SoCal Jet Boats

Tech Talk => Engine Mechanical / Electrical => Topic started by: lupo1904 on February 05, 2011, 08:40:57 PM

Title: boring out
Post by: lupo1904 on February 05, 2011, 08:40:57 PM
how many times can a 454 be punched out and wut would it end up being?
Title: Re: boring out
Post by: obnoxious001 on February 05, 2011, 10:15:00 PM
Some of the early blocks are supposed to be able to go to 4.375", which is .125" over stock.  The largest I have run is 4.350" in a truck block with the 4.250" crank it was 505 cubic inches.  I ran first an 8-71 blower on it, and later a Gentry turbo setup, up to 15 lbs boost, perhaps 1000 HP with no block issues.

To be safe, the block should be sonic checked for cylinder wall thickness I would think.  It's very common to go to .060" over stock (4.310").  Can't tell you exactly how many bores since there are some weird piston sizes made, maybe .020" ,  .040" and .070" , besides the "normal" .030" and .060", and then as I mentioned even .100 and .125" over
Title: Re: boring out
Post by: enginedoctor on February 05, 2011, 10:47:09 PM
I would like to see many other comments on this thread....GT..care to add.??...
Title: Re: boring out
Post by: Nordie on February 06, 2011, 07:52:27 AM
When my block was sonic checked it was like .105...good thing im at .070
Title: Re: boring out
Post by: povertyjet on February 06, 2011, 08:41:31 AM
To be safe, the block should be sonic checked for cylinder wall thickness I would think.  It's very common to go to .060" over stock (4.310").  Can't tell you exactly how many bores since there are some weird piston sizes made, maybe .020" ,  .040" and .070" , besides the "normal" .030" and .060", and then as I mentioned even .100 and .125" over

I agree.  I would sonic check anything over .060 for Mk4 blocks, especially for boosted applications.  Gen V (1990?) & VI (1996?) block's cylinders are siamesed, so I believe they will take the bigger bores.
Title: Re: boring out
Post by: lupo1904 on February 06, 2011, 09:54:06 AM
ok guys thanks for posting,so the boat im gunna buy has a 468 in it would that be .30 over or .60 over?
Title: Re: boring out
Post by: OC2Vegas on February 06, 2011, 09:57:22 AM
ok guys thanks for posting,so the boat im gunna buy has a 468 in it would that be .30 over or .60 over?

461 - .30

468 - .60
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