mike229

I did a search on this topic and found some info but nothing definitive...

If I end up with a #s matching all original '70 LT1 (11:1 comp) or LS5 454BB (10.25:1 comp), will there be ANY issues using pump gas? (93 Octane)

If there are - is there any benefit to sticking with a 1971 LT1 or LS5 with lower compression? (besides that they are a little cheaper to buy :-)

I understand that compression isnt the only issue, but it seems like its the primary one anyway...

Thanks in advance!!
Mike


[Modified by mike229, 6:28 PM 2/29/2004]


[Modified by mike229, 6:28 PM 2/29/2004]

mike229

ttt

PRNDL

10.25:1 should be fine on premium gas. My 68 L36 is 10.25:1 and I have no problem with Amoco premium. I passed a 70 LT1 coming out of the racetrack once. The owner was not racing his vette - he only stopped by to get some race gas. Could be an issue with a 70 LT1. MJ

Gordonm

You can make a 9:1 motor ping on premium if the cam has a short enough duration. It all depends on cylinder pressure. A long duration cam with high compression can run on pump premium. Normally a 10:1 motor is about it for premium.

IRON 82

Your LT1 and LS5 are for 93 Octane and higher. Anything lower will damage your engine. Make sure you also use a synthetic oil. This will help maintain your engine. :yesnod:

IRON 82

Bullshark

Mike, Finally a question right up my alley, I have both a 70 LT-1 and a 70 454 LS-5. The LT-1 should not be run on today's 93 octane pump gas, the stock heads do not have hardened valve seats and need lead additive to survive for any lenth of time. I agree, with 11:1 compression you should not risk it. (even though I have babyed it on rare occasion with the timing slightly retarded.) The LS5 at 10.25 is also a risk. The head desigh back then didn't burn quit as efficient as it does with today's technology. That's why my stock engine is rebuilt and sitting in storage while I play around with the RamJet 502" It has 9.6:1 compression and goes like a bat out of H__l

Bullshark :auto:


[Modified by Bullshark, 10:04 PM 2/29/2004]

72ls5fla

Hi ..

There is a company thta makes real TEL lead addititve.
called Lead Supreme 130.

If you mix 1oz per gallon to 93 octane gas you end up with 95-96 octane leaded fuel, actually low lead. additive gets .5 gram of lead.
32oz costs near 10.0, so it adds about .20-.28 cents per gallon to pump gas.

I been using it for 2.5 years. works great !!

They come in a 32oz quart botle - great for traveling.

Maybe this will help you some.

Bill

LT1driver

my 70 LT-1 runs fine on premium gas with stock advance setting. :D