well since there is a lot of questioning about actual LM1 350 horsepower id figure Id post this. In Hot-Rod U we work with LM1 crate motors. Run them stock and different stages of modification either in a car or on an engine dyno. Ive witnessed one dyno run so far as im not in that particilar class for another week yet. On this dyno run i witnessed they used a set of Holley aluminum cylinder heads, Edelbrock RPM air-gap intake, long tube headers, stock cam. Average peak power was 226hp and 303ft-lbs of torque. With the stock heads I would expect about 20 horse less. I will try to find out more on what the stock LM1's run. This was on and engine dyno BTW. This amount it considerably less than the 260hp seen advertised BUT they always say "up to" 260hp, which basically means you can get it to make anywhere from 1hp to 260hp.

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+ an 88 Caprice 9C1 Police Package
--Adam--
IM AOL: FieroGT5speed

Wow... and the 4.9 is considered to be a boat anchor? I don't have either so don't pay attention to me

What is different about the LM1 vs like an L98?

Thanks for the info. Does that mean that even with high flow heads, a good intake and the right cam, the max the LM1 will ever produce is around 260hp?

WTF is a "LM1"... IM assuming its a 350 cid V8? Is this TPI? TBI?

quote Originally posted by DOHC_SWAPPER: WTF is a "LM1"... IM assuming its a 350 cid V8? Is this TPI? TBI?

It's the basic GM crate 350 with regular iron heads (not Vortec).

quote Originally posted by Formula88: It's the basic GM crate 350 with regular iron heads (not Vortec).

Thank you.

quote Originally posted by Saxman: Thanks for the info. Does that mean that even with high flow heads, a good intake and the right cam, the max the LM1 will ever produce is around 260hp?

sounds like you need a vortec head swap

quote Originally posted by carbon: What is different about the LM1 vs like an L98?

Here are some "production specs" on the L98's of various years...
http://www.thirdgen.org/newdesign/tech/techdb.shtml

(my '89 Firebird Forumla 350 motor is rated for 240hp/345tq...)

I believe the primary differences are in the heads & intake systems... (of course, other than that - the blocks of nearly all small blocks are essentially the same ).

[This message has been edited by MinnGreenGT (edited 12-02-2005).]

quote Originally posted by MinnGreenGT: Here are some "production specs" on the L98's of various years... http://www.thirdgen.org/newdesign/tech/techdb.shtml (my '89 Firebird Forumla 350 motor is rated for 240hp/345tq...) I believe the primary differences are in the heads & intake systems... (of course, other than that - the blocks of nearly all small blocks are essentially the same ).

The L98 has a roller cam too.
The heads varied depending on where the engine came from. The L98's in the f-bodies had iron heads where as vettes from mid86 and up had aluminum versions of the same heads. They were all 58cc,1.94 intake valves, and 1.5-something exhuast valves. Not sure on the exact exhaust valve size as im not at home where i can look it up to make sure but i am sure about the intake valve size and cc of the heads.
The LM1 is one of the bottom of the barrel crate motors you can get from GM. It's meant to be a good deal pricewise.
IMHO, the L98 is a much better choice for motors. You would have to change a lot on the LM1 to get good numbers so, if you're going to do that anyway, why spend the money on a new engine when you could either buy a better crate motor or build up a used one?
As for aftermarket; they're both sbc's so there's more parts to make them faster than you can shake a stick at.

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My 79 Z28 came from the factory with the LM1. It was rated in the Camaro back then at a whopping 190 hp. Sure wasn't anything special. This would've been with the cast iron logs, single brick cat, iron intake, etc.

It's since been replaced with a L05, which is the 92-93 Caprice motor.

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85 GT 2.8/Auto (daily driver)
2 x 86SE 2.8/Auto (parts cars)
79Z28 / 94Z28 / 98Z28 / 93 Suburban
1 wife who thinks I'm nuts...

[This message has been edited by AKM (edited 12-02-2005).]

quote Originally posted by GTFiero1: well since there is a lot of questioning about actual LM1 350 horsepower id figure Id post this. In Hot-Rod U we work with LM1 crate motors. Run them stock and different stages of modification either in a car or on an engine dyno. Ive witnessed one dyno run so far as im not in that particilar class for another week yet. On this dyno run i witnessed they used a set of Holley aluminum cylinder heads, Edelbrock RPM air-gap intake, long tube headers, stock cam. Average peak power was 226hp and 303ft-lbs of torque. With the stock heads I would expect about 20 horse less. I will try to find out more on what the stock LM1's run. This was on and engine dyno BTW. This amount it considerably less than the 260hp seen advertised BUT they always say "up to" 260hp, which basically means you can get it to make anywhere from 1hp to 260hp.

Interesting, however, I wonder if this engine is one of those engines that's been dis-assembled & re-assembled 50 times by classrooms full of students that are learning how to to it.

Archie

You said stock cam right? Well there is a huge problem right there. No matter how good the heads flow if the cam isn't opening the valves up long enough ,high enough and at the right time, then it won't make impressive power.

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HARDCORE SBC CRONIE AND PROUD OF IT ! GOT TQ ?

The LM1 is better known as the target master 350 produced in mexico for gm from 1980 to 1994 it was GM,s econo 350 4bolt main replacment motor rated at 185 HP 300ftlbs torque and came complete less carb and dist. After 90 it came drilled for roller cams it is one of GM poorest produced replacement motors ever the cam only lasted 30.000 miles and where full of casting flanges not trimmed on the internals the would break of and cause engine failures .When new the need to be disassembled and cleaned up and cam replaced to make a reliable engine .

quote Originally posted by carbon: Wow... and the 4.9 is considered to be a boat anchor? I don't have either so don't pay attention to me What is different about the LM1 vs like an L98?

a stock 4.9 does ~165 hp and ~245 ft*lbs at the wheels so it's pretty proportional to an LM1 when you take displacement into account.

quote Originally posted by bubbajoexxx: The LM1 is better known as the target master 350 produced in mexico for gm from 1980 to 1994 it was GM,s econo 350 4bolt main replacment motor rated at 185 HP 300ftlbs torque and came complete less carb and dist. After 90 it came drilled for roller cams it is one of GM poorest produced replacement motors ever the cam only lasted 30.000 miles and where full of casting flanges not trimmed on the internals the would break of and cause engine failures .When new the need to be disassembled and cleaned up and cam replaced to make a reliable engine .

I don't think so, They don't have roller cams & they are 2 pc. rear seal blocks. All crate roller cam engines were on the one pc. seal engines.

I used to buy Targetmasters & the LM1 is not a TM as far as I can tell.

Archie

[This message has been edited by Archie (edited 12-02-2005).]

quote Originally posted by FIEROPHREK: You said stock cam right? Well there is a huge problem right there. No matter how good the heads flow if the cam isn't opening the valves up long enough ,high enough and at the right time, then it won't make impressive power.

yeah that pull was with a stock cam, ill have to see what others do with an upgraded cam. But that example was just ment to show the generally low output of the motor.

Archie is correct, they arent roller cam motors and use 2 piece rear main. the LM1 name tag has been around just for basic 350's. My 88 caprice's motor is coded LM1, which is a 2 bolt main roller cam motor made in michigan.

So, what do you guys think it will take to bring the LM1 over 300 hp? Since I already have one, I'm thinking it may be cheaper to upgrade.

What parts? What kind of $? Vortec has a new steel head for $700 and it looks like it flows as well as the aluminium heads.

The engine is coming out during the next month, so I might as well throw a few parts on it while it is out going into a new donor car...

Here is some more info on that engine. The price they have is a couple years old but the rest is accurate. http://www.lowcostengines.com/1067353.htm

I remember an article in Popular H.R., or Car Craft a couple of years ago where they took this engine added a cam & heads and made 330 HP on the Dyno.

Archie

quote Originally posted by Archie: Here is some more info on that engine. The price they have is a couple years old but the rest is accurate. http://www.lowcostengines.com/1067353.htm I remember an article in Popular H.R., or Car Craft a couple of years ago where they took this engine added a cam & heads and made 330 HP on the Dyno. Archie

Cam and heads are pretty major upgrades.

Just order a short block and add some Edelbrock heads, intake, cam and make 350hp.

[This message has been edited by crzyone (edited 12-03-2005).]

quote Originally posted by bubbajoexxx: The LM1 is better known as the target master 350 produced in mexico for gm from 1980 to 1994 it was GM,s econo 350 4bolt main replacment motor rated at 185 HP 300ftlbs torque and came complete less carb and dist. After 90 it came drilled for roller cams it is one of GM poorest produced replacement motors ever the cam only lasted 30.000 miles and where full of casting flanges not trimmed on the internals the would break of and cause engine failures .When new the need to be disassembled and cleaned up and cam replaced to make a reliable engine .

I've never heard of the 350's having cam problems. Are you sure you don't mean the 305's? They would wear out cams fast and had lots of quality issues back in the 80's. This is why in 87 they started using the 350's in the F-body cars as the top engine.

[This message has been edited by Oreif (edited 12-03-2005).]

quote Originally posted by Oreif: I've never heard of the 350's having cam problems. Are you sure you don't mean the 305's? They would wear out cams fast and had lots of quality issues back in the 80's. This is why in 87 they started using the 350's in the F-body cars as the top engine.

there are 3 differant target master builds from GM

the first ones where mad at the Tonawonda plant in the US and in the Ohsawa plant in Canada from 75 to 80 and where 165 HP
the second series where made in mexico when the Tonawonda plant was closed and the foundry sent there they are the 185 HP units
with the bad cams and poorly cleaned up blocks with the 2 pice seal made from 80 to 87
and the third are the one piece seal models made as base replacement motors for 87 to 94 GM cars to 92 and trucks to 94and are target masters they are the standard replacement cheepie GM sells .These are still 185 HP engine and of typical mexician quality just look at the GM cars comming out of mexico they rot in the firewall area like crazy if you lift the insulation you see that the whole area has no paint on it
have seen many cavalies, sundirds ,calaisand sunfires with the steering rack hanging where the firewall rotted right though in 3 years.Also paint falling of the body in less than 3years yet US and Canadian cars hold up 10n times better

quote Originally posted by Archie: Here is some more info on that engine. The price they have is a couple years old but the rest is accurate. http://www.lowcostengines.com/1067353.htm I remember an article in Popular H.R., or Car Craft a couple of years ago where they took this engine added a cam & heads and made 330 HP on the Dyno. Archie

Yeah, I have that hot rod issue buried somewhere. They give you part numbers and everything. That article is where I first learned about the ideal rod length:stroke ratio and the setup they used gave it a 1.75:1 ratio. It used a 2 bolt main. It was about doing it cost effectively as well.

[This message has been edited by lou_dias (edited 12-03-2005).]

quote Originally posted by crzyone: Just order a short block and add some Edelbrock heads, intake, cam and make 350hp.

That's a good option too, however, I think he said he wanted to upgrade the existing engine.

Archie

quote Originally posted by bubbajoexxx: These are still 185 HP engine and of typical mexician quality just look at the GM cars comming out of mexico they rot in the firewall area like crazy if you lift the insulation you see that the whole area has no paint on it have seen many cavalies, sundirds ,calaisand sunfires with the steering rack hanging where the firewall rotted right though in 3 years.Also paint falling of the body in less than 3years yet US and Canadian cars hold up 10n times better

Hmmmm....the ZZ4 crate engine is also manufactured in Mexico. Anyone having quality issues with these?

quote Originally posted by Oreif: I've never heard of the 350's having cam problems. Are you sure you don't mean the 305's? They would wear out cams fast and had lots of quality issues back in the 80's. This is why in 87 they started using the 350's in the F-body cars as the top engine.

That's not why the 350 was used as the top engine. People wanted the bigger engine pure and simple. The vette had it and f-body people wanted it too. It's only fair considering that the first car the 350 was ever in was a Camaro. History helps sometimes. People/customers wanted the bigger engine and it had heritage on it's side so they won eventually.
Never heard of quality problems with cams in 305's. The 305's did have quality problems on their heads though. They were prone to cracking.

quote Originally posted by lou_dias: Yeah, I have that hot rod issue buried somewhere. They give you part numbers and everything. That article is where I first learned about the ideal rod length:stroke ratio and the setup they used gave it a 1.75:1 ratio. It used a 2 bolt main. It was about doing it cost effectively as well.

If you find that issue, I'd love to see a scan of it! These steel Vortec heads ($500 a pair) have me ready to buy...

quote Originally posted by Dave Gunsul: Never heard of quality problems with cams in 305's. The 305's did have quality problems on their heads though. They were prone to cracking.

I know quite a few who had 305's that required a new cam. Some in F-body cars and a few others. I changed out one in a friends Caprice and help others back then as well. Come to think of it, It may have been the carb'd version of the 305's as I can't remember ever changing one on a TPI car. So it could have been limited to a specific cam.

I also remember lots of people complaining about the 305's and then they started installing 350's. Then again the mid to late 80's was the big power wars between F-bodies and Mustangs. Every year the engines gained a little more horsepower as each company tried to have the more powerful car.

I think the 350 was put in the F-body to compete against the Mustang. Even with TPI, the 305 was still slower than the Mustang 5.0. The 350 was the first time the third-gen was faster.

Wasent the LM1 350 plopped into f-bods from 79-81? z28s in particular.. rated between 175hp -190.

quote Originally posted by GTFiero1: you should find a stock LT1 f-body cam to put in that L05, usual gains of about 20-25 horse on a stock L05 and people practically give the stock cams away

Too late. Already put a CompCams 302 in there (210/220 duration, .480/.480 lift) with matching springs. Intake's an Edelbrock Performer, Holley TBI unit, Hooker headers and Flowmaster American Thunder dual exhaust. All I need is a Nascar hat, a mullet, and a Budweiser, and I'm golden.

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85 GT 2.8/Auto (daily driver)
2 x 86SE 2.8/Auto (parts cars)
79Z28 / 94Z28 / 98Z28 / 93 Suburban
1 wife who thinks I'm nuts...

Now I'm not sure I want to put the LM1 into the new donor car...

Anyone need a slightly used LM1?

quote Originally posted by Saxman: Now I'm not sure I want to put the LM1 into the new donor car... Anyone need a slightly used LM1?

well i'd say a nice replacement would be in order then.. perhaps something from a mid 90's chevy? like thhe one from a 95 z28 camaro rated at 275hp.. can pick one of those up with harness and 70K on the clock for 1400$

quote Originally posted by Kohburn: well i'd say a nice replacement would be in order then.. perhaps something from a mid 90's chevy? like thhe one from a 95 z28 camaro rated at 275hp.. can pick one of those up with harness and 70K on the clock for 1400$

for that kinda money you should be able to pick up an ls1 from a 98 or newer camaro with all accessories and wiring harness/ecm.

matthew

quote Originally posted by m0sh_man: for that kinda money you should be able to pick up an ls1 from a 98 or newer camaro with all accessories and wiring harness/ecm. matthew

the listings place one of those at abou 1900, 1400 will get you a reuildable core

quote Originally posted by m0sh_man: for that kinda money you should be able to pick up an ls1 from a 98 or newer camaro with all accessories and wiring harness/ecm. matthew

Before you go buying an LS1, you need to know that NONE of the current SBC conversion kit parts that you have will work with the LS1. You need a whole new kit for the LSx engines.

Archie

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Well, Merry Christmas to me! (Thanks for the info, Archie )

Oh well, I should be able to pull 275hp out of the LM1 by adding Vortek heads (new steel Vortek's are $700 now) and a cam, right?

[This message has been edited by Saxman (edited 12-31-2005).]

How many HP do you guys think Vortek heads and a good cam will add?

quote Originally posted by Saxman: How many HP do you guys think Vortek heads and a good cam will add?

Chevy High Performance - Small Block Chevy Engine Buildups (ISBN:1-55788-400-5).
Page 75 gives you the dyno numbers for a 350, 9.75 CR, GM HOT Cam, Vortec Heads, Lt4 springs, Dual & Single plane GM performance parts Intakes, 750 barry grant carb. End result 412 HP for the dual plane intake and 422 HP at 5700 RPM for the single plane. This page has every part number (mostly GM part #'s) for this build using a stock 89 caprice block, crank and rods and hypereutetic pistons. This build was done with stock ports on the heads and intake (no porting or polishing) and should be rather easy to duplicate if you wish to do so.

Vortec heads are great and are one of the highest flowing mass produced stock SBC heads available. However, don't plan on just bolting them on. They should be convertered to screw in rocker studs and machined for lift greater than "about" .480 (I can't remember the exact #) as well as machined for better valve springs. You can buy them with all this work already done for about $700.

When you build an inexpensive engine with HP in mind, spend about 1/2 of your $$ on the heads and cam.

[This message has been edited by fieroguru (edited 12-31-2005).]

Thanks for the HP info you guys. I got sidetracked and did not check this thread for a while. GTFiero1, have you had a chance to mess with the LM1 any since you started this thread?