what is the diff between an LS1 and LT1
Registered User
Joined: Aug 2003
Posts: 915
From: Tucson, AZ
Re: what is the diff between an LS1 and LT1
LS1 has an all aluminum block, LT1 has an iron block (iron heads on caprice/roadmaster versions, camaro/corvette got alum. heads on LT1).
LS-1 has a completely different ignition setup - coil per cylinder. The LT1 has a horrible ignition setup using what is called the optispark - it's a distribibutor basically that is mounted ont he front of the engine and driven off the camshaft.
The engines have radically differently head designs...
The engines have radically different intakes. The LS1 has the plastic intake where as the LS1 has a cast iron intake.
Those are the big differences.
LS-1 has a completely different ignition setup - coil per cylinder. The LT1 has a horrible ignition setup using what is called the optispark - it's a distribibutor basically that is mounted ont he front of the engine and driven off the camshaft.
The engines have radically differently head designs...
The engines have radically different intakes. The LS1 has the plastic intake where as the LS1 has a cast iron intake.
Those are the big differences.
Registered User
Joined: May 2004
Posts: 343
From: Albany, Ohio
Re: what is the diff between an LS1 and LT1
Well....I'll do my best. The LS1 is an all-new design, and has nothing or very little to do with the original Chevy 350. The LS1 is all-aluminum, and has coil-on-plug ignition system, composite intake manifold, and is actually a 346 cu engine, so it is just a hair smaller than the LT1.
The LT1 is an improved on design of the early chevy small block which dated back to 1955 I believe. Unlike the LS1, it has a cast iron block, heads are aluminum. The LT1 is actaully a more finicky design than the LS1. The LT1 has unique features such as reverse flow cooling, Optispark distributor, and the water pump is driven off the camshaft. The Optispark is a step that GM took which is between the regular distributor setup like in TPI IROC-Z cars, and the new coil-on-plug setup like the LS1.
That's about the best I can do. I am sure there are more differences, but I'll let someone else take over from here.
Oh...one other difference....The LS1 has more horsepower in stock form. For instance a 1997 LT1 Z28 has 285 HP, and a 1998 Z28 has 305 HP. (320 with SS package)
The LT1 is an improved on design of the early chevy small block which dated back to 1955 I believe. Unlike the LS1, it has a cast iron block, heads are aluminum. The LT1 is actaully a more finicky design than the LS1. The LT1 has unique features such as reverse flow cooling, Optispark distributor, and the water pump is driven off the camshaft. The Optispark is a step that GM took which is between the regular distributor setup like in TPI IROC-Z cars, and the new coil-on-plug setup like the LS1.
That's about the best I can do. I am sure there are more differences, but I'll let someone else take over from here.
Oh...one other difference....The LS1 has more horsepower in stock form. For instance a 1997 LT1 Z28 has 285 HP, and a 1998 Z28 has 305 HP. (320 with SS package)
Registered User
Joined: May 2004
Posts: 343
From: Albany, Ohio
Re: what is the diff between an LS1 and LT1
I disagree that the Optispark is horrible. I get so sick of hearing that. I have put 45,000 on my LT1 with no trouble. If not for the Optispark, the LT1 would have never had the stock HP it did. It was one of the many details that made the LT1 such a stronger performer than the L98 it replaced. It was the Opti, along with the reverse flow cooling which allowed for a higher compression, and a better flowing intake/exhaust.
Registered User
Joined: May 2004
Posts: 343
From: Albany, Ohio
Re: what is the diff between an LS1 and LT1
Originally Posted by indieaz
The optispark when functioning is fine, it's the frequency of breakage that is the problem.
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Joined: Dec 1969
Posts: 3,499
From: PORTLAND, OR, MULTNOMAH
Re: what is the diff between an LS1 and LT1
LS1 heads are made like heads should be made, i.e, the damn intakes and exhausts actually line up with the cylinders, therefore better flo out of the box. When compared to the LT1 heads you wonder what the hell the engineers were thinking. So my guess is that accounts for most of the HP/TQ differences out of the box.
BTW Since the RWHP of a typical 1st year LS1 F-Body was between 280-305 the power at the crank would be closer to 330-350: The factory quotes were probably low so as to make the vette look better.
To support my opinon on the head differences, one need only take an Lt1 head and give it a good porting and get the stock numbers of an LS1. JMHO
BTW Since the RWHP of a typical 1st year LS1 F-Body was between 280-305 the power at the crank would be closer to 330-350: The factory quotes were probably low so as to make the vette look better.
To support my opinon on the head differences, one need only take an Lt1 head and give it a good porting and get the stock numbers of an LS1. JMHO
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Joined: Apr 2003
Posts: 1,179
From: Ballwin, MO
Re: what is the diff between an LS1 and LT1
The heads and cam base circle are the biggest change for power production. The heads are a 15* setup instead of 23* which gives you a straighter shot intoand out of the ports. The base circle allows a larger selection of lobes for aftermarket cams. The firing order is improved along with long connecting rods.
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Joined: May 2002
Posts: 622
From: Nashville, TN
Re: what is the diff between an LS1 and LT1
http://www.idavette.net/hib/ls1c.html
Oh, and the LT1 sounds better IMO with the right exhaust. It's a little deeper than LS1's, but both sound good.
Jason
Oh, and the LT1 sounds better IMO with the right exhaust. It's a little deeper than LS1's, but both sound good.
Jason