Barry's70LT1

Just to add to the confusion, and I won't estimate a Horsepower.

I've owned my '70 LT-1 since new and did some racing "back in the day". It's completely stock with the exception of headers added.

On street tires, (Goodyear Polyglas - very poor traction), my 1/4 mi times were consistent 13.1x @ 107-109 mph. Best time 13.02 @ 110 mph.

The NHRA "Factor Finder" manual for classifying Super Stock and Stock classes (Page 10) rates the '70 LT-1 @ 400 HP and the 70' 454 @ 415 HP

In comparing the 454 with the LT-1 in a 1/4, there would not be much difference. The LT-1 might have an advantage due to less weight and higher revs.

bondoboy

Didn't the vette use the rams horn manifolds and the Camaro used the newer style manifolds?

69autoXr

LT-1/ZR-1 did have the L88 15lb nodular iron flywheel, so technically, the two did have something common between them.

7t9l82

who does this?

BKbroiler

Since back in the day was probably 40 years ago, and you're in Canada, are you sure you're not confusing miles per hour with kilometers per hour?

stuartc53

I disagree. I feel it was underated at 370 hp. Consider the '64 & '65 327 365 hp. It used used a Holley 600 cfm, not a 780. It was 23 cubic inches smaller and not built as strong as the LT-1. Based on that, I believe the '70 LT-1 is about 430 hp. Comments are welcome

cv67

disagree it takes quite a bit to make 430hp with stock iron heads and a flat tappet, manifolds etc. they dont pull like say 350rwhp for sure. id bet 350chp tops

LT-1 kid

the 70-72 LT-1s are a nice little motor very stout, hp ratings may of been a little heavy. they need at least a 3:70 gear, best is 4:11 .LT-1/ZR-1 as mentioned has the l88 light flywheel 10.5", for faster revs, but BBs do produce more torqe and ultimitly HP. put the same gear in a BB and no contest, had and have both.

stuartc53

Thanks for responding. Has anyone out there put their LT1 on a dyno to measure the HP? I would like to know the results. No one has addressed the '65 327 365 hp engine, either. Was the 365 a fluke too? I can not see it putting out more hp than the LT1.

LT-1 kid

had a 64 365 with a 4:11 a few years ago, I frame off restored it, original motor and componets, and the LT-1s were faster and stronger IMO.

stuartc53

so were do they people get off saying the LT1 is only 350 HP?

Barry's70LT1

No confusion here, still have the time cards.........

Also, the strip was right at sea level, that helps a little.

69ttop502

Because the 365 was only 340 or so. I really don't think the LT-1's were at all overated. I have just completed a rebuild of my 62 340 horse engine. All OEM except I used the LT-1 cam. It still has some dyno flogging to do but even with the upgraded cam, it only made 330 hp. Comparing trap speeds of old road test show that the 340's, 365's and LT-1's ran very similar trap speeds. Although the weights of the C1's C2's and C3's that these engines ran in varied somewhat, the engines were very similar. Remember that the LT-1 cam is smaller than the 30 30 in the 365's. Apparently the intake was better on the LT-1. All in all there really wasn't enough difference to say any were far off their advertised hp ratings.

Bill

stuartc53

Apparently then all the HP ratings were inflated. So I would guess the 300 HP 350 engine was closer to 270. Obviously its easier to list or talk about high HP than it is to make it. Thanks for sharing

LT-1 kid

you are correct, its hard to build HP, but also the 350 has more stroke than the 327, = more torqe than = hp. but all solid lift motors need gears , down low there alittle doogy, thats why the L46 is such a good all around motor.

stuartc53

[QUOTE=LT-1 kid;1584799131]you are correct, its hard to build HP, but also the 350 has more stroke than the 327, = more torqe than = hp. but all solid lift motors need gears , down low there alittle doogy, thats why the L46 is such a good all around motor.[/QUOTE

The L46 is one motor I have not owned in a Vette. I can see where it makes a lot sense. No valves to adjust and quiet hydraulic lifters along with good torque and HP. The 352/300 Hp motor is a fine performer as well, with decent gas mileage to boot. Thanks for sharing

7t9l82

LT-1 kid

wow, 2 dead horses.

scottyp99

I think this is as close as we'll ever get to settling this debate:

http://www.superchevy.com/technical/...g/viewall.html

http://www.superchevy.com/technical/...g/viewall.html

It may be whipping a dead horse, but it's still an interesting read.

Scott

hammy5454

Hi all,
Well, this comes from my personal experience as well as what I can recall reading in magazines in the seventies.

First, we all know that hp ratings were a joke back in the day. They were either under rated for insurance reasons (428 CJ = only 335 hp?) Really? On the other end of the spectrum, we have the mighty mouse
L79 327 rated at 375hp and the LT-1 at 370 hp (doubtful on both counts).

Here's what I have. I purchased a 1971 LT-1 Corvette in 1985. It was in need of a lot of TLC but, everything was there and it was a perfect candidate for restoration. I took it to our local track early on. It was an oil burner and it smoked like a train but, I wanted to get a baseline. My best ET of the day was a disappointing 15.12 @ 91 mph!

Next off to my local chassis dyno where it recorded an astounding 219 hp! Ha!

Well, I seem to recall some road tested ETs from Car Life, Road and Track and Hot Rod magazines. I recall a 14.09, a 14.36 and a 14.45 as some of their ETs, all at around 101 mph. So, I knew the car had potential.

After I had the car in the beginning stages of restoration, I began to participate in the Pure Stock Drags sponsored by MuscleCar Review Magazine in Mid Michigan. (Special thanks to Bob Boden and Dan Jensen BTW, for getting me started).

Anyway, to complete an already long story (sorry) ... after a few years and with the car 99% restored, I recorded a best ET at their event of 13.82 @ 103 mph. This was on a stock (.030 over) rebuild with smog pump intact and on original style F70/15 Firestone Wide Oval bias ply tires. The only upgrades were that I had the heads massaged with a 3 angle valve job and a bit of polishing AND the addition of a 2 1/2" SS exhaust. Otherwise, this car was bone stock. (Stock exhaust manifolds, 3.70 rear end, etc.)

Now, back to the chassis dyno where the car recorded 292 hp at the rear wheels.

If you recall, back in 1971, they started rating hp as GROSS (at the flywheel with no power accesories attached, etc., etc.) and NET (which I believe was at the rear wheels as on a chassis dyno.)
The LT-1 for '71 was factory rated at 330 hp GROSS and 275 hp NET.

So, in conclusion my slightly higher hp rating (due to minor modification) and my slightly quicker ET and higher mph makes complete sense. Also, the factory NET rating of 275 hp was probably pretty accurate.

I DO really miss that car however, my 2014 Z51 Vert which I have on order will hopefully, ease that heartache!

Thanks for listening! Comments?