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Obtaining correct Quench

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Glasply21

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I have a desire to build a 350 chevy and bore it .030" over. (355 ci) This will be put in 21' Glasply cuddy cabin hard top. Appr wt #5000

My piston choice will be a D-dish piston that tries to match the combustion chamber shape.
My block is a Gen I (suppose to be a 1999) roller cam and is a Votec.

If I stay with the OEM Vortec head the rocker studs will be drilled and tapped plus the valve spring area enlarged.

When it comes to Quench there are plenty of possibilities on getting that .040". I would like to get opinions on whether to shave the deck to zero and use the new composite gasket of .039 or .040 versus shaving the deck to a given amount and using some type of shim gasket for the proper Quench.

Currently I only have access to a cast iron 2 bbl Rochester vortec manifold.

I was able to get Dennis Moores book from the library. That is a MUST READ for anybody interested in boat engines.

I am striving for a 9:1 compression ratio.

Any thoughts on the cam choice would be appreciated.

The cam specs I am looking at are: This is listed in Dennis Moores book.
Duration 208 intake
214 exhaust
Lift .438 intake with 1.50:1 rockers
.452 exhaust “ “
Lobe Centerline
108 degrees ATDC
112 degrees BTDC
Lobe Separation
112 degrees
Thanks for any input.
 
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Glasply21 said:
I have a desire to build a 350 chevy and bore it .030" over. (355 ci) This will be put in 21' Glasply cuddy cabin hard top. Appr wt #5000

My piston choice will be a D-dish piston that tries to match the combustion chamber shape.
My block is a Gen I (suppose to be a 1999) roller cam and is a Votec.

FYI....
The smaller pre-Vortec cylinder head chambers (64/65cc etc) will work best with the D-dish piston with the correct dish volume to control the SC/R.
If using the 76cc chambers, a single valve relief F/T piston can be made to work.
The Vortec cylinder head chambers will work best with a LCQ style piston with the correct dish volume to control the SC/R.

If I stay with the OEM Vortec head the rocker studs will be drilled and tapped plus the valve spring area enlarged.

When it comes to Quench there are plenty of possibilities on getting that .040". I would like to get opinions on whether to shave the deck to zero and use the new composite gasket of .039 or .040 versus shaving the deck to a given amount and using some type of shim gasket for the proper Quench.
Talk to your machinist and ask for his advice.

Currently I only have access to a cast iron 2 bbl Rochester vortec manifold.

I was able to get Dennis Moores book from the library. That is a MUST READ for anybody interested in boat engines.
Yes, Dennis Moore's knowledge of the SBC and of the Q/E is excellent.

I am striving for a 9:1 compression ratio.

Any thoughts on the cam choice would be appreciated.

The cam specs I am looking at are: This is listed in Dennis Moores book.
Duration 208 intake
214 exhaust
Lift .438 intake with 1.50:1 rockers
.452 exhaust “ “
Lobe Centerline
108 degrees ATDC
112 degrees BTDC
Lobe Separation
112 degrees
Thanks for any input.
Click to expand...
 
Talk to your machinist and ask for his advice.
Click to expand...

Ayuh,... Sound advice,....

I believe goin' zero deck, 'n the 12cc pistons puts ya right 'round 10:1,....
The 18cc pistons might be the ones ya want,....

Ya gotta do the math,...
 
Thanks Ricardo. It appears I could use more education. What exactly is the difference between D-dish and LCQ pistons. Other than the LCQ appears to have the same flat shape area as the vortec head both pistons have a dish area to work with on getting proper compression.
Thanks,
 
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