Decking questions
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From: Hayward Wi
Decking questions
dose any one here know what the max that can be taken off of an SBC 305 for decking?
also whats the max safe that could be taken off of GM882 heads and what would be an approximate CC amount after decking say .010 or .020 off them?
thanks
Ryan
also whats the max safe that could be taken off of GM882 heads and what would be an approximate CC amount after decking say .010 or .020 off them?
thanks
Ryan
Safety Car
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From: North Easton Mass
Rick B.
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From: Eastern Shore Virginia
Is the purpose of this exercise to raise compression? If so, you should consider a different set of heads. Otherwise you are looking at possible clearance, alignment, and quench issues, depending on your piston/rod combination/other factors. Or go with a larger bore block with those heads. 350 blocks are so easy to get, and like 72LS1 said, you machine the numbers off and originality is out the window anyway.
Burning Brakes
Joined: Jan 2007
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From: Concord Calif
Depends on the block if you need to deck it, such as the deck is not flat enough to hold a gasket. Then depends on a hot rod motor or just a stock type. Hot rod engines you would deck a motor to get the decks square to he crankshaft center line and then again to achive the desiered deck clearance to the pistons that you normally would not do for a stock engine.
Safety Car
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From: San Antonio TX
For milling the heads, you'd lose a bit under 2cc with a .010 cut. While there's a practical limit on how much you can or would deck a block, you have to work within the overall engine design. You could chop .20 off the deck without compromising the block, but that's not very useful if it leaves the piston is poking .18 out of the block. You deck the block to make it flat, square, and to suit a specific compression height to achieve a specific piston to deck clearance.
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From: Hayward Wi
For milling the heads, you'd lose a bit under 2cc with a .010 cut. While there's a practical limit on how much you can or would deck a block, you have to work within the overall engine design. You could chop .20 off the deck without compromising the block, but that's not very useful if it leaves the piston is poking .18 out of the block. You deck the block to make it flat, square, and to suit a specific compression height to achieve a specific piston to deck clearance.
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From: Eastern Shore Virginia
If you are not familiar with engine building techniques and time is not a critical factor I would recommend two things:
--pick up a couple of books on the subject (basics)---I like ones by David Vizard because he gives the reader the reasons for what he is recommending to do and usually takes cost issues into consideration
--get referrals for machine shops that do more than just standard rebuild stuff, and go talk with them about what it is you want to do (better to read up first so you can understand what they are telling you!) As a rule, the good ones don't work cheap.
--pick up a couple of books on the subject (basics)---I like ones by David Vizard because he gives the reader the reasons for what he is recommending to do and usually takes cost issues into consideration
--get referrals for machine shops that do more than just standard rebuild stuff, and go talk with them about what it is you want to do (better to read up first so you can understand what they are telling you!) As a rule, the good ones don't work cheap.
Le Mans Master
Joined: Apr 2006
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as far as the head goes about .010 after that you could have problems with intake manifold alignment. I don't know what the bore stroke demension is on the 305 but if you have 76 cc heads can't replace them you might could find a cheap small dome piston to raise your compression. On your other thread you list an 800 cfm carb for parts, with a hydrauilic low rpm 305 you need to look at 600/650 carbs.
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From: Hayward Wi
as far as the head goes about .010 after that you could have problems with intake manifold alignment. I don't know what the bore stroke demension is on the 305 but if you have 76 cc heads can't replace them you might could find a cheap small dome piston to raise your compression. On your other thread you list an 800 cfm carb for parts, with a hydrauilic low rpm 305 you need to look at 600/650 carbs.
i will have to look for domed pistons to. this is kinda my looking getting my crap together then doing the project with all my ducks in an row
Le Mans Master
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yah i will have to do some looking but i do hope to have an Q-jet so it can get the aprox CFM that i need so if it dose suck 750 CFM at 5500 RPM it can do so. but yet if it wants to at cruse it can suck like maybe 200 CFM.
i will have to look for domed pistons to. this is kinda my looking getting my crap together then doing the project with all my ducks in an row
i will have to look for domed pistons to. this is kinda my looking getting my crap together then doing the project with all my ducks in an row
a 3.250 ( 327 stroke ) and a 283 chevy bore size.
A 305 at 5500 rpm won't even come close to using 750 cfm so if you decide on a square bore carb look for a 600 / 650.
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From: Hayward Wi
what is the bore size on the 305 ? it may be a real odd size bore with no dome pistons made for it. The old 307 engine was made up by using
a 3.250 ( 327 stroke ) and a 283 chevy bore size.
A 305 at 5500 rpm won't even come close to using 750 cfm so if you decide on a square bore carb look for a 600 / 650.
a 3.250 ( 327 stroke ) and a 283 chevy bore size.
A 305 at 5500 rpm won't even come close to using 750 cfm so if you decide on a square bore carb look for a 600 / 650.
its got all the same piston heights as an 350 is more or less and under bored 350.
oh and supposedly there is a 263 that uses an 305 block and a 3.00 inch stroke (from the GEN II SBCs)
what is the pistion down bore for an 305 if it uses 350 numbers i have been using .030??
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From: Hayward Wi
yah your probably right there. i mean if i could get .060 pistons in FT i would be happy yah i think i am going to deck both the block and heads so i dont have gasket problems because im going with .028 gaskets.
