LT1 in 70 Chevelle

Thanks for the input guys. I appreciate it. However, my project is about to take a pretty sharp turn. I have almost everything I need for a TBI install, but came across a whole lt1 setup, engine/4l60e, with harness and pcm for about $400. It has about 150k on it. Supposedly it was running good when pulled so I'm hoping for the best. Is there maybe any quirks I should lookout for engine/pcm wise with this install? Should I make a new thread for these questions? I'm sure I'll have many more that come up.
This should all be going into my 70 chevelle that's been sitting in a barn for more than 20 years now.

Already moved this post for ya!

No real quirks with the PCM... it's a flash unit and no chipping. Simple ALDL cable and a $20 program from TunerCat called WInFlash.

Cooling system is reverse on those. Maybe before install look at waterpump seal as 150K they are leaking if it and OptiSpark has not been replaced.

Sweet find! :thumbsup:

What did the LT1 come out of and what year? They have significant changes for different models/years.

If the motor is in good shape, $400 sounds like a pretty good deal. As a personal opinion they are a good motor, and the optispark issues people typically complain of can be remedied and made very reliable. Also because the motor is compact, going into a 70 chevelle working on it will be much easier than a 4th gen Fbody.

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Originally Posted by bentrod

What did the LT1 come out of and what year? They have significant changes for different models/years.

If the motor is in good shape, $400 sounds like a pretty good deal. As a personal opinion they are a good motor, and the optispark issues people typically complain of can be remedied and made very reliable. Also because the motor is compact, going into a 70 chevelle working on it will be much easier than a 4th gen Fbody.

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Agreed... significant differences in LT1 pcms.

'92 - '93 Would be from a Y-body or F-body ('93 only). You would be burning chips vs. flashing the pcm. Note however that these pcms are worth around $300 alone and the Prom another $100 or so. Engine would have aluminum heads, but would have older non-vented opti-spark.

'94-'95 Would be flash based pcm and engine could have either aluminum heads or cast iron heads (only if from B-body). Could have vented or non-vented Opti-spark depending on what it came out of and/or build date. Vented opti-sparks tend to be more reliable.

'96 Would be flash based OBD2 pcm and engine could have either aluminum or cast iron heads (if from B-body). I believe all '96 and later LT1's have vented Opti-spark. Programming hardware typically more expensive in this case and some packages do not support this pcm (at least when I was buying...).

'97 Would be same as above except all would have aluminum heads since the B-body was no longer being built.


Beware: There are "baby LT1s" out there which I believe was "L99". It was a smaller displacement (4.3L) and I believe 200HP version. It looks identical to the LT1 so it can be easily confused. These came in '94 - '96 Caprice sedans.

I would personally be much more inclined to put an LT1 in vs. the TBI, especially for the deal you are getting. Of course another great choice might be a 5.3L out of a Silverado or similar. They can be had very cheap, make good power and they last forever.

Just my $0.02

Todd