tuxnharley

Just make sure you don't get the same results as what Taco Bell food produces.............

uxojerry

SBC uses 23 degree heads versus LS 15 degree heads. Most of the improved mpg of the new cars is from the overdrive transmissions.

I just installed a T56 Magnum 6sp with a final drive ratio of .50. When the car is finished, I will report my mpg from a 427 SBC with computer controlled EFI. Im expecting good results.

Plasticman

That is the head surface angle relative to the valves, not the "V" which is (and remains) 90 deg....

And yes, you can modify Gen. 1 SBC heads to other valve angles.......but then the intake manifold becomes "special".

Only the head surfaces are cut to obtain something other than the stock 23 deg.

And not all LS engines are 15 deg. Read this:

The big leverage point for the LS series of engines has always been excellent cylinder heads. Every LS production head features no worse than 15-degree valve angles (the standard small-block Chevy valve angle is 23 degrees), and more recent LS performance variations have pushed that out to 12 degrees.

Read more: http://www.carcraft.com/techarticles...#ixzz1yXkKZnhb


Plasticman

NOM61

Seems to me that if you take the World block, with a Gen 1 bottom end and an LS top end, add a good aftermarket fuel injection and combine it with a 5 spd and the right rear end ratio, that you would have most of the benefits of an LS without most of the conversion hassels.
The LS bottom end may be more rigid and provide greater reliability under sustained high rpms, but that has no impact on fuel efficiency.
The only possible difference I can see would be if the friction losses and rotating mass were less on the LS bottom end.

DT

toms silver 60

Bill has one of central Florida's largest Dodge minivan (box) collections and is determined to put a Chevy engine in one of them, with the mandatory Chrysler My6 transmission!

out2kayak

Umm, no slam against anyone, but I was going down the World block route and, after much research I decided to sell it (at a loss) and go with a RHS block (http://www.racingheadservice.com/Ins...es/54900IS.pdf).

Engine Mounts: Machined for Gen III & front engine mounts, provisions for Gen 1 mounts are spot drilled and will require drill and tapping and may break into waterjacket. In the event that these holes break into the water jacket, apply sealant to these fastners. We also recommend installing a flush stud into the Gen III hole adjacent to the Gen 1. Hold to add backup for the bolt. Also provisions for front motorplate race mounts.

Look over on http://ls1tech.com/forums/ for what folks have found on the Warhawk block, sleeves, customer service, etc. and then contrast it to RHS.



-- Joe

wmf62

i'm talking C1s, which has the aerodynamics of a brick....

that has not been my experience so far, the BEST i've gotten on the highway might be 21-23 while an LS can get 28-30 (so i'm told)
Bill

NOM61

Since you have to weld in mounts in a C1 anyway, what difference does it make if they are Gen1 or Gen3 mounts? The important thing is being able to use all the old accessories, the bottom end and the bellhousing.

DT

uxojerry

The LS motor can do a lot of things better than an SBC. SBC technology is also evolving. To me it boils down to simplicity versus hi-tech. The LS motors are great until they have a problem. Many of the problems are both computer and mechanical, requiring computer and dyno diagnostics. Many C5/6 owners know their rwhp because the car is dyno'd during tuning. Most C1-C3 owners do not know their rwhp because a dyno is not required for tuning. Dyno tuning generally starts around $500.

The modern SBC EFI systems come with self learning mini-computers. When my motor was assembled and dyno'd, the guys watched the numbers change as the computer was analyzing and adjusting things for better response. That sounds like reasonable technology to me.

The LS is a better motor, with the tradeoff of more technology. 8 coils versus 1, engine management computer for a multitude of inputs to include transmission, etc. Things may not go wrong very often but when they do, they can be expensive to diagnose and difficult to fix.

My view is the minority. Most engine polls on other forums run 80/20 in favor of an LS over SBC. Im also one of the guys who would have complained when the M14 was replaced with the M16, lol.

wmf62

for some of us that is the most important thing, being able to use beloved Gen I 'accessories'... and still be able to reap the benefits of technology


Bill

uxojerry

The C6 Z06 has a rear diff gearing of 3:42 and a 6th gear of .50. 5th gear in the Z06 is .74. Most C1-C3 transmission conversions choose a 5sp with a 5th gear of .75 or so. Lots of old Corvettes have rear diff ratios higher than 3:42. MPG of LS and SBC can only compare if gearing is equal. Drive the Z06 in 5th gear all the time and mpg should be similar to the typical C1-3 conversions. 21-23 mpg sounds about right.

An SBC with good EFI and equivalent C6 Z06 gearing, should get mpg approaching that of an LS7 equipped Z06. As soon as my car is finished, I will be able to verify this. I have almost the exact same gearing as a C6 Z06 and am running a SBC 427 with a very good EFI.

If my $20k+ experiment does not work, I will freely admit it. My motor will still be pretty to look at,lol.

checkmate

It is a very easy computer to learn making it very easy to diagnose. The shop manual for my 99 Camaro is just as easy to follow as the one for my 1954 Corvette. The few electrical issues I've had on my camaro I've been able to diagnose with a multimeter and that shop manual. I've used that same multimeter on the corvette checking grounds and power.

I taught myself how to tune ls1 cars the same way I recently learned how to rebuild a carburetor, reading, watching videos on the internet and not being afraid to learn something new.

wmf62

yep, i have a pretty engine tooooo... $$$$

with a 3.36 rer and a .73 od i have an effective 2.45 rer, BUT it takes a ton of low end torque AND aerodynamics to pull that with any 'economy'
Bill