Question: improving the 1972 LT1

[leev]

hey guys, im wondering what are the basic upgrades and what particular parts/brands do you prefer on the 1972 LT1 that can give me significant horsepower and torque gains? is it possible to bring this engine to the near 400 hp bracket perhaps? furthermore, please indicate what other things i have to replace or upgrade when upgrading a major part. thanks.

 

[6880 Mike]

The 1970 LT-1s were rated at 370hp which was understated for insurance pruposes. They were 400hp or so off the showroom floor. Build your 72 LT-1 to 1970 specs and you'll have what you're looking for without spending an arm and a leg.

 

[leev]

The 1970 LT-1s were rated at 370hp which was understated for insurance pruposes. They were 400hp or so off the showroom floor. Build your 72 LT-1 to 1970 specs and you'll have what you're looking for without spending an arm and a leg.

hey mike, could you tell me what these specs and changes are? or their differences? and what i should do when doing these changes? i cant find any detailed site showing exact details about these engines on those 2 years. :W

 

[leev]

ok ive done some research and i discovered that the main difference between the 1970 and 72 LT1 was just the compression, 11.0:1 to 9.0:1 and the 2.50'' diameter exhaust on the 1972, they had the same hi-performance camshaft and the same holley 4 barrel aluminum intake. same valve lifters, main bearings.

so i guess ill be tuning my 72 LT1 to 11.0:1 compression,
could you guys tell me how to possibly to this efficiently and im perplexed, they have the same bore and stroke at 4.00 x 3.48 so how in the world did they decrease the compression ?!?

can anyone give me a no-brainer on how to tune the 72 LT1 into the 400hp 1970 LT1 ?

 

[fine69]

ok ive done some research and i discovered that the main difference between the 1970 and 72 LT1 was just the compression, 11.0:1 to 9.0:1 and the 2.50'' diameter exhaust on the 1972, they had the same hi-performance camshaft and the same holley 4 barrel aluminum intake. same valve lifters, main bearings.

so i guess ill be tuning my 72 LT1 to 11.0:1 compression,
could you guys tell me how to possibly to this efficiently and im perplexed, they have the same bore and stroke at 4.00 x 3.48 so how in the world did they decrease the compression ?!?

can anyone give me a no-brainer on how to tune the 72 LT1 into the 400hp 1970 LT1 ?

Perhaps the combustion chamber of the cylinder heads, piston tops...?

 

[leev]

could you guys give me a little tutorial on what i need to buy and do to get this engine to near 400hp or so or in the 1970 LT1 hp

 

[Brooklinite]

While I have insufficient technical knowledge to be of much help here's what the previous owner of my '72 LT-1 did:

Stroked it to 383ci
Put in a hydraulic cam (edelbrock 7102)
increased compression to 11:1
swapped heads to 180cc AFR's
installed a Transistorized Ignition

That's all that I am aware of.

Dyno sheet says 475hp and 469 lb.ft.

Also, please note the differences in how horsepower was measured in 1970 vs. 1972 when you're comparing the two.

 

[fine69]

could you guys give me a little tutorial on what i need to buy and do to get this engine to near 400hp or so or in the 1970 LT1 hp

Read the other posts regarding how HP was recorded... you really seem to be hung up on hp... educate yourself. There are numerous posts on this subject here in the CAC.

 

[6880 Mike]

Leev: get your hands on some smallblock Chevrolet references. Dozens of these around and several How To Rebuild/Hot Rod Your Smallblock Chevrolet books.

Knowledge is power.

 

[MADLT1]

levv,what have to do is find a good engine builder near were you live,your engine wil mhave to come out of the car,dismantled and checked,depending on the size of your heads and wether or not the block needs to be bored will determine what size pistons yopu will buy,you cant just go and buy parts until you engine has been removed and pulled apart.it may have allready been bored so you need to find this out,its an lt1 so keep the cam a solid one,they make good roller cams now,dont let the compression get to high or the motor will ping,the octane in fuels today is not the same as what it was back in the 70s,good luck with it.

 

[Koop]

Take the LT1 out of the car and save it.

Install a ZZ383 and flog it.

 

[Tom Bryant]

Take the LT1 out of the car and save it.

Install a ZZ383 and flog it.

This is the best advice so far. These cars are really starting to move pricewise and that correct engine will make or break your car's value before too long. Plus going to 11:1 with those 70s combustion chambers will give you more detonation and premium fuel only problems than it will performance. Search the topic here and you will see that road test from the day show that the 71/72 LT1s were just as fast as the '70 and ran on regular gas.

You will be hard pressed to build your engine to the performance of a ZZ383 for the same price. If you do the only thing you will be using from your LT1 is the block. Buy new, get the warranty and save that original engine for the future.

Tom

 

[leev]

thanks for the help guys, i checked out summit racing and there qre quite the number of 383s with different compressions and such, some from blueprint? are they any good? could you recommend me a good engine for regular gas?

 

[JJS]

Search the topic here and you will see that road test from the day show that the 71/72 LT1s were just as fast as the '70 and ran on regular gas.

Tom

Tom is correct - the difference in speed between the 3 years is negligible according to the articles I've read from back then. I have a very good article (Road and Track?) somewhere regarding this topic. They took 3 LT-1's ('70-'72) and ran them each year. The results were virtually the same year after year.

I would take the advice already given - remove the stock engine and put in a crate motor if you're looking for 400+ hp.

 

[Koop]

This wiill put some beans in your burrito!

http://www.gmhorsepower.com/ZZ_383.html

This motor works great with pump gas and operates all of my Vacuum systems quite well. Some other set ups have to much cam then you start dicking with a vacuum boosting system, those suck. Drop this in and go with almost no pain. Someone here may know if you can get a single plane manifold under the LT1 hood! I had to run a dual plane to keep it all stock looking (because I like it that way) so I lost a couple of ponies.

You can get better pricing than this on this GM built and warrantied motor, but this is the good stuff. After market makers just don't have the R & D $ that GM does. Good luck if you go with Summit.

Post the VIN of the LT1 car so someone here can verify it's for real. I would be suspect of an LT1 car for $23,000 even in unrestored, well worn original condition.

Buy it.