What crank is needed for 427 small block ?

[MotorHead]

Bought a 400 block last weekend and want to build a 427 stroker. What combination of crank( stroke 3.875 ?), rod pistons etc. will get me 427 cubic inches and 10:1 compression with a 64 cc head. Also how much clearancing is needed and where ? And do I need to go to a small base circle cam ? Any info and tips on building 427 small block would be appreciated. :D

[SmokedTires]

A stock bore (4.125) with a 4" stroke will get you 427.6 ci. A 4.155 w/ 4" stroke will get 433.9 (434ci). And 4.155 w/ 3.875 stroke = 420.3ci.

Did you get a 2 bolt or 4 bolt block?

When going to such large ci in a sbc, you want to be looking at some really big heads to get the flow needed for those ci's, start thinking in BB terms ;) .

[MotorHead]

I got a 2 bolt "817" casting block. I have Sportsman II heads ( 64 cc and 200cc runners ) that are going to be fully ported but I will probably put them on they way they are first.

Is there any way to get 427 cubic inches out of a 30 over ( 4.155 bore ) block ?

[Modified by MotorHead, 9:47 AM 1/24/2003]


[Modified by MotorHead, 10:31 AM 1/24/2003]

[CFI-EFI]

What's wrong with a 434? If you're in love with the "427" number, you could have a custom 3.9364" crank ground up for you, for a gazillion dollors. A standard bore block would probably be cheaper. Good luck, and...

RACE ON!!!

[MotorHead]

You guessed it, I like the sound of 427 small block :D

[DeenHylton]

I did some research a few weeks ago as I too was considering building a large SB...but just ended up ordering a new Turbo 5-spd PT Cruiser instead for my daily driver. I found you can run up to a 3.875 stroke crank without having to run a small-base dia. cam depending on which rods you choose. To get down to 10:1 compression ratio with your 64 cc head will require you to run an inverted dome piston (dished) because a flat top piston will yield more than 11.5 :1 with your heads. You'll also need to purchase a stroker style pan such as the Milodon #30908 ($210. from Jegs)...it will accept up to a 4" stroke. I know you'll need to do some grinding (notching) at the bottom of the block to get close to the notches built-in to your stroker pan. I'm no expert as I've never actually assembled one but I'm sure there are others on this board who have...Deen


[Modified by DeenHylton, 4:32 AM 1/25/2003]

[need-for-speed]

You guessed it, I like the sound of 427 small block :D

hell, just build the 434 and lie, nobody will know that it's not a 427, except us, and we won't tell, trust us :D


[Modified by need-for-speed, 1:01 PM 1/25/2003]

[CORKVETTE1]

I did some research a few weeks ago as I too was considering building a large SB...but just ended up ordering a new Turbo 5-spd PT Cruiser instead for my daily driver. I found you can run up to a 3.875 stroke crank without having to run a small-base dia. cam depending on which rods you choose. To get down to 10:1 compression ratio with your 64 cc head will require you to run an inverted dome piston (dished) because a flat top piston will yield more than 11.5 :1 with your heads. You'll also need to purchase a stroker style pan such as the Milodon #30908 ($210. from Jegs)...it will accept up to a 4" stroke. I know you'll need to do some grinding (notching) at the bottom of the block to get close to the notches built-in to your stroker pan. I'm no expert as I've never actually assembled one but I'm sure there are others on this board who have...Deen


[Modified by DeenHylton, 4:32 AM 1/25/2003]

a 3.875 will hit the cam on a non small base circle even with stroker rods even a 3.75 will probally hit on a stock cam over 500 lift with stroker rods we just mocked up skis with stroker rods and 3.75 stroke it was not hiting but only 15 thousand clearance need less to say we opened that up some :cheers:

[danno85]

If you have a good enough block to go .060 over with it, then
a 4.185 bore and 3.875 stroke crank will net 427 cu inches.

Make sure you enlarge the combustion chambers around the intake
valve to match the bore size. That will unshroud the valves and let it
breath better and the extra CCs won't hurt you any - your gonna
have problems with getting the compression ratio down to where you
want it anyway.

Dan

[dsagers]

Since you are going to be grinding on the bottom of the block, just for safety and block stability, consider filling the block with block cement, but just up an inch or half inch below the water pump holes. This way you reduce the risk of grinding into a water jacket and runing a block.

Ma sure you fill the block before boring and any other machine work.

[MotorHead]

Thanks for all the help and info. I do believe I like the idea of building either a
420 ci or a 434 ci and lying :lolg:

[tpi 421 vette]

I think you will like the power of a big small block. A 420 might be a little easier to build, less clearancing and you can use a stock pan if you choose. That 4"stroke really pushes things to the limit with a standard deck height.