Thread: SBC 355 build

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I was recently asked to build a mud truck motor for a friend of mine. I have been searching for a few weeks now what internal parts would get him the amount of power he is looking for. Below I'm listing the parts that I think we are going to use and was wondering if I could get some feed back on how much horsepower we might see out of this build.
Bottom End
Forged crank 4340 3.480 stroke
6" Forged H beam rods
Icon Dome pistons .163/-6.3cc should make 12:1 compression w/64cc heads
Top end
edelbrock victor jr heads
64cc combustion chamber
215cc intake runner
85cc exhaust runner
2.080 intake valve
1.60 exhaust valve

Victor Jr intake Manifold
holley 750

Camshaft

289/288
.553/.561 mechanical roller

1.5 roller rockers

I have built a few flattop piston motors before and have never really put anything bigger than a 510 max lift camshaft. I have been told that I need to check piston to valve clearance. does this cam seem to be big enough that clearance would be a problem? Not that i don't mind checking but if its not necessary then thats one less thing i need to do. Im sure I'm leaving some factors out here but this is my first post here. Thanks

Welcome


You definitely need to check valve/piston clearance because if nothing else( even if you used a stock 359 cam in this build) with those valve sizes, they are relocated in the cylinder heads and the notches aren't in the correct locations and /or big enough for the 2.080/1.600 valve heads--------


Modeling clay, a couple lite checking springs---------

Need piston mfg and part number, cam mfg and part number and whether it was installed straight up by the cam card or advanced or retarded and how much, head gasket mfg and part number, piston deck height (how far the piston is down in the bore at TDC) and exhaust system details so I can run a DynoSim for you. I'll use the head flow figures from the Edelbrock website.

Please be advised that aluminum heads will require thicker composition gaskets (rather than steel shim gaskets) to prevent fretting of the aluminum due to the unequal growth and shrink characteristics between the aluminum heads and the cast iron block, so it takes some engineering to get the block deck height correct with the stack of the reciprocating assembly and head gasket used to get the squish/quench correct (small block 0.035" to 0.045"), with emphasis on "tighter is better".

First choice might be Cometic #C5274 for Edelbrock heads @4.135" x 0.040"
MLS (Multi-Layer Steel) Head Gaskets
Provide maximum sealing performance for today’s high output engines and require no sealants. MLS gaskets are ideal for both aluminum heads to aluminum blocks and aluminum heads to cast iron blocks. They can withstand the shearing force created by the two materials. MLS gaskets have increased strength because they are comprised of multiple layers of stainless steel; which also creates the ability to rebound and resist corrosion. The outer layers are embossed and coated on both sides with Viton (a flouroelastomer rubber based material that is heat resistant to 250 C/ 482 F). Viton is designed to meet the demands of a variety of harsh sealing environments, load conditions, and surface finishes. The center or shim layer is uncoated stainless steel, which can be varied to accommodate multiple thickness requirements.

Iskenderian rents a piston notching tool for enlarging the valve pockets in your pistons. Part number PNT-218 is 2.125" diameter and Isky's phone number is 310-217-9232. These operate by installing the tool in the valve guide with the heads located on the motor, so you know the notches are in the right place EXACTLY.

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Thanks for the reply you have a lot of useful information... Much appreciated I will get the mfgs ASAP