Builds dougbert's future 350 swap: How much torque is too much? (2 Viewers)

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Edelbrock makes a very nice dual plane manifold specific to Vortec heads. I have been using one for the past ten years. It currently sports a home made (ok, red neck) TBI adapter plate and big block throttle body.

Norsk, I think you may find more usuable torque and certainly better economy with a cam that has no more than 212 degrees at .050" The larger cams make more torque, but not really the type of power you can hook up the a 5000# trailer and be happy. They're great for hot rods, but not always for trucks. The overlap is very effective for cylinder charging at low RPM, but you pay a penalty with mileage and heavily loaded operation. The overlap is not good for use with FI, which as I recall, you plan on doing sooner or later. The unburned fuel that makes it out the pipes due to the overlap tells the FI to go leaner which is really doesn't need to do in that case. Go with a roller cam and go with some good lift, moderate duration. Just my random thoughts...

I think that is the Edelbrock manifold I am referring to. There is a spreadbore to TBI adapter that fits just nice on the manifold for later.

The CAM choice HAS been highly subject to change in my build design.

I have been jumping between 2 of the CompCAMs (all the CAMs are hydro Rollers - I will also be using full self aligning rocker arms too):

The more milder one
12-411-8 which has 210/214 @ .050
COMP Cams: Xtreme 4x4™, X4260HR <BR> Good Mid-Range, Good Performance Increase

and the
12-413-8 which has 220/224 @ .050
COMP Cams: Xtreme 4x4™, X4260HR <BR> Good Mid-Range, Noticeable Idle

both have Lobe Separation Angle at 111 and Intake Centerline at 107. Lift on both is .474 with 1.5 rockers.

I think because I told the CompCAMs tech I had 4.11 gears, he recommended the 220/224 which has a power range of 1500 to 5500

The 210/214 cam has 1200 to 5200 range.

I have looked at the valve overlap for them on the Simulator, but don't remember them at the moment, but will get them on there after I get home.

BTW: That Dyno Sim5 has given me alot of insight into what various configurations can do.


(EDIT: The following CAM is the one I installed)

A more mild CAM is the 12-409-8
COMP Cams: Xtreme 4x4™, X4258HR <BR> Strong Torque, Good Mileage

Its specs are 206/210 @ .050, same LSA and ICL as the other two. But it only lifts to .458 and with a Range of 1000 to 5000 RPM. I think this is the one you indicated you had in your truck

It does say it has good torque and good mileage. I haven't run its numbers thru the Simulator yet. I will do that and report.

I have found this to be a great "hobby" at my age and stage of life, and it is centered around the FJ60. It has been 40 years since I had a dream to do this, but 6 kids, and other things kept be busy and broke before this time.

I do plan to play with FI later, and I have NO problem pulling the CAM and putting one that is FI friendly in as you mentioned later. I am putting a two piece timing cover on it so I don't have to crack the oil pan to do so.

Yet, I may yet decide to put in the mildest CAM at first, if input from you and others points that way. Its all in design stage now. (Well, not the head, that is at the machine stop, but I still have time to change the design. Looking for options.

thanks for the input, ALL of these comments help.

Please if others have question or comments, please post, I have having fun learning and actually DOING THIS.

dougbert
 
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Those are not the heads, and it looks like the heads I had in mind have been dropped. Not finding them on the GMPerfParts page. What I had found is a aluminum replacement head for some year Corvette that had a 165cc intake port. With that small intake port volume they would've worked really nicely on a low rpm 350.

okay,

The ones I am looking are $520 including shipping. They have 185cc runners

GM Performance 25534421 GM Performance Parts SB-Chevy Bowtie Vortec Cylinder Heads

which several articles indicate almost equal the performance of the alum ones and are much cheaper.

My static CR is at 9.8:1 and dynamic is looking to be around 7.8:1 with larger CAM. I need to see what the DCR would be with the milder CAM

dougbert
 
my view..I would want the "power-band"...the initial torque sweet spot to be a close to off-idle as possible and maybe max around 3K-4K... thats going to be where all the off road stuff happens... the more power / torque you can make around 1000RPM-3000RPM will be to your advantage.

I was leaning towards a 383 myself....great setup.

Good idle, pump gas, torque monster, low relative rpms and you'll be where you want. Transmission gears and differential gears and transfercase gears will need to be part of that equation.
 
my view..I would want the "power-band"...the initial torque sweet spot to be a close to off-idle as possible and maybe max around 3K-4K... thats going to be where all the off road stuff happens... the more power / torque you can make around 1000RPM-3000RPM will be to your advantage.

I was leaning towards a 383 myself....great setup.

Good idle, pump gas, torque monster, low relative rpms and you'll be where you want. Transmission gears and differential gears and transfercase gears will need to be part of that equation.

Great input, thanks

I will put down my entire design here as well I guess, at least all the major components and their price.

dougbert
 
Here is a DynoSim5 window image, when configured with 383 motor 4.040 bore, CompCAMs X258HR Roller cam, 206/210 @ .050 .458 lift and the GM Bowtie Vortec small runner heads, Large Headers with cat and muffer.

This puts out more torque than the prior two - wow

TQ is 549 @ 2000 RPM at sea level
HP is 349 @ 4500 RPM at sea level

this is impressive

dougbert
383-X4258HR-GM-Bowtie-SmallRunner.jpg
383-X4258HR-GM-Bowtie-SmallRunner-data.jpg
 
I would skip the 383, the amount of extra machining will add up and not be worth it on a heavy off road vehicle. You can make plentiful torque and horse power with a 350.

The current motor I am building is a 350 4 bolt main runner out of a 1978 motorhome. My buddy sold me some camel hump heads for cheap. I'll run the base Comp "offroad" cam and a square bore Edelbrock Performer (I run propane).

The cam is really the heart of the motor, I want absolute low end torque and good idle quality. With propane it isn't worth going over 5000 rpm for me.

The iron VORTEC heads are awesome for a budget build.

Dan
 
I disagree. Stroke is always good when dealing with weight. Torque is what moves weight, not HP. And we all know that the easiest way to get more torque is a longer stroke. Or go diesel.....
 
I would be curious what the sim would do with the 3.8 stroke cam from the HT383. Gives you 383 cubes with stock bore. A bit more if your 40 over maybe 389?
 
I would skip the 383, the amount of extra machining will add up and not be worth it on a heavy off road vehicle. You can make plentiful torque and horse power with a 350.

The current motor I am building is a 350 4 bolt main runner out of a 1978 motorhome. My buddy sold me some camel hump heads for cheap. I'll run the base Comp "offroad" cam and a square bore Edelbrock Performer (I run propane).

The cam is really the heart of the motor, I want absolute low end torque and good idle quality. With propane it isn't worth going over 5000 rpm for me.

The iron VORTEC heads are awesome for a budget build.

Dan

actually I have studied what needs to be done to the block to generate the clearance and that is part of my "learning". I will be doing it and part of fab training.

dougbert
 
I love Quadra Jets. They are by far the most tuneable four-barrel carb ever made. They refuse to flood no matter the grade and they can support huge HP numbers when set up correctly. In fact, my TBI, althought it runs SOOOO well, has not yet topped the Q-Jet for best mileage from a tank of gas. It has gotten close, but still shy.
 
there are plenty of proven solutions with the 383 and 350...you dont need a torque monster...but if you did build one that would be fine. Simplicity, reasonable cost, good idle, 9.25 or so true compression...and your're good. A stock 5.7 will push the FJ60 with plenty to spare.

a gm crate motor would be a great solution or a ramjet.

This place has all kind of stuff Pace Performance | GM Performance Automotive/Truck Parts & Accessories

jegs and summit have good selection.
 
357-X4258HR-GM-Bowtie-SmallRunner.jpg
I ran the Sim with the 350 (actually 357 with .040 over) and it comes up with 515 ft-lbs (24 less than the 383) and 354 hp (4 HP MORE than the 383)

I am thinking, that since I am NOT pushing the HP goal, that yes, the 357 version would be adequate, cheaper and simpler. My machinist indicates that on the 350 parts,he can get parts in a custom kit MUCH easier and cheaper than the 383.

(Note that this whole engine design has been very fluid as I find new options, which effect what I will do. But I will say that things are gelling well, and it will be good setup when complete. I am not in a hurry, as I will probably only be able to do this ONCE due to getting old. The journey is part of the joy)

dougbert
 
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I played around with that program. It indicated that mine should be 380 HP and around 420 tq starting essentially from idle. Whatever it is, I love blowing the doors off unsuspecting, pretend SUVs and breaking the speed limit half way to the top of the on ramp.
 
Visited the machine shop and he got my block through the 1st hot tank cycle, still dirty, but got the cam bearings out. Still more hot tank and cleaning to do along with the oil galley plugs to remove.
2012-01-09_13-18-16_100.jpg
 
If you haven't yet, do yourself a future favor and knock all of hte exterior casting flash off the block. I use a die grinder and a 4" flapper on a Makita grinder to knock off and smooth the block. This so when I'm working around the engine there aren't any sharp edges to make me leak.
 
If you haven't yet, do yourself a future favor and knock all of hte exterior casting flash off the block. I use a die grinder and a 4" flapper on a Makita grinder to knock off and smooth the block. This so when I'm working around the engine there aren't any sharp edges to make me leak.

thanks and I did most of it before sending it in. When I get it back, I will examine it again, great advice.

His plans are to:

remove the galley plugs
crank align the mains
deck
torque bore/hone
install cam bearings
internal balance
set new oil plugs
set new freeze plugs

then I get to take it home

and build it part by part. Will mostly pics of that process, then once the power train is done, then the actual swap.

doug
 
Do you have the rotating assembly parts already? He will need the crank & rods to set the main & rod bearing clearances and he'll need the pistons to set the final bore size, and he'll need to know which rings you want to run to put the right hone pattern & finish in the bores.
Brass freeze plugs?
 
Do you have the rotating assembly parts already? He will need the crank & rods to set the main & rod bearing clearances and he'll need the pistons to set the final bore size, and he'll need to know which rings you want to run to put the right hone pattern & finish in the bores.
Brass freeze plugs?

He is ordering all of the above, yes

doug
 

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