LS6 and LS5 Engines

[GWHITE75]

Lanelle,

I agree with Tom. The truck block is an excellent block to work with, especially if you want to make your motor bigger. One reason your belts might not have fit is that the truck block has a taller deck height than the passenger car block. The deck is the surface where the head bolts onto the block and it is just under 1/2" higher.

The taller deck height raises everything above the block deck almost 1/2", which means that anything having to bolt onto the heads, such as the alternator or A/C compressor brackets will be a little higher and would require longer belts.

I have a truck block I pulled out of my Vette last year. Because it is a truck block, I was able to run a 1/4" longer crank (stroker)and bore it out .060. This gave me a 496 CI motor and it had some good HP and torque. The truck blocks were made for heavy duty operation, so it should not depress you. These blocks can be bored to .100, if absolutely needed, and still work good.

Take care,

Gary

 

[groovyjay]

LS5 = iron heads with oval ports
LS6 = (Corvette option) Aluminum heads with square ports

LS7 was also available but no such car was ever build, but the option HP was rated at 460hp.

 

[BigBrakeFuelie]

Great White your 75 is a trip.It looks like an 80-82.Is that a body kit customized?

 

[C3Vette Lady]

More on the 454 LS6 saga...

Ok, I now know the block was produced in Dec. of 78 for a truck. So most likely it went into a '79 truck. The heads are rectangular port and have "HI-PERF" stamped in them, but I put a magnet to them and it didn't stick, so they are not aluminum.

Getting info from previous owners is impossible. Basically what I will have to do is take it apart piece by piece and see what is there and change what I want to change I guess.

Thinking about getting it dynoed the end of the month ($day) just to see where I am starting at. Yes, the guy I bought it from said it was "hi end, hi performance 454" and my mechanic who was there said he said it was an LS6 engine, but not the original one obviously.

Anyway, thanks for your help, and I will keep you posted as to what I find out. Or, if you have any ideas or info, please share! Can't wait until Monday when my mechanics return to work to tell them why the belts didn't fit! At least now, when I need parts, I know what type of engine to get them for.

Wondering if I should change my custom license plate from VETRESS to TRUCKESS? hahahahahha! Lanelle :eyerole

 

[vettepilot]

Re: More on the 454 LS6 saga...

Ok, I now know the block was produced in Dec. of 78 for a truck. So most likely it went into a '79 truck. The heads are rectangular port and have "HI-PERF" stamped in them, but I put a magnet to them and it didn't stick, so they are not aluminum.

Getting info from previous owners is impossible. Basically what I will have to do is take it apart piece by piece and see what is there and change what I want to change I guess.

Thinking about getting it dynoed the end of the month ($day) just to see where I am starting at. Yes, the guy I bought it from said it was "hi end, hi performance 454" and my mechanic who was there said he said it was an LS6 engine, but not the original one obviously.

Anyway, thanks for your help, and I will keep you posted as to what I find out. Or, if you have any ideas or info, please share! Can't wait until Monday when my mechanics return to work to tell them why the belts didn't fit! At least now, when I need parts, I know what type of engine to get them for.

Wondering if I should change my custom license plate from VETRESS to TRUCKESS? hahahahahha! Lanelle :eyerole

C3Vette Lady,
I had to pull your last reply into this as a quote so I could attempt reading and answering... LOL
In your first sentance, you said you found the "HI-PERF" stamping, but when you put a magnet to them it didn't stick, so they are not aluminum.
The good news is, a magnet shouldn't stick to aluminum, it is non-ferrous, therefore no stickum... in that case you have aluminum heads, so far so good huh?

Like everybody else has already said, the LS6 was at it's best in 1971 as far as the Corvette application is concerned. It was a solid lifter, 9.0:1 CR, 425 HP@5600, 475 lbs TQ@ 4000 1x4bbl carb, priced at $1221.00, available with either the 4spd or TurboHydra-Matic.

The exact HP/TQ figures for your particular engine will probably differ greatly from the factory Corvette figures because it didn't start life as a Corvette application. At least as far as we can determine at this point.
I would suggest doing a dyno run to see what you have for HP/TQ. If it's good numbers, and your satisfied with the performance it's all good.

vettepilot

 

[vettepilot]

I was just reading through this entire thread again, looking for something that I read that caught my eye earlier... I found it in one of your posts that said the guy you bought it from said it was a "1970 LS6/ high performance top end" engine. Sounds like you got the top end of the LS6 alright, but not the bottom end.
Just thought I would toss that out there because it sounded like a play on words when I read it the first time around, and even more so now.
vettepilot

 

[C3Vette Lady]

Corrections.....ugh.....

2 things to correct here. Got in touch with the guy I bought this car from and he corrected me and said it was an engine from a '71, not a '70. However, after checking the numbers on the block, it was traced to being cast on December 12. 1978 and for a truck, not a corvette.

When it was in the shop, I asked my mechanics to see if the heads were aluminum or not and they said yes, they put a magnet by the heads and they were aluminum. However, I decided to double check that. The first tool I was using made it seem like it didn't stick, so I changed and found something else. It stuck. I guess my mechanics used something like I did at first and it seemed like it didn't stick. So, final results prove that the heads are NOT aluminum. There are "hi perf" heads that aren't aluminum. I have found several on Ebay, for example.[COLOR]

So, looks like the guy I bought the car from was given inaccurate info.

Frustrated,
Lanelle

 

[Bullitt]

I think all gearheads and new "old" car owners go through this maybe it's the rare engine I've heard about phase. Many of us find out we were just dreaming (I dreamed of the 430 Can-Am engine) and get a bit disappointed at what we really own. It's only until we actually take apart the engine can we surely know what lies in the beast or semi-beast, as the case may be. Then, either we can find elation (as one CAC member did when he happened on a 4-bolt 454) or begin our plans of building a monster. Whatever happens, try not to let stuff like this get you down. Just remember that some poor slob out there is driving a Neon and hates every minute of it, especially when he sees a Corvette.

--Bullitt

 

[C3Vette Lady]

LMAO!

Ya Bullitt! That is a good thought to remember.....I could be driving a Neon! Actually I drove a uh, Rambler, in my days once upon a time... Thanks for making me laugh! :L