Dart BBC Tow Rig Setup

[fzsk4p]

Hi folks,
first post here.
Looking for a bit of advice/direction on a Dart based BBC for a DD/tow rig.

First a history lesson ;

Back in my working days (retired now) had the pleasure of driving several company concept trucks based on Chevy Suburbans. Ones made for foreign government evaluation/use. Several of these `Burbs had Lingenfelter BB`s that were simply awesome. Talking close to 600 inches. Idle all day in traffic and then give one helluva rush when the fun pedal was pushed. Linear powerband, no crankiness or bad habits. Hell my wife would drive it too the grocery store. Her only comment was that it seemed to have a little miss at idle. Really enjoyed the ride home from work with those kids in there Z28`s and Mustangs. Imagine getting shut down by a big butt Suburban.

Fast forward to today;

Late 90`s 3/4 ton 4wd Suburban as the runner. 4L80E, 14 bolt geared to the engines torque curve. Typical driveline upgrades.

Looking to build a Dart BB to use in this `Burb. Emphasis on towing (7000 lbs) and driveability. Overkill I know but hey.........:D

Thinking along the lines of around a 572 with Brodix -2x heads. High lift moderate duration cam. Enough lobe separation to draw decent vacuum at idle.

Typical headers/exhaust etc.

Any ideas on a good setup ? 572 ? short of tall deck ? Head choice, cam ? Intake FI, carb ?

I have a fair amount of engine building experience but nothing like this.
SBC`s, SBF`s, Pontiac`s, L36SC, L81, LA1 etc.

Last engine built was a .080 over Jeep stroker with an off-set ground crank, Eagle rods, Diamond pistons etc.

This Dart project is something I need some help with. Most folks (seems) are trying to get a bunch of power at what I would say is a higher RPM then what I am looking for. Want a good torquey muscle motor with good manners.

Thanks much !!

[want-a-be]

fzsk4p,

We would be more then happy to help out. I sent you a pm.

Let us know how we can help out.

Don

[Awesome Bill]

A really nice 581 4.6 bore x 4.375 stroke would be your killer short deck. Don't use the BB2 heads they are too big for your applicaiton, your going to kill you bottom end.

I would assume you would like to run this thing under 5000 rpm and cruise at about 2000 rpm pulling and make about 800lbs torque? Dart 310 head in my book would be too big but will work. The oval port with some modifications would be the best.

As far as the camshaft, I would stay away from anything over 240° duration and would most likely shoot for around 226°.230° with a little rumble on the idle. I would not want that much noise. This is ofcourse if your going to run a smooth idle and 500-600 rpm in gear.

The fuel injection would be very good and will work with the some of the stuff you have now with some upgraded injection and a little tuning. I can help with this combination if you would like and you would have more power than any tranny you could build will stand when pulling just 7000lbs.

You could run just about 10-1 compression with the aluminum head version. Keeping it cool would be not problem. Let me know.

[fzsk4p]

fzsk4p,

We would be more then happy to help out. I sent you a pm.

Let us know how we can help out.

Don

A really nice 581 4.6 bore x 4.375 stroke would be your killer short deck. Don't use the BB2 heads they are too big for your applicaiton, your going to kill you bottom end.

I would assume you would like to run this thing under 5000 rpm and cruise at about 2000 rpm pulling and make about 800lbs torque? Dart 310 head in my book would be too big but will work. The oval port with some modifications would be the best.

As far as the camshaft, I would stay away from anything over 240° duration and would most likely shoot for around 226°.230° with a little rumble on the idle. I would not want that much noise. This is ofcourse if your going to run a smooth idle and 500-600 rpm in gear.

The fuel injection would be very good and will work with the some of the stuff you have now with some upgraded injection and a little tuning. I can help with this combination if you would like and you would have more power than any tranny you could build will stand when pulling just 7000lbs.

You could run just about 10-1 compression with the aluminum head version. Keeping it cool would be not problem. Let me know.

Thanks for the warm welcome guys. Have to read the PM, thanks !!

AwesomeBill- You are right on the money. Just the kinda beast I am looking for.

Still have a few (well a bunch actually) questions but we are off on the right foot. :D

Bill, by OP heads are you speaking of say L29`s ?

Thanks again. This looks like a fantastic source of information to tap into.

[fzsk4p]

Awesome Bill,
Just looking around based on your comments.
You mention the Dart 310. The aluminum with 310/119 chambers.

How about the iron head with 308/121 chambers ?

Better heat dissipation with the alumminum is you logic ? As the runner/chamber sizes are so close.

Again you mention Oval Port Suspect you are referring to these.

https://store.gmperformanceparts.com/store/SelectProd.do?prodId=7574&redir=true&manufacturer=GM&category=Cylinder%20Heads&name=Bowtie%20Oval%20Port%20Aluminum%20Cylinder%20 Head%20Assembly%20&model=<!--12363392-->

Or maybe these 572 heads

https://store.gmperformanceparts.com/store/SelectProd.do?prodId=7664&redir=true&manufacturer=GM&category=Cylinder%20Heads&name=Bowtie%20572/620%20Cylinder%20Head%20Assembly%20&model=<!--12499255-->

Understand we would want to keep intake velocity high so a smaller volume runner would make sense. However going too small will sacrifice power as the engine will not be able to breathe. These are some of the areas that I will need help. Just not familiar enough with big inch engines to make a good call. Same goes for matching the head and camshaft, compression.


Thanks !!

[Awesome Bill]

Either the 308 steel head or the 310 Pro 1 would be a perfect match. With the steel head, I would polish the chamber so no detonation would occur. The aluminum version would only help with detonation and that is why I said that. With 10:1 compression, you would most likely not have any problem. 9:1 would be idea and you could run 87 octane and still peg the torque meter.

Any size BBC like this would be an animal and with the smaller Oval Port heads, with a 2.25 intake and 1.90 or so intake valve, you could use the older late 70's early 80's and you would still have an animal. It is just nice to have the newer port designs with the Dart Oval port fully ported aluminum head.

We have run those in race applications and they do better than anyone even thinks they could. We just tighten the converter up a bunch and run it to 6000 rpm and the et stays the same with way less rpm. The torque curve never goes below 600 even @ 2000 rpm. Big runners kill bottom end.

This truck is not needing anything over 4000 rpm to do its job and make decent fuel economy. You will only be using 1/3 throttle at any time with this to do its job. No one wants to spin an engine, tranny or gear set over this anyway.

TORQUE cannot be replaced with HP in this application so forget anything big. If your serious, my business # is always available. We just done a 565 Street Heat Series engine with a 320 head for a Marine application and the torque was almost 820 and power was 787 @ 5500rpm. 9.5:1 pump gas with a 850 Ultra HP dual plane Hyd roller. Broke the outdrive first time he got in it. Fixed that and he has one of the fastest boats on Anna Lake!

[fzsk4p]

Either the 308 steel head or the 310 Pro 1 would be a perfect match. With the steel head, I would polish the chamber so no detonation would occur. The aluminum version would only help with detonation and that is why I said that. With 10:1 compression, you would most likely not have any problem. 9:1 would be idea and you could run 87 octane and still peg the torque meter.

Any size BBC like this would be an animal and with the smaller Oval Port heads, with a 2.25 intake and 1.90 or so intake valve, you could use the older late 70's early 80's and you would still have an animal. It is just nice to have the newer port designs with the Dart Oval port fully ported aluminum head.

We have run those in race applications and they do better than anyone even thinks they could. We just tighten the converter up a bunch and run it to 6000 rpm and the et stays the same with way less rpm. The torque curve never goes below 600 even @ 2000 rpm. Big runners kill bottom end.

This truck is not needing anything over 4000 rpm to do its job and make decent fuel economy. You will only be using 1/3 throttle at any time with this to do its job. No one wants to spin an engine, tranny or gear set over this anyway.

TORQUE cannot be replaced with HP in this application so forget anything big. If your serious, my business # is always available. We just done a 565 Street Heat Series engine with a 320 head for a Marine application and the torque was almost 820 and power was 787 @ 5500rpm. 9.5:1 pump gas with a 850 Ultra HP dual plane Hyd roller. Broke the outdrive first time he got in it. Fixed that and he has one of the fastest boats on Anna Lake!

Bill, thanks again for the reply.
You obviously have your arms around these big inch engines.

One question-What are you doing for intake on these 581`s ? Is it still FI and are you using OEM ECM`s. Or some other type of system ? How about the manifold itself ?

About ready to pull the trigger but want to understand the feeding of such a beast.

Not that it would be a big issue but what kind of mileage could one expect with one of these 581`s ?

[Awesome Bill]

we use the stock GM and FAST systems for a total work over. Any RPM air gap style intake is fine. Believe it or not over 16mpg with the big ones all the time. Drive it like a mainiac and you won't get 10

[fzsk4p]

we use the stock GM and FAST systems for a total work over. Any RPM air gap style intake is fine. Believe it or not over 16mpg with the big ones all the time. Drive it like a mainiac and you won't get 10

Bill, thanks again for the prompt reply.

Yes I am a bit surprised that a big inch engine does so well in fuel economy. Can only imagine what driving with a heavy foot would be like. Not to mention rear tires and tickets. But hey we do need to clear it`s throat once in a while, `eh ?

Want to make a guess on what a 0-60 or a 1320 time might be ? Lot`s of variables for sure but a ball park would be salivating. ;)

After finally having some time, read many of the messages in the forum. You seem to be very well respected and your comments carry a wealth of knowledge.

Be in touch very soon for getting a build started.

[rusty]

Do you have one of these engines built yet? Thinking of building a 572 for my tow vehicle, regularly gross between 11,000 and 15,500lb. Thinking of 4.5" bore and stroke, hyd roller cam, possibly performer intake- have one on current 454, I have alloy heads with 2.25" int 1.88" exh. I figure if the tierd 454 pulls 11,000lb easy enough at lower revs a 572 built for low speed power should be able to pull most of the time at 15-1700rpm set up with an overdrive behind th400.
Very interested how you found it, power and even mileage.