Author Topic: 401/425 crankshaft ?  (Read 4366 times)

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Offline 35chevcoupe

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401/425 crankshaft ?
« on: April 03, 2015, 11:35:58 PM »
Does anyone know if there is a company out there that makes new billet cranks for the 401 or 425 Nailheads ?
John Evenson

1930 model A 4 dr sedan
35 chev coupe 2 dr Master Deluxe suicide dr,s
55 chev belair wagon 4dr
59 Buick Invicta 2 dr hd top
65 Buick GS 2 dr ht
71 Buick GS
84 chev 3/4 ton p/u 6.2 diesel
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Offline WkillGS

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Re: 401/425 crankshaft ?
« Reply #1 on: April 04, 2015, 08:42:08 AM »
Highly unlikely.
The originals are forged. It's a good piece, would be expensive to reproduce.
Walt K
Eastern Pa

66 GS Astro Blue/blue 425 auto
66 GS Silver Mist/black 401 4 spd
66 GS Flame Red/black 401 5 spd
66 GS Saddle Mist/black 401 L76 auto
66 Special Flame Red/black 300 5 spd
65 GS vert Verde Green/ Saddle buckets 401 4 spd
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Offline 35chevcoupe

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Re: 401/425 crankshaft ?
« Reply #2 on: April 04, 2015, 07:27:09 PM »
Thanks Walt . 
I,m planning on building a 425 with a blower for one of my cars and want to make sure the bottom end can handle it .
nothing too wild though so maybe the stock crank will be ok .
John Evenson

1930 model A 4 dr sedan
35 chev coupe 2 dr Master Deluxe suicide dr,s
55 chev belair wagon 4dr
59 Buick Invicta 2 dr hd top
65 Buick GS 2 dr ht
71 Buick GS
84 chev 3/4 ton p/u 6.2 diesel
Yeah there's more
There all projects

Offline Loren At 65GS

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Re: 401/425 crankshaft ?
« Reply #3 on: April 04, 2015, 10:13:25 PM »
A blower.... interesting.  You may want to talk to Carmen.

  Loren
65 GS htp BCA Senior
 65 Skylark coupe/2x4BBnailhead
 65 Skylark coupe v-6
 65 GS htp project
 70 GS 455 htp / original engine
 94 Roadmaster wagon
BCA 14371

Offline Dr Frankenbuick

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Re: 401/425 crankshaft ?
« Reply #4 on: April 05, 2015, 06:56:25 AM »
I'd be more concerned about the main saddles and two bolt mains. The crank and rods are ready for some abuse.


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Offline Loren At 65GS

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Re: 401/425 crankshaft ?
« Reply #5 on: April 05, 2015, 09:28:58 AM »
At risk of being redundant, Carmen may be a good source of information.  He use to race a nailhead "back in the day".

  Loren
65 GS htp BCA Senior
 65 Skylark coupe/2x4BBnailhead
 65 Skylark coupe v-6
 65 GS htp project
 70 GS 455 htp / original engine
 94 Roadmaster wagon
BCA 14371

Offline 35chevcoupe

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Re: 401/425 crankshaft ?
« Reply #6 on: April 05, 2015, 09:00:21 PM »
Loren , is Carmen on the 65GS site .  I'm not real familiar with everyone here yet but trying .
John Evenson

1930 model A 4 dr sedan
35 chev coupe 2 dr Master Deluxe suicide dr,s
55 chev belair wagon 4dr
59 Buick Invicta 2 dr hd top
65 Buick GS 2 dr ht
71 Buick GS
84 chev 3/4 ton p/u 6.2 diesel
Yeah there's more
There all projects

Offline 35chevcoupe

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Re: 401/425 crankshaft ?
« Reply #7 on: April 05, 2015, 09:10:56 PM »
Dr Frankenbuick ,    i agree with you on the mains as that usually is a big concern .  I am researching the 401 425 blocks to see if they will accept a custom set of splayed billet main caps .
usually if there is plenty of main webbing there the 2 bolt blocks work great .
I have a really good machine shop that might be able to make me a set . ( just depends how many Franklins i want to fork over )
John Evenson

1930 model A 4 dr sedan
35 chev coupe 2 dr Master Deluxe suicide dr,s
55 chev belair wagon 4dr
59 Buick Invicta 2 dr hd top
65 Buick GS 2 dr ht
71 Buick GS
84 chev 3/4 ton p/u 6.2 diesel
Yeah there's more
There all projects

Offline Loren At 65GS

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Re: 401/425 crankshaft ?
« Reply #8 on: April 06, 2015, 08:36:24 AM »
John,

Unfortunately, Carmen will not use a computer.

You can get ahold of him the old way. LOL

Carmen Faso at: 716-693-4090.  He is in North Tonawanda, NY.

  Loren
65 GS htp BCA Senior
 65 Skylark coupe/2x4BBnailhead
 65 Skylark coupe v-6
 65 GS htp project
 70 GS 455 htp / original engine
 94 Roadmaster wagon
BCA 14371

Offline 35chevcoupe

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Re: 401/425 crankshaft ?
« Reply #9 on: April 06, 2015, 09:37:55 PM »
Thanks Loren ,  Ill give him a call .
John Evenson

1930 model A 4 dr sedan
35 chev coupe 2 dr Master Deluxe suicide dr,s
55 chev belair wagon 4dr
59 Buick Invicta 2 dr hd top
65 Buick GS 2 dr ht
71 Buick GS
84 chev 3/4 ton p/u 6.2 diesel
Yeah there's more
There all projects

Offline telriv

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Re: 401/425 crankshaft ?
« Reply #10 on: May 14, 2015, 07:41:25 AM »
John, the blocks are pretty sturdy as they are. At one time I sent caps to Milidon to see about making caps for a 401 we were building. They said the caps were of GOOD quality with a lot of Nickel content & would be strong enough for ANY normal performance work. A small boost or 200-250 HP shot of nitrous. The ONLY thing I caution about is the stability of the cyl. walls. Because of the weight of the reciprocating assembly the walls need to be AT LEAST .150" thick minimum by calculations. Some aren't even that thick from the factory. So the block needs to be SONIC tested. You need a basis from where your starting. You wouldn't build a new house on an old crumbling foundation. Even on stock rebuilds I add epoxy filler to the bottom of the BIG freeze plugs on the side of the block just to stabilize the bottom of the bores. The left side of the block holds less than the other. aprox. 16 ozs. The right approx. 32 ozs. So use the same amount on both sides.This filler DOES NOT affect oil temps or coolant temps. as I & others I've told to do this have experienced. In fact they seem to run cooler. Only way I or Dennis Manner can explain it is that more coolant is running around the top of the block where it's actually needed more than the bottom for cooling of the oil. This is using temp gauges for both. I would guess that in a pressurized situation that the top needs more cooling than the bottom since your increasing air/fuel intake & increasing the heat from the extra air/fuel.
On one of our engines we were having MAJOR cyl. leak down problems. Pull the engine, rough up the walls & install new rings. After doing this 3-4 times, after 15-20 runs down the 1/4, I didn't really want to be involved anymore until we got the block sonic tested. Found that the 3 worst cyl. walls were only .090" thick on one side & .300" thick on the other. Since this was only bored .030, meaning only .015" was removed from the cyl. wall, the original thickness was ONLY .105" thick new!!! After adding the epoxy ALL those problems ended. Other problems cropped up unrelated to the epoxy.  Talk about core shift!!! As I was told,  "during the casting process that ANY blocks that came down the line with centered bores were taken OFF the line & sent to the racers".
 By pressuring the intakes you now have a problem with the exhaust GETTING OUT. But the boost we put a SMILE on your face.
Good luck & have fun which is what this is ALL supposed to be about.


Tom T.


Classic & Muscle Automotive
C/O Tom Telesco
12 Cook St.
Norwalk, Ct. 06853-1601
Daytime phone:
203-324-6045
No answer: leave message, will call back
E-Mail: telriv@yahoo.com

Offline 35chevcoupe

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Re: 401/425 crankshaft ?
« Reply #11 on: May 14, 2015, 09:48:33 AM »
Tom ,    thanks for the information .
I just picked up my 1st block ( thanks to Bill from this site ) a 425 which I have been studying quite a bit .
What I,m wondering and maybe you know , does  the 401 block have thicker cyl walls than the 425 ? 
I going to pick up a few more of these engines and take the blocks to a guy that builds my race engines for my dirt modified , He has a sonic tester to check wall thickness .
I,m not going very wild on the boost on this engine it will mostly be for looks and the additional music from the blower belt .
I,ve always wanted a car with a blower and I,m really thinking this car will look great with one .
When I talked to Carmen ( which was,t long ) he made it sound like head gaskets sealing was one of the main concerns . So when I get closer to doing the build I will be contacting him again .
Appreciate all info. I can get from you guys .
John Evenson

1930 model A 4 dr sedan
35 chev coupe 2 dr Master Deluxe suicide dr,s
55 chev belair wagon 4dr
59 Buick Invicta 2 dr hd top
65 Buick GS 2 dr ht
71 Buick GS
84 chev 3/4 ton p/u 6.2 diesel
Yeah there's more
There all projects

Offline telriv

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Re: 401/425 crankshaft ?
« Reply #12 on: May 14, 2015, 03:21:17 PM »
John, the stock head gaskets are good for about 13.5-1. So with a blower you will be starting out at NO MORE than 9-1 even with a small boost of 4-5 pds. which it will raise it to the 12.5-13.5 range as a guess.  Just use Hypolar (spelling) sealant. ALL 401/425 blocks NEED to be sonic tested. A casting number that ends in "705" could have been used as either a 401 or a 425. It all depended on core shift. It's only recommended in the shop/chassis manual to ONLY over bore a 425 .010". This is because of CORE SHIFT. Sure pistons are available in .060" over, but ring availability is usually a problem. There is a gap in ring availability from 4.340-4.350. Meaning if you bore the block .040" over (pistons available in this size) most likely you will get rings that are ONLY .030" over. Since most/many don't check ring end gaps, assuming all is OK, the gaps will be larger than recommended. Also because of the flexibility of the lower end WITHOUT filler the rebuild usually won't last as long because the rings get beat because of the bottom end flexibility/movement.  Then the walls will flex enough that it keeps wiping out the mains because of the flexibility of the lower end of the block. Depending on sonic test results I will ONLY go to a 4.350" bore will block filler. Many machinists believe that going .030" over is NO PROBLEM!!!! NOT ON A "Nail".
I could talk/type this info for days & not cover EVERYTHING. My typing ability's leave ALOT to be desired.
Carmen is a GREAT guy but falls short of some of the more modern things about "Nails". He stopped messing with them years ago & started selling parts ONLY. He won't even take on engine rebuilds any longer. This is in NO WAY anything bad about Carmen. As I said "HE'S A GREAT GUY!!!!
Just my thoughts on the subject at hand.


Tom T.


Classic & Muscle Automotive
C/O Tom Telesco
12 Cook St.
Norwalk, Ct. 06853-1601
Daytime phone:
203-324-6045
No answer: leave message, will call back
E-Mail: telriv@yahoo.com

Offline 35chevcoupe

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Re: 401/425 crankshaft ?
« Reply #13 on: May 14, 2015, 04:30:01 PM »
Yeah Tom , I realize we can't cover everything over the key board , but every little piece of advice helps .
When you mention block filler do you mean like  ( Hard block ) or an equivalent ?  Thats what we used to use on the old 400 sbc blocks .
I do know that there are some very good head gaskets out there also . The ones we use in our race engines are like 125.00 each because the space between the cylinders is so thin .
I,ll make sure to check the casting number when I,m looking at these blocks .
Thanks .
John Evenson

1930 model A 4 dr sedan
35 chev coupe 2 dr Master Deluxe suicide dr,s
55 chev belair wagon 4dr
59 Buick Invicta 2 dr hd top
65 Buick GS 2 dr ht
71 Buick GS
84 chev 3/4 ton p/u 6.2 diesel
Yeah there's more
There all projects

Offline telriv

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Re: 401/425 crankshaft ?
« Reply #14 on: May 14, 2015, 05:29:06 PM »
NO head gaskets available for a "Nail" other than the stock shim steel, which are getting more costly as time marches on, or the composites which I believe won't handle more than 11 or 12-1.
As far as filler. I use an epoxy that is used as a backing material for rock crushing equipment. What I like about it is that it has expansion & contraction rates much closer to cast iron than the standard "Hard Bloc". It's self leveling, the block doesn't have to be vibrates to get the bubbles out, is not porous like "Hard Bloc", won't break apart from vibration as "Hard Bloc" does & other things that escape my mind at the moment. When using ANY filler I want access to the block drains. What I do is use a piece of Styrofoam & cut it into a "VEE"shape. Thick enough for the block to hold it in place. Pour in your filler of choice. After the filler hardens just use carb. cleaner & the Styrofoam will be broken down/melted out. Now you have block drains again so the block can be drained.


Tom T.


Classic & Muscle Automotive
C/O Tom Telesco
12 Cook St.
Norwalk, Ct. 06853-1601
Daytime phone:
203-324-6045
No answer: leave message, will call back
E-Mail: telriv@yahoo.com