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View Full Version : What is a 350 bored 0.40 over?


CHEVYDADDY
10-28-2008, 03:00 PM
a motor yeah i got ya there! wht would it equal or close to what?
i have a short block together needs some cleaning and have heads together need some cleaning wht should i use to clan and how should i go about doing it? wire brush our spary gunk and wip off or even water??

Duntz00
10-28-2008, 04:47 PM
358 is a .40 over 350

shaun89
10-28-2008, 08:28 PM
ya, just some engine degreaser/kerosene/diesel would work good with a wire brush and lots of scrubbing,i would somehow tape or block off the cylinders to keep and the flying crap out of them.

Stomis
10-28-2008, 08:30 PM
358 is a .40 over 350

I always thought it was a 357?

80' 427
10-28-2008, 08:34 PM
actually .40 is 423.316
.040 is 356.880

38377k5
10-28-2008, 08:36 PM
(4.040in/2)^2 * 3.14 = 12.819 in^2

12.819*3.48 = 44.610 in^3

44.610 in^3 * 8 cylinders = 356.88 in^3

4X4HIGH
10-28-2008, 08:39 PM
Bore x Bore x Storke x .7854 x number of cylinders = CI. 350 .040" over is a 356.88 or 357. :D

CHEVYDADDY
10-29-2008, 12:04 AM
what is suggestable horse power for 357?
can a 350 motor be borad to a 400? how much would it take?

buffblazer
10-29-2008, 12:43 AM
for horsepower its gonna all depend on your set up.

what heads
cam
roller or hydro lifters
inkake
carb
serp set up or stock
any emissions
headers

lots of stuff play into how much horsepower your gonna make with a .40 motor

mine is .40 with flat top pistons, stock heads with hydro lifters, comp cams extream 4x4 cam, performer intake and 600cfm edlebrock carb with headers and a regular v belt set up with no emissions. is that similar to what your gonna be running?

CHEVYDADDY
10-29-2008, 12:47 AM
for horsepower its gonna all depend on your set up.

what heads
cam
roller or hydro lifters
inkake
carb
serp set up or stock
any emissions
headers

lots of stuff play into how much horsepower your gonna make with a .40 motor

mine is .40 with flat top pistons, stock heads with hydro lifters, comp cams extream 4x4 cam, performer intake and 600cfm edlebrock carb with headers and a regular v belt set up with no emissions. is that similar to what your gonna be running?
yes i traded ariding lawn mower for a short block all together and matching heads i have to clean both but not sure on all details sounds goods

4X4HIGH
10-29-2008, 12:48 AM
what is suggestable horse power for 357?
can a 350 motor be borad to a 400? how much would it take?

Power is made in the head and cam selection. Most 350's stock put out around 180-210hp.

No, you cannot bore a 350 block out to make a 400. A 400 bore is 4.125".

CHEVYDADDY
10-29-2008, 12:50 AM
headers
no emissions
600 cfm
v-belt
heads 626862 (didnt write it down)
block and heads go together

CHEVYDADDY
10-29-2008, 12:55 AM
[quote=

No, you cannot bore a 350 block out to make a 400. A 400 bore is 4.125".[/quote]

ok i had a 78 3/4 ton longbed chevy 350 "said to be 400" no proof with 4 speed and 4:10 gears with 40"mudders 17"wide each and the truck would hual A** of course bulldog but first and second had alot of power. 4th did ok say possible 383stroker?

rob h
10-29-2008, 04:44 AM
i took a 74 350 and had it bored .040, decked, maged, line honed, i bought a crane 535 lift cam, comp 1.6 thought 1.7 but no 1.6 roller rockers, domed keithblack pistons 12:1, eagle crank and rods, and bowtie heads with 2.055 stainless valves, comp springs,titanium retainers. melling oil pump, elelbrock rpm airgap intake, holley 750 dp jetted down , holley red fuel pump, all arp bolts, summit 7 qt pan, mallory unilite dist, taylor wires, 1 5/8 primary tubes on headman headers, 3inch ball flanges and 3inch all the way out the back....and ill tell ya its an animal behind my 465 with 456 gears..i have no idea the horsepower range but with 37s i can go 30 and stand on it and burn em off in 3rd gear..

Wasatch K5
10-30-2008, 06:34 AM
I think the 400 blocks from the factory did not have cooling passages between the cylinders and that's why they could be bored to 4.125.

If you tried that with a 350 block the cylinder wall thickness would be too thin after boring.

jt512
10-30-2008, 06:56 AM
400's also had a longer stroke crankshaft which adds ci's

6.2Blazer
10-30-2008, 10:38 AM
First of all, it's 0.040" overbore, or "40-thousands" of an inch not 0.40" (almost 1/2 inch).

A .040" overbore motor will make the same power as a .030" overbore motor, an .060" overbore motor, or a one with no overbore, assuming everything else is equal.....any power difference between them is more likely because of a difference in tolerances of other components. Doing an overbore on an engine is not a performance modification, it's simply done to clean up the cylinders from years of wear and tear when you rebuild it. It's kind of like turning down a brake rotor, you do it because it gives you a nice smooth surface again not because it makes it work better than a new un-turned rotor.

Sorry for the slight rant, but this is just one of my pet-peeves.

jt512
10-30-2008, 11:34 AM
rant away man, i hear you:D . I used to run a motorcycle shop and it would drive me nuts when people would come in asking about how much it would cost to put a "powerband" in their bike. Generally it was people that owned older 4-strokes and had just ridden a 2-stroke for the first time:confused:. trying to explain exactly what a "powerband " was and the difference between a 2-stroke and a 4 was enough to drive you nuts!

oh, i think the correct answer to "what is a 0.40 over 350?" ........scrap!:D

4xcrazy
10-30-2008, 06:57 PM
got any of those "powerbands" for my .030 overbored 350? :D

4X4HIGH
10-30-2008, 08:36 PM
400's also had a longer stroke crankshaft which adds ci's


The 400 block is a complete different casting all together as it also has larger main bores than any other SBC ever made.

79rustyk10
10-30-2008, 09:21 PM
The 400 block has siamiese bores, so there is no space for coolant to flow between cylinders, this is why they have the extra "steam holes" in the deck and in the cylinder heads. No other small blocks had these as the water jacket seperates the cylinders. The siamese bores in the 400 were required because GM wanted to keep the same bore centers as the other SBC engines for interchangability of other components. Just think if Ford had the ability to think like that, they would have what, 3 less different engine families, 2 less bellhousings and god knows what else.