I have been looking at doing a TPI transplant out of an Iroc, into my 2 wheel blazer. Now an opportunity to buy a 96 Capprice 9C1 (police special) with the 5.7 LT1 has come up. This car would provide the the 5.7, 700r4 as well as a rear disc brake set up all in a running driving car for $2400.00 I know this is a good deal but the motor has 100000 miles and the conversion is a more involved than a TPI from what I have been told. Is there any benifits to the LT1 as apposed to the TPI or vise versa? I forgot to mention the LT1 is supposed to be chipped to 375 hp but that is unconfirmed. I was told it had a 373 posi which it doesn't, because I stood on the gas last night and only one side broke loose and I looked up the Vin and they only came with 308 limited slip. Any input would be appreciated.
Thanks Darrell...

[Deuce]

I've done the TPI and it was pretty easy. The biggest PITA was the fuel system which won't be a big deal for you as you already have a blazer tank installed.
I've heard the LT1 was more involved.

[FirstGen]

The LT1 is a much better performing motor out of the box. It has a decent set of aluminum heads factory and the wiring is much more simple than the LS1 motors. If you are interested in the performance of each motor, you will be happier with the LT1. The doubt you will want the rear end for your blazer. You may want to grab the disc setup off it but the 10 bolt rear end is garbage in the LT1, not to mention you will spend a lot of time getting it to work under your blazer and then end up with a rear end that is much narrower than you need...
Just some food for thought.

[chevyguy_72]

I have been going through the same issue. I at one time wanted to go LS1 but am now looking for an IROC for the TPI. What else is required off the TPI donor? (wiring, etc.) also what years are good donors? All this info is great
Thanks for starting the thread

[lazygaurd]

Firstgen.

I believe the Caprice uses a 12 bolt rear end and it has the 5 on 5 bolt pattern same as the trucks. The center caps on the car rallies are the same as the truck rallies as well. I didn't measure the width to be determine if that was close or not. I could be wrong but I think they used the heavy duty running gear because of the size and weight of the Caprice and Impalla ss.
Darrell.....

[GMC71k20]

the caprice and impala lt1s didnt come with aluminum heads.
tuning to get 375hp out of a lt1 is a stretch.

[70rs/ss]

I think it is still a 10 bolt, but the 5 on 5 is correct. I have an LT1 and the tranny is the 4L60E not 700R4. I had my motor, trans, wiring, and computer complete up for sale for $1000 and no takers (I still have it). The 100,000 is no biggy at least on mine because it was run on propane (AZ has a clean air act in the metropolitan areas and cop cars all run on propane) Propane does not dilute the oil nor does it deposit carbon on the valves. It is a slick set up and the harness can be trimmed down to eliminate the emissions stuff as well as the reprogramming the comp for more power. Way better than the TPI, but not as good as the LSI (but way cheaper!)

[70rs/ss]

I forgot to add that my LT1 has a completely gone through set of aluminums off of a vette (new guides, valves, and valve job)

[neonlarry]

Advantages to LT1 are it doesn't run out of breath at 5000rpm like the TPI.
One thing that is almost a must especially with 100K on it is to rebuild the opti spark system or replace with an aftermarket unit(before you put it in your truck).

[Wootdog]

The person to ask about both is Lambert at Street and Performance in Mena, Arkansas. The number is (479)394-5711. He has all the specs and information you would need. And it is possible to get alot of power out of an LT1. My Street and Performance LT1 is supposed to put out 480 HP. Kerry

[FirstGen]

Kerry is right. Just don't have a small pocket book when you call up S&P...

[Ackattack]

I put a TPI in my truck over the summer. I went with the TPI because of the "great low end torque". Well I've been severaly disappointed with the low end torque. Additionally the gas mileage from it has also sucked. I got 15mpg one tank and 12.5 two other tanks (only ran through 3 tanks so far). This is with a newly rebuilt 700r4. Heck, I was getting 11.5 with the carbed 327 and TH350 I was running.

I'm going to swap to a 3.73 rear gear. That will help the power issue, and hopefully will actually help out the mileage a little (I think the 3.08 with the OD is a bitt too tall for it)

The big drawback of the LT1 is the optispark IMHO. That's just one small issue though. It is a better engine, and it sounds like you have a line on a good deal.

I got my TPI out of a s-10 blazer. I bought the blazer for $2k, swapped out the engine for my old 327, and sold it for the same $2k, so other than some small little parts it was pretty cheap that way (tranny ended up being $1500 though )

[1971custom]

has any one done the irock camaro conversion to a 1991 suburbion that has tbi