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sbc 400

 
idrivejunk
I mow my lawn and find Chevys
Posts: 5119
Joined: 12/09
Posted: 04/02/10 08:21 PM

Dang, tuff, how did you know I just picked up five cans of Old El Paso refried beans today? Tongue

Saw an ad for these neato air intake funnels that bolt into your headlight buckets Grin  
idrivejunk

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idrivejunk
I mow my lawn and find Chevys
Posts: 5119
Joined: 12/09
Posted: 04/02/10 08:27 PM

Oh, nvrhappy,

Full roller rockers are an excellent investment, worth the friction reduction. The ones on that link aren't the cheapest. I liked Harland Sharps, but that was on a Pontiac. Don't think they cost quite that much. Shop around and compare Confused

sorry about the distracting tomfoolery, its just what we do sometimes Laugh  
idrivejunk

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tuffnuff
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Posts: 7841
Joined: 12/09
Posted: 04/02/10 08:48 PM

Some of the cars in the bone yard have the flat to round snorkels and I picked up a couple of these plastic jobs for future ram air.
I'm going to run mine from under the bumper with plastic ripple hose for clothes dryers. The stuff comes in 10 foot lengths and its cheap power
Smile  
When The Flag Drops.,.

tuffnuff

The Bull ***t Stops.,.
tuffnuff

P. Engineer, Engine Builder

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ethelkilledfred-#001
I mow my lawn and find Chevys
Posts: 1371
Joined: 03/10
Posted: 04/03/10 03:48 AM

Icon Quotetuffnuff:
tuffnuff:


ekf,,,
I think, wrong, I KNOW, that the early 302's came with 1.5 rockers and that wagon is prolly running 1.6's putting that cam at .500" lift,,, nice sound tho.
Smile




1.5?????? Assuming it's got 1.6, ok, still streetable. I have run 1.65 on smallblocks on the street, and 1.8 on big blocks. My cams have been in .700+ range with 1.5's on small blocks and .800+ with 1.8's on big blocks. I don't recommend this set for no one who is not willing to do the extra maintenance to the engine with these high lift cams. I don't recommend cams other than factory cams cause they are low lift easy maintenance and easy set up cams. I really don't recommend cams anyway cause I have a different view than most and it may not be what people are looking for. I see your recommendations and see them conservative, but conservative works on 95% of the people out there. So keep up the good work. Like I said this aint about right or wrong, it's an exchange of ideas that have worked in the past, not theories that work on a computer, never made any money racing a computer.  
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ethelkilledfred-#001ethelkilledfred-#001

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Pontiacman2
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Posts: 8956
Joined: 09/08
Posted: 04/03/10 04:35 AM

Ya summit has the 1.5 roller rockers for 169 for there brand and they work well.  
Pontiacman2
Pontiacman2

Professional Hi-performance engine builder

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nvrhapy
V-6 Camaros rule!
Posts: 49
Joined: 03/10
Posted: 04/03/10 07:21 AM

$159 is more what im looking to pay if you guys feel confident in the summit brand quality ill pick these up  

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Pontiacman2
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Posts: 8956
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Posted: 04/03/10 10:50 AM

http://www.summitracing.com/parts/SUM-G6905/


I have used these before and they work great.  
Pontiacman2
Pontiacman2

Professional Hi-performance engine builder

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nvrhapy
V-6 Camaros rule!
Posts: 49
Joined: 03/10
Posted: 04/03/10 11:03 AM

ok couple questions as i been trying to find rockers i ran into a couple post that people are saying to run the narrow rockers on the vortec heads so the rockers wont get in the way of the valve cover bolt. also the summit rockers arent self alining what needs to be done to the head so i can run guide plates  

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chevelle83
I mow my lawn and find Chevys
Posts: 2280
Joined: 11/09
Posted: 04/03/10 08:30 PM

To run guideplates the heads have to be milled across the stud bosses and threaded so the area will be low enough(the screw in studs are much longer) and flat so the studs can be threaded in. Any reputable engine machine shop will work your heads, and should not cost much.  

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tuffnuff
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Posts: 7841
Joined: 12/09
Posted: 04/03/10 09:25 PM

+1
Rather than try and explain, I decided to save a bunch of future typing and just plunk all the info now,,,
The one goal that most engine builders share is making the most power for the least money. Since cylinder heads are typically the bottleneck of an induction system, that's where the smart money usually gets spent. This often leads the determined enthusiast to shop through multiple aftermarket cylinder head catalogs until a head that flows big-time air is found for a reasonable price. In 1996, Chevy introduced its Vortec cylinder head on the L31 truck engine and it didn't take long for enthusiasts to bolt them on their engines and find out how good they really are. The cast-iron Vortec heads offer a 170cc LT1-derived port, making them great performance pieces for street engines when tons of torque is key. As the displacement of the engine increases, the torque numbers go through the roof and the horsepower figures follow.

CHP recently bolted a pair of Vortec heads on a 383ci (see "Twister, Part III" on page 96) and made 486 lb-ft of torque at 4,600 rpm and 449 hp at 5,300 rpm. These power levels were achieved using a stock iron Vortec cylinder head featuring 64cc combustion chambers and 1.94-/1.50-inch intake/exhaust valves. The fully assembled factory heads can be purchased from any GMPP dealer including Scogggin-Dickey, Burt Greenwald Chevrolet, and Friendly Chevrolet. Before you go bolting these babies on your favorite small-block, there are a few things you need to consider. The factory Vortec heads use a light, single-wire valvespring with a damper that generates between 70 and 80 pounds of load on the seat. Because these heads are meant to work with a 1.5:1 rocker, their tall valve guides can only handle maximum valve lifts of around 0.420 inch. While the factory-assembled heads are a great choice for the enthusiast looking to build a stout street engine, there are some modifications you should consider for both power and durability.

If you are willing to take on the additional work, the Vortec heads are capable of unleashing 500 lb-ft of torque. Depending on the size of your small-block, the Vortec's 64cc combustion chambers will require a 12-24cc dished piston to lower the compression level down to a pump-gas-friendly ratio. We've used a 1.6:1 rocker with the GMPP Hot camshaft with excellent results, but found that the larger Comp Cams XE 282HR hydraulic roller with 1.6 rockers requires some head modifications to accommodate the taller lift and required bigger valvesprings.

Installing a high-lift camshaft in conjunction with the Vortec cylinder head requires several minor modifications. Increased valve lifts require stronger springs. Comp Cams recommends that its PN 986 double valvespring be used with its XE 282HR camshaft. The Comp Cams PN 986 >> valvespring features an installed height of 1.750 inches, a 1.430-inch od, 0.697-inch id, and a seat pressure of 132 pounds. The larger spring and increased lift figures require opening up the spring-seat diameter of the cylinder head and machining down the valve guide and valve-guide boss to clear the retainer. To keep things simple, Comp Cams has designed an easy-to-use tool that allows you to machine all the necessary areas at home.

Once the heads are machined and the new springs are in place, it's a good idea to replace the weak press-fit rocker studs with screw-in types. Be careful--the type of studs or rocker arms you choose will determine whether or not guideplates are needed. The GMPP screw-in studs don't require guideplates when used with rail-type rockers. ARP screw-in studs require guideplates. To prevent binding, do not use rail-type rockers with guideplates. It's also wise to enlarge the pushrod holes to a 1/2-inch diameter for increased clearance. This is required when using 1.6 rocker arms to prevent scuffing the pushrods against the pushrod hole in the head.

The "Twister Part III" dyno-test shows that the larger 383ci small-block benefited when the valves spent more time off the seat. However, the increased valve lifts would have created a valvetrain stability problem and required stronger valvesprings. When ordering the proper camshaft for your particular application, it is crucial to use manufacturer-recommended parts. But once that's accomplished, these heads are ready to rock and roll!
Wink  
When The Flag Drops.,.

tuffnuff

The Bull ***t Stops.,.
tuffnuff

P. Engineer, Engine Builder

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Pontiacman2
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Posts: 8956
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Posted: 04/04/10 08:16 AM

Cool  
Pontiacman2
Pontiacman2

Professional Hi-performance engine builder

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nvrhapy
V-6 Camaros rule!
Posts: 49
Joined: 03/10
Posted: 04/04/10 08:53 AM

wow thats alot of stuff lol i like the hp reading though. i was hoping to go with self alinging rockers just to make things easier not sure if im up to doing the machining to the heads.  

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tuffnuff
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Posts: 7841
Joined: 12/09
Posted: 04/04/10 08:57 AM

Stay with the 1.5's and you'll be safe,,, stray from that, and read that post again and again, until you understand what/why you are doing what you're doing, right.
Wink  
When The Flag Drops.,.

tuffnuff

The Bull ***t Stops.,.
tuffnuff

P. Engineer, Engine Builder

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Pontiacman2
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Posts: 8956
Joined: 09/08
Posted: 04/04/10 11:19 AM

+1  
Pontiacman2
Pontiacman2

Professional Hi-performance engine builder

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tuffnuff
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Posts: 7841
Joined: 12/09
Posted: 04/04/10 11:32 AM

Pman,,, we always seem to agree, for some reason,,, ahhhhhhhhhhhh, yes, reason, that is the key word.
Almost forgot that it's usually so simple that the answer is often overlooked.
Happy Easter bud
Wink  
When The Flag Drops.,.

tuffnuff

The Bull ***t Stops.,.
tuffnuff

P. Engineer, Engine Builder

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