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351 C to 408 Stroker

February 17 2003 at 12:43 AM
Cnefmikey  (no login)
from IP address 12.230.26.109

HI, I am looking some possible combinations for a 351 C into a 408 stroker. I have a 400 crank with the mains cut to cleveland standard and rod journals .010 undercut windsor. Does anybody know where I can obtain some info on this buildup? I am going to have the block pushed .030 over, it is standard bore at the moment with 125,000 on it. Thanks in advance, Mike

 
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glen
(no login)
65.176.177.97

strokin it?

February 17 2003, 3:06 AM 

i've been trying to figure this out for while myself. don't want a W crank snout to deal with. just Emailed a crankgrinder in IN as to what is possible as far as offsetting a 4m casting(stock C crank), or fitting a 5m casting(400cu in 4" stroke)and getting it to balance? plenty of info in the search on this site but seems to be a void of info on 335 series cranks. looking at kb235,chev ft,no reliefs,1.261 ch and kb285,clev eyebrow,1.44 ch. je has a piston also, clev eyebrow,1.25 ch...??????

 
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Russ
(no login)
65.166.222.29

Re: 351 C to 408 Stroker

February 17 2003, 11:04 AM 

Call your local machine shop that has an old ford guy to really help you with this.
ford motorsport makes a spacer for the svo crank to fit thier widsor type crank to a 351 cleveland.
part# M-19009-A341

 
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Brian S
(no login)
152.163.201.176

Re: 351 C to 408 Stroker

February 17 2003, 11:24 AM 

It's not a common build because of the short custom piston height. What rods were you considering?

Have you looked at the kit by speedomotive? http://www.speedomotive.com/351c_to_408_stroker_crank_kit.htm

 
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glen
(no login)
65.178.168.63

rod choice?

February 17 2003, 1:27 PM 

the way it looks to me , i need to find out max possible stroke w/ what crank? then rod choice is depending on rod journal size after offset grinding, length give or take (pin dia can be offset honed/bushed), and piston compression hight(ch). all the while keeping in mind the rods must be long enough for the piston skirts to clear the counterweights not withstanding reasonable clearancing. will a 400 crank rotate in a clev block once the mains are turned down? how much bigger are the counterweights? will they hit the bottom of the bores? can the thrust surfaces be corrected to clev specs? yes i've seen the kits at flatlander and motivewhatever but i still don't like the snout adapter. i saw a post about the crank timing sprocket being a problem ? if it were only so simple,400 crank w/4"stroke=2"throw,use W rods @ 5.955",je's piston w/ch @ 1.25". add it up-2+5.955+1.25=9.205 leaving .001 deck clearance! glad that was easy, let's call it a day

 
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glen
(no login)
65.178.168.63

rod choice?

February 17 2003, 1:27 PM 

the way it looks to me , i need to find out max possible stroke w/ what crank? then rod choice is depending on rod journal size after offset grinding, length give or take (pin dia can be offset honed/bushed), and piston compression hight(ch). all the while keeping in mind the rods must be long enough for the piston skirts to clear the counterweights not withstanding reasonable clearancing. will a 400 crank rotate in a clev block once the mains are turned down? how much bigger are the counterweights? will they hit the bottom of the bores? can the thrust surfaces be corrected to clev specs? yes i've seen the kits at flatlander and motivewhatever but i still don't like the snout adapter. i saw a post about the crank timing sprocket being a problem ? if it were only so simple,400 crank w/4"stroke=2"throw,use W rods @ 5.955",je's piston w/ch @ 1.25". add it up-2+5.955+1.25=9.205 leaving .001 deck clearance! glad that was easy, let's call it a day

 
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Chris Kelly
(no login)
64.216.57.67

AFAIK

February 17 2003, 1:37 PM 

you have to cut the heck out of the 400 counterweights. 4" stroke is a bit much for a 9.2 deck block, IMHO. And it can not really be done on the cheap. By the time you grind up the 400 crank, buy custom pistons and pop for balancing the whole mess, you could just build a 393 from off the shelf parts and put the rest of the $$ in your pocket. JE sells a piston for this setup - $600 with the rings.

 
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glen
(no login)
65.178.168.63

chris, do you know what's involved?

February 17 2003, 1:50 PM 

in using the SCAT W crank in regards to the snout? i just got a gear drive and they seam to be concerned w/the integrity of this area. no alum hub balancer, etc.. and what about the crank dia in regards to timing set compatability? so what do you know?

 
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Chris Kelly
(no login)
64.216.57.67

Not anything there

February 17 2003, 9:07 PM 

I read a lot of posts where people have used the Scat parts. If the same Summit balancer fits 289-400, then the snout diameter should be the same, it's then just finding if you need a spacer. I'd ask Scat what they're hearing and then hunt someone that's done it, but I'd bet you could find out what you need by dry fitting the crank in the block with the timing cover and balancer. I just know that Mallory metal is big bucks and starting with a crank that's made more for the application could put you money ahead. A friend balanced a SBC and the guy brought him a CAT crank from a swap meet. The dude like to fainted when he got the $400 bill for balancing the POS crank.

 
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glen
(Login grclark351)
63.183.104.41

the unbalanceable

February 17 2003, 10:21 PM 

one of the contributors here has a site(stroker guru)i read a while back about this same thing, maybe into a 302 block. he said the same thing, that it took all the kings horses to make it balanced again.called CHP today, tech guy said the crank sprocket just needs to be spaced a little farther out. we didn't get into specifics, how much i wonder? that spacer seems to be getting pretty popular,anybody got any details?

 
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futurattraction
(Login futurattraction)
Member
216.137.74.157

I can't speak for the 4" crank, but...

February 17 2003, 10:37 PM 

I'm collecting parts for a 3.85 stroke motor I'm planning to put together. You can get Scat cranks that already have the 2.75 Cleveland main with either 2.311 or 2.1 rod journals. Since I don't have all the parts yet, and haven't trial fitted anything yet, I can only say that everything I've read points to the need for a spacer on the snout of the crank to make up for the lack of the stepped, machined surface that the sprocket seats against. I've got the sprocket, but haven't got any pictures of it at this point.
Scott

 
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glen
(Login grclark351)
63.183.104.41

thrust bearing journal length

February 17 2003, 11:04 PM 

in the ford 1972 car shop manual, volume II engine-we find 1.124-1.126 for clevo,1.137-1.139 for W. a difference of .013 ah-hah

 
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futurattraction
(Login futurattraction)
Member
216.137.74.232

Pics of Scat crank snout and spacer in Photos section

February 18 2003, 7:26 PM 

n/m

 
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Chefmikey
(no login)
12.230.26.109

351 to 408 stroker update!!!!

February 18 2003, 3:33 AM 

Thanks for all the info to date!! The 400 (4")crank that I am wanting is use is cut to cleveland mains (2.75). I dropped the 400 crank into the 351 c block and noticed what everybody has said and is correct. Max clearance from the bottom of the bore to the counterwights is .035 at best. Rods are going to have to be 6.00 with journals 2.311.Crank will spin freely but have to watch the clearances on this close. I will have to use the snout adapter everybody is talking about it, even though I dont like the sounds of it. Pistons? I have had some input, but the skirt has to be short. I am going to assemble a website showing detailed photos for the next guy that wants to take the challenge on. I am going to get a plan together this week and present it, and see what everybody thinks.Please keep the info comming, this is the best thread I have found for 351 C and wish I would have found it sooner. Here is my log cabin im bulding at present if anybody is interested. Thanks Guys, http://www.jackassjunkshoppe.com/cabin.html

 
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Clive NZ
(no login)
203.97.2.243

For Rod have you considered the following.........

February 18 2003, 3:45 AM 

302C 6.028" nominal 2.311" big end, or 351W 5.95" nom. and 2.311" big end. Close as you get off the shelf.
Heads are going to be an issue for C.R as your piston will be quite short and will need a huge dish if you use closed chamber heads. Clevelands need the top ring quite low to clear the inlet valve notch so your oil ring often ends up across the gudgeon pin opening.
What about using a 351W block and cleveland heads for the extra deck height. You could have gone with a standard main size crank from 400?

 
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glen
(Login grclark351)
63.183.104.41

hey clive! take a look at

February 18 2003, 3:49 AM 

scat crank 9-351-400-6000-2100c on the flatlander site and tell me if there's any problem w/it?

 
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Chris
(no login)
210.54.247.221

Stroker articles

February 18 2003, 5:53 AM 

I have two articles on early stroker 408 windsors using the 400 Cleveland crank. The rods they used were anything from 400 Cleveland rods to 300ci 6 pot Ford rods as well as 360 mopar. It seems the biggest problem is that once the counterweights are cut (ground) down, there are big problems getting weight back into the crank to balance the thing. They were using slugs of moly in the counterweights. The counterweights were ground to 1.900" as measured from the main bearing surface i.e 4.90" from the crank centerline. This brings us to the next problem...with the rods they were using, they only had 0.060" clearance between the CW and the bottom of the piston...even the base of pin area of the piston was radiused to give clearance. The 6" rod may sound fine but you've gotta have room between the cw and the piston whilst leaving some meat in the piston boss itself for structual integrity. These guys had stroked that one alittle but its something to keep in mind. I considered this afew years back and obtained a 5MA crank....in WON'T rotate in a 351C block without cutting the cw's, you've got clearance for the rods without any relieve cutting in the block or bores (was going to use the aussie 302 6" rods) but no lower piston or block clearance.

 
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Mark McKeown
(Login manyponies)
Member
66.44.102.157

Re: 351 C to 408 Stroker

February 18 2003, 12:59 PM 

I have put together all of the pieces to do these. It requires machining an aftermarket 4340 crank. The rods are 4340 h beams and custom pistons. The crank, rods, piston,rings,bearings, wrist pins and balancing is 2375.00. It comes with all of the clearances set and balanced, ready to drop in, no hidden costs.
It fits a cleveland block, Most of these kits require an SVO block

Mark McKeown
McKeown Motorsport Engineering, Inc.
http://mmeracing.com

 
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Chris Kelly
(no login)
64.216.57.67

That's a good price for an out-the-door ready to go kit.

February 18 2003, 2:41 PM 

Especially with all the engineering done. I'm sure this kit costs more than a comparable 393 kit because if the extra hacking. The Q - are the extra 15 cubes worth the extra expense? Is there that much more power in the 408 in terms of dollars (all else remaining equal - which it almost never does)

 
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Mark McKeown
(Login manyponies)
Member
66.44.102.157

Re: That's a good price for an out-the-door ready to go kit.

February 19 2003, 7:11 AM 

Point # 1 Additional expense of 408 vs 393 . This is a apples to oranges comparison as the materials (crank,rods,pistons)in the 408 are far superior to that of the 393 kits on the market.
Point # 2 The increase in piston speed is worth the effort. By increasing piston speed you artificially rev the engine higher, increasing port velocity, which is what a large port engine wants in the first place.

Mark McKeown
McKeown Motorsport Engineering, Inc.
http://mmeracing.com

 
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