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Another Forged 383 Vortec build

 
skinnyz
V-6 Camaros rule!
Posts: 49
Joined: 12/07
Posted: 04/25/10 11:21 AM

I've been researching components and other builds and am narrowing down the parts list.
It only makes sense (to me) when rebuilding a 350 block to make the step up to more cubes.
To quote my engines professor back when I was in college "To go fast on the street, put the largest engine you can between the fenders." While I'm not about to mothball my 4" bore block (in as much as I'd like to build a 400 or 427), the 3.75" crank seems like a logical step.
The problem lies in having a reasonable compression ratio while potentially reusing my 64cc Vortec heads. At least in the interim. Aluminum heads are inevitable.
In trying to keep with the "Made in the USA" theme I often preach about, I've come up the following:
Howards forged crank.
http://www.summitracing.com/parts/HRS-353757TS2/
Howards rods. 5.7" I-beam.
http://www.summitracing.com/parts/HRS-SL5700/
SRP pistons.
http://www.summitracing.com/parts/SRP-139628/
Rings and bearings will be furnished by the machine shop.
While I'm confident the crank and rods are more than up to the task, I have very little feedback on the pistons. They are forgings however with what I've learned, todays metallurgy allows tighter piston clearences than back in the day and the associated problems that accompany it.
My attempt is to keep my static compression ratio at or just under 10:1.
With the proper deck height (.015") and head gasket (.025") I can maintain a decent quench with the SRP pistons. They have have a quench pad (rather than a full dish) and come in at 16cc piston volume.
Using my existing XR276HR cam, dynamic compression is also reasonable at around 8:1. Slighly less if I consider the slight increase in duration with the 1.6 ratio rocker I currently use.
I intend to keep engine speeds below 6500rpm. I understand the heads are a little on the small side to make power beyond 5500rpm or so.
It is a more or less daily driver however it will see it's share of drag strip duty as well as a few open road course events.
Any other builds out there that compare?  

Post Reply
ethelkilledfred-#001
I mow my lawn and find Chevys
Posts: 1371
Joined: 03/10
Posted: 04/25/10 05:21 PM

Icon Quoteskinnyz:
I've been researching components and other builds and am narrowing down the parts list.
It only makes sense (to me) when rebuilding a 350 block to make the step up to more cubes.
To quote my engines professor back when I was in college "To go fast on the street, put the largest engine you can between the fenders." While I'm not about to mothball my 4" bore block (in as much as I'd like to build a 400 or 427), the 3.75" crank seems like a logical step.
The problem lies in having a reasonable compression ratio while potentially reusing my 64cc Vortec heads. At least in the interim. Aluminum heads are inevitable.
In trying to keep with the "Made in the USA" theme I often preach about, I've come up the following:
Howards forged crank.
http://www.summitracing.com/parts/HRS-353757TS2/
Howards rods. 5.7" I-beam.
http://www.summitracing.com/parts/HRS-SL5700/
SRP pistons.
http://www.summitracing.com/parts/SRP-139628/
Rings and bearings will be furnished by the machine shop.
While I'm confident the crank and rods are more than up to the task, I have very little feedback on the pistons. They are forgings however with what I've learned, todays metallurgy allows tighter piston clearences than back in the day and the associated problems that accompany it.
My attempt is to keep my static compression ratio at or just under 10:1.
With the proper deck height (.015") and head gasket (.025") I can maintain a decent quench with the SRP pistons. They have have a quench pad (rather than a full dish) and come in at 16cc piston volume.
Using my existing XR276HR cam, dynamic compression is also reasonable at around 8:1. Slighly less if I consider the slight increase in duration with the 1.6 ratio rocker I currently use.
I intend to keep engine speeds below 6500rpm. I understand the heads are a little on the small side to make power beyond 5500rpm or so.
It is a more or less daily driver however it will see it's share of drag strip duty as well as a few open road course events.
Any other builds out there that compare?


Google and search button can be your friend-

To read the whole story click here>
http://www.hotrod.com/techarticles/383ci_chevy_small_block_build/index.html

383ci Chevy Small Block - New & Improved!
Can A New 383 Be A Feasible Economic Alternative To A Junkyard Jewel?

From the June, 2009 issue of Hot Rod
By Terry McGean
Photography by Terry McGean, Jim Brown, Jeff Koch

...the short-block completed, we had to pick the respiratory organs that would help us achieve the best bang for the buck. We looked for the least expensive combination first. The cylinder heads are key to power production and to economic success; finding a set that can pass air as readily as they fit the budget is the trick. Of course, we didn?t want to hinder the engine?s potential by being too cheap, so we came up with three sets, all of which could be considered affordable, depending on the budget. All of the heads we used will create a static compression ratio of around 10.5:1 with the Powerhouse pistons. That?s a little steep for pump gas, but we opted to forgo custom machine work and forge ahead. The 92-octane test fuel posed no problems.

We?d set the engine up in its mildest configuration, then mount it to the JMS engine dyno and chart the results. From there, we would upgrade the heads and cam in steps, noting the additional cost and as well as the improvement in performance...


Phase III

...On our junkyard 350, the late-model Vortec iron heads had boosted output by nearly 55 hp over the TPI heads, which used the same valve and combustion chamber sizes as the Vortecs, as well as the ?64 heads we just ran. Our synapses were popping in anticipation.

We swapped the cylinder heads and installed a set of GM grooved-tip rocker arms, which are required with Vortecs. These stamped steel arms were used as far back as the mid-?80s, and take the place of the guide holes in the head castings to provide valvetrain alignment. The biggest obstacle with Vortec heads is the specific intake manifold, necessitated by the unusual intake bolt pattern. Currently, Edelbrock has four designs for Vortecs: Performer, Performer RPM, Performer RPM Air Gap (dual-planes), and the Victor (single-plane). We struck a balance between power potential and cost with the Performer RPM.

The Vortecs boosted power to 396 at 5,600 rpm, and they brought torque to a new high of 440 lb-ft at 4,200, seeming to eliminate the need for compromise. At 2,800 rpm, torque was over 400 lb-ft. As usual, the Vortec chambers required less timing, taking only 32 degrees to make max power, though a jet size increase to 72/85 was necessary. The JMS crew pointed out that the exhaust gas temperatures (EGTs) were quite even between cylinders, indicating that the RPM intake is an excellent dual-plane design...



Conclusion

Like its predecessors, this experiment could be deemed a success. We?d started with junk, refurbished it with proper machining and new components, boosted displacement, made a bunch of power, and still hadn?t cracked the $2,000 bank. For street use, we?d probably step back on the cam a couple notches, sacrificing a little horsepower to gain more torque and a smoother idle, but even in relaxed trim, this engine would likely provide enough motivation for 12-second e.t.?s in a typical Nova or Camaro. In fact, we?ll be trying that out real soon.

 
-

Brotherhood of Street Racers

My Space Brotherhood of Street Racers
http://www.myspace.com/brotherhoodofstreetracers

BSR-International
http://bsr-international.ning.com/

ethelkilledfred-#001ethelkilledfred-#001

Post Reply
tuffnuff
Moderator
Posts: 7841
Joined: 12/09
Posted: 04/25/10 05:30 PM

+1,,,
Nice post EKF,,, again.
How about using all that info in a thread, that you could start.
I think the info is excellent and current, for most penny jar budgets.
Mebbe think about it and do a bunch of newbies,,, a lot of good.
Grin  
When The Flag Drops.,.

tuffnuff

The Bull ***t Stops.,.
tuffnuff

P. Engineer, Engine Builder

Post Reply
gettnlarge01
I mow my lawn and find Chevys
Posts: 3330
Joined: 09/09
Posted: 04/26/10 03:28 AM

+1  
luck is when skill and opportunity meet

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Pontiacman2
Moderator
Posts: 8956
Joined: 09/08
Posted: 04/26/10 06:35 AM

+2  
Pontiacman2
Pontiacman2

Professional Hi-performance engine builder

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skinnyz
V-6 Camaros rule!
Posts: 49
Joined: 12/07
Posted: 04/28/10 03:51 AM

I probably spend more time "googling" than anyone has a right to yet that's one article I haven't seen.
Sometimes you just have throw a question out there and see what you get.
Thanks for that.
Having just read the article I'm happy to see the 10.5:1 SCR and 92 octane fuel in the same sentence (in a good way).
I've been running a Vortec headed 350 with 10:1 and a XR276HR cam and besides having to run 94 octane, it's been trouble free.
It's encouraging to see that I can probably get away with over 10:1 and not suffer from detonation.
Anyone with similar experience?  

Post Reply
ethelkilledfred-#001
I mow my lawn and find Chevys
Posts: 1371
Joined: 03/10
Posted: 04/28/10 04:15 AM

Icon Quoteskinnyz:
I probably spend more time "googling" than anyone has a right to yet that's one article I haven't seen.
Sometimes you just have throw a question out there and see what you get.
Thanks for that.
Having just read the article I'm happy to see the 10.5:1 SCR and 92 octane fuel in the same sentence (in a good way).
I've been running a Vortec headed 350 with 10:1 and a XR276HR cam and besides having to run 94 octane, it's been trouble free.
It's encouraging to see that I can probably get away with over 10:1 and not suffer from detonation.
Anyone with similar experience?


I have built a few with @ 11:1 or more and a fairly large cam and it ran great and sounded mean. One was in an El Camino and one was in a Vega to name a few.


Big Cam Vega and Chevelle
Direct link- http://www.youtube.com/watch?v=VGrIoK4bX6I
Default  
-

Brotherhood of Street Racers

My Space Brotherhood of Street Racers
http://www.myspace.com/brotherhoodofstreetracers

BSR-International
http://bsr-international.ning.com/

ethelkilledfred-#001ethelkilledfred-#001

Post Reply
skinnyz
V-6 Camaros rule!
Posts: 49
Joined: 12/07
Posted: 04/28/10 02:29 PM

The large cam makes the difference.
My little 276 allows for quite a bit of compression pressure which is why I'm a little shy of running over 10:1 static. My dynamic compression would run about 8.2:1.
I find that's borderline for pump gas.  

Post Reply
ethelkilledfred-#001
I mow my lawn and find Chevys
Posts: 1371
Joined: 03/10
Posted: 04/29/10 03:27 AM

Icon Quoteskinnyz:
The large cam makes the difference.
My little 276 allows for quite a bit of compression pressure which is why I'm a little shy of running over 10:1 static. My dynamic compression would run about 8.2:1.
I find that's borderline for pump gas.


Do what works for you, if you want to learn, try one thing different and see what happens.

I like this cam-
Magnum, 286HR
Great for Street Machines, Rough Idle
Code: 12-450-8
Price: $303.57

But this is the cam I would use but I don't recommended it for you though, takes more tunning-
Magnum, 314HR
Limited Street Use, Radical Idle
Code: 12-470-8
Price: $303.57  
-

Brotherhood of Street Racers

My Space Brotherhood of Street Racers
http://www.myspace.com/brotherhoodofstreetracers

BSR-International
http://bsr-international.ning.com/

ethelkilledfred-#001ethelkilledfred-#001

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skinnyz
V-6 Camaros rule!
Posts: 49
Joined: 12/07
Posted: 04/29/10 04:30 AM

Tuning is not a problem. I've been at it for years.
My 350 (which is currently apart) had excellent AFR's both at cruise and WOT. Managed over 20 mpg consistently on the hiway and still squeezed out an afternoon of 12.7's at 105 after driving to the track. (Through a single muffler that flows about 275cfm I might add!)12.7's may be fast to you however it felt pretty good considering what I put this vehicle through.(I'm not that hardcore)
I will say that a 314 cam would be way too large for my taste. With my current Vortecs, I keep engine speeds below 6000 anyway and could never use what that cam has to offer. My static compression would be much too low as well at only 10:1.
A quick check with a DCR calculator shows that that monster needs better than 12:1 to really do it's job and that would be a completely different engine package for me. (Mileage might suffer at tad too!)
The 286 you mention is a couple of sizes up from my current XR276HR. It might be in my sights when I upgrade to aluminum heads.
Thanks.  

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tuffnuff
Moderator
Posts: 7841
Joined: 12/09
Posted: 04/29/10 08:07 AM

I'm surprised that you are one of the few, who realizes that a sensible street build DOES revolve around flexibility, from idle to full throttle,,, Most, dont recognize the fact, that 95% of "all" driving is under 3000 RPM's and not full bore.
I believe you're on the right track, I bet you will enjoy your ride immensely.
Good common sense rules, most of the time.
Wink  
When The Flag Drops.,.

tuffnuff

The Bull ***t Stops.,.
tuffnuff

P. Engineer, Engine Builder

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skyeking
I mow my lawn and find Chevys
Posts: 2738
Joined: 08/09
Posted: 04/29/10 04:41 PM

And Then there's Murphy's Law ***********************  
skyeking

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skinnyz
V-6 Camaros rule!
Posts: 49
Joined: 12/07
Posted: 04/30/10 04:06 AM

So far Mr Murphy hasn't been around...too much  

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tuffnuff
Moderator
Posts: 7841
Joined: 12/09
Posted: 04/30/10 05:50 AM

LOL
Smile  
When The Flag Drops.,.

tuffnuff

The Bull ***t Stops.,.
tuffnuff

P. Engineer, Engine Builder

Post Reply
skyeking
I mow my lawn and find Chevys
Posts: 2738
Joined: 08/09
Posted: 04/30/10 04:42 PM

HI there,
  Be grateful for small mercies..  
skyeking

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