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Author Topic:   what size engine
Scoot
Dirt Freak

Total posts: 330
posted April 28, 2002 01:17 PM
What size engine do you guys have in your street stocks? Bore size, heads, intake? I started out going to race in hobby, but I got bumped up to super stock because of not pulling vaccum. The engine I have is a 355 with flat tops and 624 heads. I'm looking to build a different motor. Need to know what I need to be more competitive.

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Scoot
Smith Racing Team
870-365-5989

Radrcr869
Dirt Full Roller

Total posts: 30
posted April 28, 2002 04:55 PM
Scoot Not pulling enough vacuum is usually due to the Camshaft. Do you know what size is in it ? I know where I run we are limited
for chevy to a 350 with a 030 over Bore and only a certain Casting number for the Heads
Valves must be 11/32 stem diameter. Intake must be cast Iron 2 barrel Unit w/ NO Mods
and we must use Cast Iron Exhaust Manifolds
Cam can be Any Hydraulic but SOLIDS not allowed So check around for some other Cam Ideas ?

Scoot
Dirt Freak

Total posts: 330
posted April 28, 2002 05:06 PM
I was told it was a 292 but I have no idea about anything else. They've put me in super stock from the start and i'm 5th in points out of 9 cars. I'm just gonna stay in this class and learn as I go. I'm mainly working on my setup to get through the corners now. But I know I'm gonna need alittle more motor. The other guys have just alittle on me it looks like.

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Scoot
Smith Racing Team
870-365-5989

Flatlander
Dirt Freak

Total posts: 310
posted April 28, 2002 09:43 PM
What kind of parts you got in the 355 lighten it up get a cam roller rockers a good set of heads manifold and carb and build omn your base set up you have the parts why waste them and you can add a little at a time so you will know the diff and then you can identify weakness later on and help your self

Scoot
Dirt Freak

Total posts: 330
posted April 28, 2002 09:55 PM
That's what I've been debating. Alot of people have told me to get Dart heads. I've almost decided on Pro Topline "Lightning" heads. They are coming out with a 50cc head in May. I've also decided to get a Super Victor Intake. I've already bought a carb off Kinetic Performance. I have roller tipped rockers now, Is there alot of difference with full rollers?

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Scoot
Smith Racing Team
870-365-5989

EVANSRACING24E
Dirt Forum Racer

Total posts: 80
posted April 28, 2002 10:23 PM
scoot i run a 355 with 58cc heads(old cast performance heads with no holes) than have been worked on, stock aluminum intake with a 2 barrel, solid 535 lift cam both sides 108 lobe seperation(can't remember duration), and flat tops. so far i've been competitive if i can get the car to handle better.

Flatlander
Dirt Freak

Total posts: 310
posted April 28, 2002 11:25 PM
anything you can do to reduce friction and lighten the rotating mass will create HP

Dunbar
Dirt Maniac

Total posts: 119
posted April 29, 2002 08:23 PM
I run a 408 512 horsepower, dart heads, dual line holley carburator, aluminum intake. i'm running 9th in points out of 40 cars...

Pickel
Dirt Forum Champ
Total posts: 564
posted April 29, 2002 08:39 PM UIN: 25419780
I run a 355 with 11-1 comp. camel hump heads cast iron intake that has had work done to it and I am pretty competitive with it.

Dixon
Dirt Full Roller

Total posts: 45
posted April 29, 2002 11:47 PM
Scoot,

Using the full roller rockers will help you in several ways. First, the greatest amount of friction is created at the rockerarm's pivot point. A roller bearing pivot has much less friction than a ball-pivot, so if you're trying to free up horsepower that's where it's going to happen.

Second, with the reduced friction also comes the advantage of not having to pump as much oil onto the top-end of the motor. In Smokey Yunick's book, "Power Secrets" he says that if you use full roller rockers, and get them properly aligned, you can cut off the oil sent to the rockers. I know that sounds crazy, but he claims that with a "reasonable" cam, the valvetrain will be fine up to 7500 RPM. He does say that this will only work for "short races", and he doesn't specify what that means, but that book is dedicated to endurance racing, specifically the kind of mileage the Winston Cup engines see. So if you're running around 20 laps at a time it might be something to consider. Doing this will reduce drainback problems, increase oil control, reduce oil temps, and allow more oil to stay in the main and cam bearings with less oil pressure(free hp).

Third, because of the design of the pivot, roller rockers can have different ratios and still look pretty much the same because the pushrod cup can be set to different lengths. What it means is that you can use higher ratio rockers and mount them on the stock studs, just be careful to check your clearances.

I know some of this may start some controversy, but sometimes we need as a learning tool. I really admired Smokey Yunick and I treat his knowledge of engines as gospel. If anybody thinks different about these ideas I'd love to hear it. I want to learn too. Hope this helps.

Dixon

Dixon
Dirt Full Roller

Total posts: 45
posted April 29, 2002 11:50 PM
Just trying to put that flame on the message.
Dixon

Dixon
Dirt Full Roller

Total posts: 45
posted April 29, 2002 11:52 PM
Maybe it'll work this time.

Dixon

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