Going to the dark side

[Super73]

Well, I think I have made the decision to pull the LS out, freshen it up and list it for sale as a turn key deal.

Wireharness + PCM
Throttle Body to Oil pan minus vacuum pump and alternator
Headers
Flexplate
Converter


It might take me a couple years to get what I want but I am looking in to a alum big block (Tall deck 4.50" stroke most likely) and will likely run a megasquirt EFI set up on it with a direct port..


I might be quite quiet around here for a while.

[Marv D]

I suspected something was going on.....

Just don't let this go the same fate as the Camaro!

[regan wilson]

I thought you were going to tell us you were going twin turbo. Even though everyone knows I love Big Motors, why did you decide to go this route instead?

[gomeez63]

How much

[Super73]

Marv,

This is a more recent thing. Been tied up withwork, family and trying to get my shop up.



Regan,

I have always loved the ls platform, and I thought about twins, even bought a pair of 66/67's, wast gates, bov, intercooler cores and controller. While turbos can make stupid power, I want a certain look. A BBC with FI and dual 4500 Throttle bodies is just cool looking. Plus I think a 59x" motor on a single kit should tap my 8.50 cert and end up costing me less.

[tinydb84]

You opening up a shop? Doing what kinda work?

[Super73]

I should call it my big garage... I might do a few things for people I know, but I won't be a business.

[djracer]

Once you go BBC you will never go back. I would run a SBC on the street but for all out drag racing BBC is the only way to go!

[djracer]

Duplicate

[PGSigns]

A good 598 on one 4500 and efi will put you a chunk past your 850 cert with no hit. Should be a fun ride.
Jimmy

[GMR-PERFORMANCE]

Drop me a line on the LS .. Still up in the air to keep it or sell the truck HA HA but selling it is me being upset . not building the LS to start with.. Goal is 1000 to the tire which is not hard with a single turbo today..

[Marv D]

Originally Posted by djracer

Once you go BBC you will never go back. I would run a SBC on the street but for all out drag racing BBC is the only way to go!

The small block (aka BRIGHT side) addict in me wants to argue with Kevin on this,,,, but too many times I've seen the SBC budget double just trying to make what a BBC can on 1/3 the money. Meaning 1000 in a SBC or LS is going to be 6x what it can be done for in a BBC.

(and you have no idea how bad that statement pained me!!!!)

[Super73]

Marv,

The big inch bad a$$ LS motors that make >1,000hp NA cost well in to the $35k range and that isn't the high dollar parts. Seems the 598's can do that with out exotic stuff for half that. But I plan spending a few extra bucks and going alum block. I just can't come to adding 200lbs to the nose...

[PGSigns]

My 557 inch motor with Dart Big M pro block, CNC 355cc heads 4 3/8" stroke 4.500 bore and a single throttle body on alcohol made 915HP and 770 ftlbs of torque. Went 7.40 179 in the dragster. A 598 with chief heads and a single throttle body can make 1100 hp with out a lot of trouble. Not going to take that to put your truck in the mid 8 second range with no hit. We would put 200 passes on the 557 and change the valve springs.
Jimmy
Jimmy

[Super73]

PGA,

I get what you are saying. My buddy Dan built a 540" motor for another friend of mine. It wears box stock cnc heads, steel rods, single 4500 and makes 98x hp at the crank on gas (69x rwhp). It moved his 3,600lb Chevelle to a 9.4x NA.

While a 598" should make 1100hp (call it around 850rwhp), I am not sure that will get me to an 8.50 NA in my current 3,120lb truck. I have been 9.20 @ 144 with roughly that power now (850rwhp). Truck will gain some weight even with an alum big block. Yes, my 60' wasn't there (1.41 on the 9.20 pass) but I still think I will need a kit to do it. Might not be a big one, but probably a tickle.

[PGSigns]

Making HP is one thing but torque moves the weight. Until you feel the pull that a big inch big block and how fast they can get the weight moving its hard to describe. That extra couple hundred foot pounds of torque makes a huge difference.
Jimmy

[Super73]

PG,

Most people dont think of it this way but a N20 hit is instant tq. A 400hp hit at the crank is a lot of TQ as it is 400hp regardless of rpm.

Think of it this way, my verter NA flashes to 4,600 rpm.
My hit is +/- 350rwhp. (20% loss makes that 437hp at the crank)
437hp × 5,252 ÷ 4,600rpm = 498ftlbs

Now I make 400rwtq at 4,600rpm NA (500ftlbs at the crank if you figure 20% loss).

That's roughly 1,000ftlbs at the crank at 4,600rpm. No wonder my verter flashes to 6,300rpm on the big tune up... And yes, I am spraying this 350rwhp hit out of the hole.


I understand what your are saying, and I know my verter is too loose for my current combo (I recently bought a new one and it is still too loose), but I don't think a 598" motor will make more tq NA than my current 418 on a 350rwhp hit (RPM dependant).


I will however be pleasantly surprised if the 598" motor goes faster than 8.8x NA.

[PGSigns]

Yes but it has not been good controllable power that you can manage from release of the brake button. A really good convertor behind that 598 and a chassis setup to manage it and you could cut 2 tenths off 60 foot and depending on gear and tire size be a full second faster at the other end. A data logger will be one of the things you should ad with this setup. I put one of these systems in the last top sportsman car I was tuning and for the money a great system. We found a couple of tenths in that one from the egt and rpm plots. http://www.rpmperf.com/index.php?pag...mart&Itemid=53
Jimmy

[Super73]

Hi Jimmy,

I will run a data logger, have been with the ls for years. Incredible tool if you manage the data properly.

I have no doubt once sorted out the 598 will be faster than my current combo, but I just see it being 0.7 faster. Again, I will be pleasantly surprised if it goes better than 8.8x.

[PGSigns]

I am thinking there is at least a couple of tenths that you did not get out of your old setup with a loose converter and tuning to the better converter.
Jimmy

[regan wilson]

Weight isn't the only factor. The aerodynamics are one of the biggest problems. I've came past people on the top end and they would tell me (I thought you were going to blow me off the track). These trucks don't cut through the wind they push it.

[Marv D]

Amen to that Regan. Even at 120 the 'visor' at the top of the windshield of the 60-66 is like big-ol air brakes! Somewhere I saw a wind tunnel / smoke test on the 66 design and it was INSANE how much backed up and was pushed to the sides of the hood and windshield.
Like trying to throw an apartment complex down track

[hotrod 80]

A buddy of mine has a successful 299" single turbo mod motor deal . He is making the swap to big chevy also . Parts cost and reliability are the main reasons . I can see the budget reasons for the move.

[BR3W CITY]

Originally Posted by Marv D

Amen to that Regan. Even at 120 the 'visor' at the top of the windshield of the 60-66 is like big-ol air brakes! Somewhere I saw a wind tunnel / smoke test on the 66 design and it was INSANE how much backed up and was pushed to the sides of the hood and windshield.
Like trying to throw an apartment complex down track

I wonder how much difference taping a piece of abs, or 1/4 of a pool noodle, up there would do? If you can take up some of that space, its way at the top of the site line, so it wouldn't interfere with vision. Anyone got a wind tunnel? lol

Either case, I face the same challenges. I'm not an all out race truck, but even when your happy in the low 12's-high 10's, that aero starts to hit you hard. I can't get myself to go all-out on lightening, caging etc, because the aero is one thing that is largely unchangeable.

[gomeez63]

Originally Posted by BR3W CITY

I wonder how much difference taping a piece of abs, or 1/4 of a pool noodle, up there would do? If you can take up some of that space, its way at the top of the site line, so it wouldn't interfere with vision. Anyone got a wind tunnel? lol

Either case, I face the same challenges. I'm not an all out race truck, but even when your happy in the low 12's-high 10's, that aero starts to hit you hard. I can't get myself to go all-out on lightening, caging etc, because the aero is one thing that is largely unchangeable.

We kinda mapped some angles of where the wind hits seems like you would gain a little bit of rear down force