there was a tread about making a 348 a 408 using a 427 crank,,,anyone know hows its done and what rods pistons bore ect..........also need a relay from zanesville ohio to me or close to south jersay ,,,its a 348 block
you might want to join the 348-409.com message board, i know it has been discussed over there. Whats the 348 goin into? http://www.348-409.com/forum/forumdisplay.php?f=9
One of the magazines has an article this month about a big inch W-motor. OK, found it in Feb 08 Car Craft.
In the early 80's that was a popular trick for Pro Stock drag racers to de-stroke their Big Blocks using 409 crankshafts. To go the other way using a 396/427 crank or even a 454 crank in a 348/409, the mains will need to be turned down to match to 348/409. Much like turning the mains down on a 400 Chevy crank to fit in a 350 block to make a 383 stroker. The rod journals will naturally stay Big Block Chevy, you can stay with the stock Big Block length or go with a number of commonly available longer lengths such as +.250, +.400, and get Ross or JE to supply the matching piston to finish your package! Also, 409 guru Lamar Walden around Atlanta,Ga. has been there and done that for over 30+ years, he can steer you in the right direction for what you want to do.
Don't turn down the mains...If you had to turn down any other crank that far to "clean it up" you'd throw it away. How many of us pass on a crank that's been turned .020 on the mains to clean it up? Go with aftermarket 4-bolt main caps and align-bore the block. -Brad
Turning down the mains for this application is a little different than having a crank cut .020" for a cleanup. There is really nothing wrong with a crank turned down .020" so long as it was done properly-actually the less the bearing surface area, the less friction etc... To have a 454 type crank turned down to fit 409-348 mains is much more like having the rod journals off set ground for different rods and or stroking the motor. There is a guy in CT with a 55 chevy running a 348 with a 366(?) truck crank. had to turn the mains and shorten the snout I think. I can try to get more info when I see him next, could be a while. What happened to the Buick motor project? I see it sold but what changed your mind?
go to 348-409.com like the other guy said. go to the forum and look up posts by "CDNpontiac409guy" he is very knowledgeable on this build.
i had too thin the herd .. i still have a nailhead, 3 sbc, 3 bbc ,1 y block,i 392, 1 421,1 348 somethings had to go, no room
You must have a small garage or something. 10 motors isn't that many. Don't you use the trunks of your cars for storage in the winter?Just kidding, right now I have 4sbc, 5 nailheads and probably about 16-18 different trannies in my garage. Not to mention all the chevy and olds rears etc... Still manage to get three cars in with just enough room to work on them plus all the tools/equip.
Your answer(Brad54), about installing 4 bolt main caps had absolutely nothing to do with the question that was asked about installing a BBC crank into a 348/409. What page are you on....
"there was a tread about making a 348 a 408 using a 427 crank,,,anyone know hows its done..." W-motors have a 2.50-inch main journal diameter. All other BBCs have a 2.75. I get a little nervous knocking a quarter inch off the mains. That's a whole lot different than off-set grinding rod journals. Grinding a 400 crank down to fit a 350, in the common 383 combo, goes from the 400's main journal ID of 2.65" down to 2.45". That's .200: would you want to turn that another .050? You just need to ask yourself if you're comfortable buying a big block crank that was turned .050, or even a 350 crank that was turned .050. I wouldn't be, but to each his own. We're putting Pro Gram Engineering 4-bolt mains in my 482-ci stroker 409, and I recommend it for everyone building a stroked W-motor. Lamar Walden is building the engine, and I've done several stories with him over the last few years. We've talked in depth about this, and I can't argue with his logic. Or his reputation or history. -Brad
There are three ways to deal with a situation where something won't fit in a hole because it's too big...you can make the thing that goes in the hole smaller, or you can make the hole bigger, or you can do both. Brad suggested making the hole bigger.
454 crank into a 409.Besides 400 turned down to fit a 350, Mopar guys are turning down 360 cranks fron 2.80 to 2.50 for 318 & 340 strokers.
You might check here for some ideas. You can buy a crank that is ready to drop in for around $400.00 exchange. If using a factory forged crank scares you, you can buy aftermarket cranks too. Look around on the site below. Check the link pages too. http://www.348-409.com/forum/forumdisplay.php?s=&daysprune=&f=9 http://www.348-409.com/forum/search.php?searchid=171861
I agree that turning the mains down that far to install the BBC crank is questionable, but that's how it is(was) done before aftermarket stroker cranks began to come on the scene. Align boring the block that much would probably end up boring into the main bolts. Also killing the possibility of returning the block back to its original 348/409 configuration if the owner chose to do so at a later time with out having to make a bearing spacer or something to fix to housing bore, and spending a bunch of money. Also, thats why I mentioned for him to contact Lamar Walden about his needs, because I knew Lamar had done this modification back in the day many times and could guide him in the best direction.
I'll make that easy. And I quote: "If you turned a crank down that far for any other engine, you'd throw the fucker on the scrap pile, so why would you put it in a $2,000 409 block?" "You can keep the stock 2-bolt mains, and turn the crank down if you want, but that crank will start whipping around like a piece of licorice, and rip the mains right out of it." Lamar Walden Automotive: (770) 449-0315. Tell him Brad said to call. According to Lamar, you'll want straight up-and-down bolts, not splayed caps, because there isn't enough meat in the webs to use splayed caps. Align boring it from 2.50-inch to 2.75-inch is going into the block .125-inch (1/8-inch) on each side of the crank center. Moving the bore 1/8-inch on each side is still plenty far enough from the main bolts. You won't be hitting them. I'm not trying to get into a pissing match or contest--I don't have that much first-hand "I've done it" with 409s...However, I've written a bunch of magazine articles with Lamar, and I've spent hours and hours talking with him at his shop, looking at what he's doing, getting "tours" of the 409s he's building, and generally collecting a ton of info from him. We're talking about writing a book on them. Plus I'm having him build my 482-inch 409. Over the Thanksgiving holiday, I went up to Cleveland and shot pics of the caps being made at ProGram, and talked to the owner for a whole day. He cut his teeth on 409s, and Lamar was one of his first customers, for 409 main caps. Between T-day and now, I've been down at Lamar's shop talking about 409s, mains, aluminum heads and intakes. CNCDude suggested calling him, and I agree. I'll bet a sizeable amount of money that Lamar will suggest 4-bolt mains in any W that's going to make some power. If it's a choice between turning down a crank or 4-bolt caps, he'll tell you in no uncertain terms which he thinks is better, and why. -Brad
348 with a 409 crank: 380ci 348 with a 427 crank: 408ci 348 with a 454 crank: 433ci That's all with a .030-overbore. Stock 348 bore is 4.125, with 3.250 stroke. 409 is 4.312 (!) with a 3.50 stroke. 427: 4.250 bore x 3.76 stroke. 454: 4.250 bore x 4.00 stroke. Not sure what a big ol' 4-inch stroke would do to the piston pin height on a 348...I think it could be done, because the deck height on a 348 and 409 is the same as far as I know. A 454 crank might be easier/cheaper to come by. Lamar hasn't shown me a big love for the 348, but I know he's got a new intake that'll work on it, and I've seen him carve forged pistons. Unless you've got a 427 crank laying around, then it makes a ton of sense. I'm in the same boat with the 409 crank out of mine. (and oil pan, intake, valve covers, etc.) -Brad
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