Dart LT1 block a "no go"

[unstable bob gable]

For a few quick minutes Dart was considering coming out w/ an LT1 spec block, which woulda allowed an LT1 style engine in the 427+ cube range. But they backed out. I was looking into this heavily, as I really want more than 396 cubes outa my Dominion headed LT1 build. I'm gonna talk to my engine builder this weekend and crunch some numbers. I may consider talking to Donovan, as they have built some of their blocks to LT1 specs. Why go into battle with under 400 cubes and a factory block, when there are much more cubes to be had and a block with a superior design to be used? It ain't like my project is gonna be done tomorrow anyways...lol

[LTb1ow]

Are the dominion heads SBC heads converted to LT1?

[unstable bob gable]

Originally Posted by LTs1ow

Are the dominion heads SBC heads converted to LT1?

If and when the guy [Russ Arao] builds the heads for you he will make them for either the conventional small block or LT1. Mine were build as LT1 spec models from the git go.

[LTb1ow]

Ah, well in that case, you could be the very first person to convert LT1 heads to work on a SBC!

[unstable bob gable]

Originally Posted by LTs1ow

Ah, well in that case, you could be the very first person to convert LT1 heads to work on a SBC!

Actually, back in the LT1s era I remember reading a few articles on guys who converted LT1 heads to work on a conventional SBC. LT1 heads were decent heads for their time+had a good manifold. So, there were prolly worse ways to go...

And my engine guy doesn't want to convert the heads to regular SBC style...reverse cooling is part of his plan for the build. Soooo, I'd have to come up with a block with LTx style cooling.

[Slow Z]

Originally Posted by LTs1ow

Ah, well in that case, you could be the very first person to convert LT1 heads to work on a SBC!

Been done many times. I've even seen factory LT1 intakes that have been modified to accept a conventional distributor. Personally I think it's kind of a waste of time but neat nonetheless.

Anyway, unstable bob gable, I'm assuming you're building a "race" motor? Why waste so much money on an LT1 and potentially paying $3000+ just for a block? The cost just doesn't seem to justify the possible (and probably small) gains to me. It just makes a lot more sense to go with a conventional SBC money and power wise.... I'm all for people doing "different" things but I'm also all for people doing logical things and I just don't see the logic.

[Mike]

because he isnt building a race motor

[BonzoHansen]

Originally Posted by cbrrmike

because he isnt building a race motor

He keeps talking about maxton & doing 200. So maybe he is?

[sweetbmxrider]

Originally Posted by Slow Z

Been done many times. I've even seen factory LT1 intakes that have been modified to accept a conventional distributor. Personally I think it's kind of a waste of time but neat nonetheless.

yeah thats somewhat common. also converting the heads or intake to mate a carb single/double plane. pretty sweet.

Get the lt1 block half filled and do a 396. There's guys going mid 8s with it. Btw slowZ how is staying lt1 restricting him? He can have abc heads converted for $400 and it's basically a sbc with better cooling. He can go with a crank trigger setup if he pleases but the opti doesn't restrict anything, the PCM does. He can go xfi and spin it to 8k if he wants

[Slow Z]

Originally Posted by cbrrmike

because he isnt building a race motor

Talking about needing an aftermarket block with 400+ cubes and "going into battle" sure sounds like a race motor?

Originally Posted by JerzLT1

Get the lt1 block half filled and do a 396. There's guys going mid 8s with it. Btw slowZ how is staying lt1 restricting him? He can have abc heads converted for $400 and it's basically a sbc with better cooling. He can go with a crank trigger setup if he pleases but the opti doesn't restrict anything, the PCM does. He can go xfi and spin it to 8k if he wants

It's restricting him because they don't make the block he wants (needs?)... That's a big reason go to "hey you know what, screw this!" I just dont think the "better cooling" of an LT1 is really all that superior to an aftermarket block conventional SBC when you factor in the price to do it. Also filling the block would definitely decrease that "superior cooling" on a major scale.

[SteveR]

Originally Posted by Slow Z

Also filling the block would definitely decrease that "superior cooling" on a major scale.

And most likely make it a track only motor.

so you think half filling the block would cost more then an aftermarket SBC block? btw theres a half filled turbo LT1 that goes 8.55 and drives it on the street without a problem

[Pampered-Z]

I too was looking at the Dart block, my concern was that LT1 heads, or aftermarket LT1 heads really don't have the flow to feed a serious 427CI. To make a 427CI LT1 you would need to go the route of someone like N20Dave and look at SB2 heads. By the time you get the heads and aftermarket LT1 block it would be a whole lot cheaper to just go a different route. If you look at those single digit LT1s they too suffer some some of the problems inherent with stockblocks. Cap walk, block flex. an ultra strong block such as dart would built would allow you to push much further. If I ever decide to loose the LT1 it would be replaced with a big block.

Of course, UB isn't going to have that problem, he already has heads with major flow potential and a stud girdle. Unlike the rest of us, Bob has the uncommon parts that will allow him to push a stock block where the rest of us can't.

[Tru2Chevy]

Originally Posted by Slow Z

Anyway, unstable bob gable, I'm assuming you're building a "race" motor? Why waste so much money on an LT1 and potentially paying $3000+ just for a block? The cost just doesn't seem to justify the possible (and probably small) gains to me. It just makes a lot more sense to go with a conventional SBC money and power wise.... I'm all for people doing "different" things but I'm also all for people doing logical things and I just don't see the logic.

He's building the motor around a set of these LT1 heads:



- Justin

[unstable bob gable]

I'll try and fill in the blanks for those that aren't familiar with my "project."

I own basically all the parts to build a 396 [4.030 X 3.875] LT1, including a block that has been reworked to within an inch of it's life. I'm just looking for the "ultimate" set up to put under those 32V heads. There is no substitute for cubic inches, and my LT1 block is at the end of it's C I limits now. A bigger engine not only has more power potential for me, but won't have to work as hard to make that power. Plus there are the advantages of what an aftermarket block can bring to the table as far as strength, lighter weight, improved cooling/oiling systems, etc. I am building this car to be a high end, no frills Trans Am type car that will be streetable. I want it to run on pump gas, but want to shoot for 200+ MPH at Maxton.

[1QWIKBIRD]

Have you done any homework or talked with other LSR guys to know what kind of power you need to push the AMX through the air at 200mph or what the frontal area of the car is and how slippery (aerodynamically speaking) it is? Curious?

I am thinking along the lines that if the car's aero is sorted out, the power required should be less, which could make this whole thing easier to pull off and safer for you (assuming your doing the driving).

Chris

[unstable bob gable]

Originally Posted by 1QWIKBIRD

Have you done any homework or talked with other LSR guys to know what kind of power you need to push the AMX through the air at 200mph or what the frontal area of the car is and how slippery (aerodynamically speaking) it is? Curious?

I am thinking along the lines that if the car's aero is sorted out, the power required should be less, which could make this whole thing easier to pull off and safer for you (assuming your doing the driving).

Chris

I know of a guy who pushed a 70 Javelin to over 200 MPH in the Silver State road race, but he's a prick who won't give up any "secrets." A few AMC guys have commented that he prolly had over 600 HP, and his body style Javelin is less aero than mine, so I think I'm working with a better body design and engine package. I've also done some homework on 2nd gen F-bods who have gone 200+ MPH, as they have a similar profile as the Javvy. But power overcomes all...as the Big Red '69 Camaro had the aero of a brick, but still went well over 200 MPH.

[unstable bob gable]

Welp, I'm out da door to go visit my engine and drop a bag o' cash on da builder!

[1QWIKBIRD]

Originally Posted by unstable bob gable

I know of a guy who pushed a 70 Javelin to over 200 MPH in the Silver State road race, but he's a prick who won't give up any "secrets." A few AMC guys have commented that he prolly had over 600 HP, and his body style Javelin is less aero than mine, so I think I'm working with a better body design and engine package. I've also done some homework on 2nd gen F-bods who have gone 200+ MPH, as they have a similar profile as the Javvy. But power overcomes all...as the Big Red '69 Camaro had the aero of a brick, but still went well over 200 MPH.

That's good. At least you have some idea of where you need to be. J.R. Gottlieb's Big Red Camaro instantly jumped to my brain too. His original power plant was a Lingenfelter prepped all aluminum 540 I think.

What kind of suspension work is done? Lowered?

Peace

[198esp1]

i remember an a c-4 stock body needing 600hp at the flywheel to hit 201 this was in the late 80's junior johnson built the motor.

Originally Posted by 198esp1

i remember an a c-4 stock body needing 600hp at the flywheel to hit 201 this was in the late 80's junior johnson built the motor.

wrong, LT5 C4s were able to hit 200mph stock

[1QWIKBIRD]

I was curious what it would take to push the AMX through the air at 200 mph. So I did some searching and found this:

A calculator for determining the HP to push a vehicle at a given speed.

http://www.bgsoflex.com/auto.html In the left hand column is a formula "Aerodynamic and Rolling HP Loss Calculation" So after looking up the width and height of a 70 AMX here http://www.amx-perience.com/pdf/1970...onsBooklet.pdf and doing some math I estimated the frontal area of the car to be (71.57"x51.20")=3664.384 sq. in. Divide that by 144 and you get sq. ft. = 25.447. The web pages says to mulitply the calculated frontal area by 0.85 to account for rounded edges etc. The curb weight is about 3350lbs.

So I plugged in 0.44 as the coeffiecent of drag (per the chart for a 60's muscle car medium drag, on the web site), a frontal area of 21.63 (0.85x25.447), tire inflation at 35lbs, curb weight of 3350 and left all the other parameters set to default and set a speed of 200 mph.

This generated:

Input Parameters Are the Following:

* Coefficient of drag = 0.44
* Frontal Area = 21.63 sq feet
* Test Temperature = 70.00 degrees F
* Test Barometer = 30.00 inches Hg
* Vehiche MPH = 200

Computation Results:
Air Density Computed is 0.00233

Aerodynamic "Drag Factor" is 0.02386

Rolling "Drag Factor" is 80.21060

# Computed Aerodynamic Horsepower Required is 509
# Computed Rolling Horsepower Required is 143
# Computed Frontal Lift Force is 166 Lbs.

If you play with the Coeffiecent of drag and use 0.38 (60's muscle car low drag) instead of 0.44 the power required drops to about 600hp.

So it looks like you need to make about 650 hp to pull this off UBG.....assuming the inputs are reasonably close????? I'd guess that number might be on the conservative side, so shoot for 700hp just to be sure. It would suck to do all this work and only go 198 mph.......

I thought this was interesting, might be completely wrong, but interesting

[1QWIKBIRD]

Originally Posted by JerzLT1

wrong, LT5 C4s were able to hit 200mph stock

Maybe, but none of the mags at the time could pull it off., Not stock lt5 cars.....at least not published data.

http://www.zr1netregistry.com/ZR1_performance.htm

I plugged some numbers into the program in the other post and it looks like you would need at least 500 HP so push a C4 vette to 200mph.

Here's a good discussion on C4 performance and top speed:

http://www.corvettebuyers.com/c4vettes/performance.htm

[SteveR]

Originally Posted by 1QWIKBIRD

I was curious what it would take to push the AMX through the air at 200 mph. So I did some searching and found this:

A calculator for determining the HP to push a vehicle at a given speed.

http://www.bgsoflex.com/auto.html In the left hand column is a formula "Aerodynamic and Rolling HP Loss Calculation"

I've been playing around on that site for the last few days. Great site, thanks for posting that.