C4 Tech/Performance L98 Corvette and LT1 Corvette Technical Info, Internal Engine, External Engine

Max overbore for a 406CI , 509 casting ?

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Old Jun 10, 2006 | 08:38 PM
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Default Max overbore for a 406CI , 509 casting ?

OK, the fried pistons scratched one cylinder, @ .005 deep by @ .010" wide.

Can I go to 4.165" ?

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Old Jun 10, 2006 | 08:51 PM
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That wouldn't be my first choice, but obviously, it wasn't your's, either. You really ought to be OK at .040" over. A sonic test would remove any and all doubt.

RACE ON!!!
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Old Jun 10, 2006 | 09:18 PM
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We'll see what the engine guys say on Monday

It is closer to .015 wide and probabl y .005-.010 deep, it is hard to say for sure
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Old Jun 10, 2006 | 11:05 PM
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I have been at .040 over for a few years now without any issues. No gasket or heat problems even w/out steam holes in the heads.

If .010 will do it, and the block is otherwise in good shape, you should be OK.

Going back to MR???
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Old Jun 11, 2006 | 02:05 AM
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Originally Posted by RainDelay
I have been at .040 over for a few years now without any issues. No gasket or heat problems even w/out steam holes in the heads.

If .010 will do it, and the block is otherwise in good shape, you should be OK.

Going back to MR???
Awesome!

HSR
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Old Jun 11, 2006 | 02:34 AM
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Mine's at 4.169 with no problems...you need to have your machinist sonic check your block though, some of those 400's will have core shift.
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Old Jun 11, 2006 | 03:05 AM
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my 400 block is .040 over. I have aulm. heads with steam holes. 12.8 compression never a heat problem in 2 yrs. but I have the right parts to keep it cool.
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Old Jun 11, 2006 | 07:57 AM
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Schweet, I will pull the crank and cam today and drop it off. Eiither way, I have to strip it down.

I have never looked for 4.165 head gaskets, I hope they have them without costing an arm and a leg.

Gonna need a .039" with .005 in the hole.

Thanks guys!
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Old Jun 11, 2006 | 08:40 AM
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Originally Posted by LD85
Schweet, I will pull the crank and cam today and drop it off. Eiither way, I have to strip it down.

I have never looked for 4.165 head gaskets, I hope they have them without costing an arm and a leg.

Gonna need a .039" with .005 in the hole.

Thanks guys!
HSR, you sneaky feller!

I have been running off-the-shelf Fel-Pro gaskets 1014 or 1015 I think. I believe they actually measure out to a 4.190 hole. The ones I have been using have "marine" on them, I don't notice anyhting different from non marine so I don't know that it really matters in the end.

Good luck!
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Old Jun 11, 2006 | 12:36 PM
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Originally Posted by RainDelay
HSR, you sneaky feller!

I have been running off-the-shelf Fel-Pro gaskets 1014 or 1015 I think. I believe they actually measure out to a 4.190 hole. The ones I have been using have "marine" on them, I don't notice anyhting different from non marine so I don't know that it really matters in the end.

Good luck!
Awesome, this should be a painless rebuild, if there is such a thing.

Also, I need to revise my famous saying.

"whomever said third time is a charm,,, never did it 5 times"
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Old Jun 13, 2006 | 03:24 PM
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the 400 that i had in my z28 had a .060 over bore
that engine seen 8000 rpm many times
(thats with the monster tack)
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Old Jun 13, 2006 | 06:31 PM
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I dropped it off to have it

bored out to 4.165,
decked to .005 in the hole,
new pistons, crank, rod and cam bearings.
and have the crank polished,
and,,,, the AFR-210's are getting a port job,,, in search of 300-CFM or more at .600 lift

Gonna be topped off with a HSR, that will use the HSR plenum and it will still be removable wtih the stock HSR bolts, and still fit under a C4 hood.

Yeah baby , yeaaah!
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Old Jun 13, 2006 | 09:34 PM
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Originally Posted by LD85
I dropped it off to have it

bored out to 4.165,
decked to .005 in the hole,
new pistons, crank, rod and cam bearings.
and have the crank polished,
and,,,, the AFR-210's are getting a port job,,, in search of 300-CFM or more at .600 lift

Gonna be topped off with a HSR, that will use the HSR plenum and it will still be removable wtih the stock HSR bolts, and still fit under a C4 hood.

Yeah baby , yeaaah!
That sounds like a fun hot rod. Good luck to you and keep us posted.
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Old Jun 14, 2006 | 12:38 AM
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Originally Posted by LD85
Gonna be topped off with a HSR, that will use the HSR plenum and it
will still be removable with the stock HSR bolts, and still fit under a C4
hood.
For my part, I'd encourage you to start a thread on
this aspect of the project, if you are inclined to share.

I'm sure I'm not alone in being interested.

.
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Old Jun 14, 2006 | 02:38 AM
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Id liketo hear about it also.
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Old Jun 14, 2006 | 04:58 AM
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Originally Posted by Slalom4me
For my part, I'd encourage you to start a thread on
this aspect of the project, if you are inclined to share.

I'm sure I'm not alone in being interested.

.
I will take pics of the process, basically it will look like a reduced height factory HSR plenum, saving the top ribs for appearance.

I plan on putting the plenum on a Bridgeport mill and using a vertical collet type slitting saw to cut the bottom 1" (or what ever it takes, of of the bottom off of the plenum all the way around, and will machine the bolt hole support pillars flush with the bottom too.

Then I'll weld in a new piece of 5/16 or 3/8 thick 6061 aluminum in place of the cast piece that I cut out, this piece will have all of the intake and mounting holes machined into it before hand.

Then I will take another block of aluminum, put the mouting hoels in it and either bolt or weld it to the front of the plenum for the necessary throttle body down angle.

Then polish it up and bolt it on. I will still use the existing mounting holes and wont have to grind anything off of the intake runners.

FWIW, I wont receive the HSR until Monday or Tuesday since I bought it used from a guy in Texas and probably wont post pics for another 2-3weeks.

My engine is due back at the mid to end of next week and I plan on putting it back in before I start this mod and F1 weekend I will have friends coming into town from Cali and FLA.
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Old Jun 15, 2006 | 11:17 AM
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Originally Posted by LD85
Schweet, I will pull the crank and cam today and drop it off. Eiither way, I have to strip it down.

I have never looked for 4.165 head gaskets, I hope they have them without costing an arm and a leg.

Gonna need a .039" with .005 in the hole.

Thanks guys!
Flat out gaskets make a rubber coated copper one (www.flatoutgaskets.com):

pn. 917744165
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To Max overbore for a 406CI , 509 casting ?

Old Jun 15, 2006 | 04:07 PM
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Originally Posted by Blownfuel1
Flat out gaskets make a rubber coated copper one (www.flatoutgaskets.com):

pn. 917744165
I had the flatout. 027 thick on there last time, cost $150 for a set!

Gonna get the Marine Felpro .039, = $40
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Old Jun 30, 2006 | 04:27 PM
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UPDATE:

There was crack from a head bolt to a cylinder bore,

had to get another 400 block
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Old Jun 30, 2006 | 06:57 PM
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Well, THAT sucks. I hope you were lucky enough to find the crack before you ordered the pistons and rings.

RACE ON!!!
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