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Old 03-19-2011, 04:40 AM
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sbc build

Hey folks-I'm new to this site so play nice!
heres' my problem-
I got screwed on a motor I bought for a mud truck I'm building-worn out 350 4bolt -.30 over dish pistons with old style edelbrock heads . It was supposed to be a 383 but when I opened it up it turned out to be a 350 crank that someone had put a notch into to look like a 400{very low} any way
The heads are nothing real special 70 cc 202/160 closed chamber
My question is- If I run some domed pistons in this can get around 400-425 hp. I'm already upside down with the motor and have to replace the crank.030 under and pistons {dish} Just trying to salvage some the parts that I have! I need the hp to turn my tires but not real high rpms

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Old 03-19-2011, 05:21 AM
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What compression ratio and fuel octane do you want/need to use?
Are you going to install a 3.75" Stroke Crank?
Mud Drag truck?
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Old 03-19-2011, 05:27 AM
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10.1? stock 350 crank freebie replacement Will probably run av gas since its available local
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Old 03-19-2011, 05:35 AM
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A Dome Piston will put you well above 10.00:1 Cr. A small .100" dome/2.4cc would be about 11.39:1 Cr.
4.030" Bore X 3.48" Stroke,
70cc Head, .041" Gasket, 0 Deck Ht.
Flat top 2VR/5cc Piston would be 10.38:1 Cr.
Flat Top 4VR/7cc Piston about 10.16:1 Cr.
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Old 03-19-2011, 05:54 AM
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sbc build

what cr and cam profile am I gonna need to hit my target hp with these heads
remember I'm trying to do this on budget recycled parts,[Yeh, I know there is nothing cheap when it comes to making hp but I'm not looking for space shuttle lift off velocity]
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Old 03-19-2011, 05:58 AM
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do you think I would have to clay a.100 dome piston?
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Old 03-19-2011, 06:08 AM
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Quote:
Originally Posted by Old bones
Hey folks-I'm new to this site so play nice!
heres' my problem-
I got screwed on a motor I bought for a mud truck I'm building-worn out 350 4bolt -.30 over dish pistons with old style edelbrock heads . It was supposed to be a 383 but when I opened it up it turned out to be a 350 crank that someone had put a notch into to look like a 400{very low} any way
The heads are nothing real special 70 cc 202/160 closed chamber
My question is- If I run some domed pistons in this can get around 400-425 hp. I'm already upside down with the motor and have to replace the crank.030 under and pistons {dish} Just trying to salvage some the parts that I have! I need the hp to turn my tires but not real high rpms
The heads will get you he power you want, more displacement will get you more torque- like going to a 3-3/4" crank.

Otherwise, build it w/a solid tappet cam and domes to make the compression to match it. HERE'S a CR calculator. Head gasket diameter is usually around 4.1" for a 350. Shoot for a "quench" figure (piston top, not dome, to head deck distance @ TDC) of about 0.040".

I see you hail from St. Cloud! If you're an "original", you will remember Toms Auto Salvage on Robinson Ave. It's a trailer park now.
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Old 03-19-2011, 06:13 AM
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sbc build

O.K. here's were I get frustrated!! I look a .125 domed piston on ebay{because of a quick selection} and the chart for speed pro says a .125
64cc-10.5
76cc- 9.26
So this math formula is subject to interpretation
Thats kind of why Im here, to get some more experinced advice
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Old 03-19-2011, 06:23 AM
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sbc

If I went to a 3.75 crank can I get there with 2v flatops
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Old 03-19-2011, 06:23 AM
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Use the calculator. You'll need to know the head gasket dimensions, how far down the hole the piston is at TDC, the chamber volume (needs to be CC'd to know exactly what it is), and the published dome volume. The overbore and stroke gets entered, then a answer is given.

The published CR numbers given usually do not specify an overbore size, gasket dimensions or even how far the piston is down the hole.
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Old 03-19-2011, 08:08 AM
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Have a look through these Dynoed Engine combos, there's over 100 to look at. As Cobalt327 said, with the Heads you have you can come up with 400HP, with 350ci using Flat Tops or 383ci using D-Dish Pistons. These provide much better Quench/Squish than Dome Pistons.
Just need to get all your Specs/Details, Cr., Deck Ht., Cam Info etc..
With the aluminum Heads you can run 10.00:1 to 10.50:1 Cr. easily or more with the AV fuel.
Dyno Engines>> http://ryanscarpage.50megs.com/combos1.html

This TRW/SpeedPro list shows more Piston Cr. detail, they're based on a .030" overbore. http://www.flatlanderracing.com/trwchevy350.html

Other Piston Specs, many w/70cc Chamber>> http://www.flatlanderracing.com/pistons.html
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Old 03-20-2011, 06:33 AM
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sbc build

Thanks for all the friendly input guys-It created a little more clarity to a clouded mind!! - BUT MADE MY HEAD HURT
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