I think that both breadfan and madmax make good points. I have heard very good things about using a 6" rod instead of 5.7 Smokey Yunick says its good, and thats good enough for me. There may very well be machining issues you need to take care of as madmax stated. If you're willing to spend the money, then it may be worth it. What kind of RPMs are you planning on running? I honestly dont think its worth spending the money to stroke a 400, but if you want to do it, you may as well see if a 6in rod will work. I would suggest doing your own research. Shop around your local speed/machine shops and see what they have to say. Better yet, go to the track and see what wins, and does what you want to do. You ask 3 different people, you'll probably get 3 differnt answers. Or you'll get someone like me who says very little, but takes a long time to say it. Hope it helps anyway.
Matt

 

How much you say? Well, how about 5.565-6.0, or .435"

At the very least, the piston will have a pin in the bottom ring land to prevent the bottom oil ring and expander from rotating around the piston. I personally dont look at that as an advantage. I dont think 1/16" top and second rings have an advantage either. People run stuff like that all the time I know, but I see it as another place for something to go wrong.

BTW, I didnt start any pissing match. I just offered my opinion that he'd be better off with 5.7" rods, and all of a sudden I 'need to do a little more research'. Sorry but I dont see the increased dwell time at TDC and 1 degree decrease in rod angularity as a big deal.

 

First off the only reason a 400 cid engine came with the smaller rod was to get the rotating weight down . other wise the crank would have been flexed to much . Next ,we are going from a 5.7 to a 6 inch not a 5.565 . And the oil ring wont be into the pin retainer , i have a set of 383 6 inch rods in my garage . the smaller rings are also reccomend for 383 that sees more than 6k rpm because of the higher piston speed . Its not about the increased dwell time at tdc i, its about the less friction , and the fact that longer dosn't see its top piston speed til further down the stroke , thus timing top speed with higher lift allowing more more air to enter the cyl , increasing volmetric efficiency . Isn't that what building a larger displacement engine is all about getting more air into the cylinders?

 

Well, we are talking about going from a 5.565 rod to a 6.0, because those are the rods used with a stock piston height, and a 400 crank. I'd be impressed if you took a 400 crank, a stock set of 350 pistons and rods, and threw them all into a 350 block and had it run.

Whatever though, I'm done arguing with you about it. Pointless.

 

acoording to chevy rumble #noc 2002 that the 6in vs 5.7 rod thing is just a myth...they said reher morrison racing engines did tests and proved that to be just a myth and helping little in the least of power...its sorta just like that big valve is always needed to make power...

 

Welllllll, i disagree with that. Like you said, big valves dont ALWAYS make more power. But a lot of times, they do...depending on the application. I think that there are many advantages to a long rod depending on the application. One of them may very well be increased engine longevity. Its tough to determine that on the dyno. My good friend Smokey Yunick (i wish) said that the longer the rod the better. Thats good enough for me. He forgot more about makin stuff go fast than you, me, or most anybody else will know in a lifetime.
Matt

 

You mean you're not friends with 'ol Smoke? (That's what I call him when it's just him and me on a project... ) Well I will do some checking. I'm still not convinced I want to go with a 400 though. I'd have to have steam holes drilled in the heads, etc. I just don't know... Parts seem to run a little more and for what? 20 more horses tops?

 

Woah there buddy. There are a fair number of advantages to a 400. Steam holes are not a big deal at all, you can do them in less than a half hour with a hand drill. So thats not an excuse. Quality parts are generally going to be expensive, thats just the nature of the animal that is speed. Keep in mind the old adage that there is no replacement for displacement. There are a number of reasons that this is true. Generally, a 2 similar top ends will make more torque and similar horsepower with a larger displacement. You also need to keep in mind that if you make the same power with a 350 as you do with a 400, the 400 is not working as hard. Larger displacement means less work for the same power. This translates directly to engine wear and longevity. Prices for parts should be relatively similar...are you going for a completely new bottom end no matter if its a 400 or a 350?
matt

 

Yes I am going for a completely new bottom end with forged components. I AM striving for longevity so you do bring up a VERY valid point. It just sounds so much cooler to go "I have a 383" instead of "It's a 406". Well, maybe not... It's just the only Car Craft build up I have found on a 400 made 520 HP and cost $9,700!!!! That's WAY out there for the power, when a couple of issues ago they made 540 HP for 4,800 with a 350. That's why the cost scares me so...

 

I have a feeling you can make a WHOLE lot more power for a whole lot less. Although forged components will set you back a pretty penny. The new April issue of CHP has a bunch of "Big-inch small-blocks" in it. There are also a fair number of advertisements for forged stroker kits for 400s. Im not convinced it will be significantly more expensive in the long run for a forged bottom end in a 400 than a 383. There has also been a build up in one of these magazines of the HT383 crate engine that makes incredible power, and comes with a 4340 forged crank. The same issue of CHP made a 530HP street 383. Again, it is up to you and your wallet. Forged assemblys do tend to last longer, so the difference in longevity may be minimal until you begin making a whole lot of power. But 406 definietly sounds cooler than 383. I dont care what your woman tells you, size does matter.
Matt
ps wow this is a great way to avoid actual homework

 

Well I will have to go buy that magazine then. Thanks for the info. If I could get a stroker kit for the 400, all the better. However I heard they were REALLY expensive, and I wasn't looking at spending more than $1,300 for a bottom end.... As for the homework comment. Yes it is.

 

I dont have the advertisements with me, but I dont remmber them being a whole lot more expensive than a 383. I have a feeling that the machine work, however, may cost a bit more. Give some stroker companies a call, and see what work will be required and what they reccomend for your application. I think they may know a bit more than me (i doubt it tho ). Competition products (800-233-0199), Crower (619-422-1191), Eagle, and Scat can all probably provide the answers youre lookin for. I didnt really feel like typin more fone numbers...you do the work.
matt:lala:

 

Thanks for the info. I will look into it this weekend. So if a 400 is stroked what would that make it?

 

Cant guarantee this, but I think if it is stock bore it is a 427 and if it is bored over(30 I think) It is a 434. I have seen the numbers but I cant remember if that is quite right but it is at least close.

Ben

 

With those kind of numbers 500 HP on pump gas should be pretty easily accomplished...

 

Yeah, and imagine the people that would ague that you didnt know what you were talking about when you said you had a 427 and they looked under the hood and saw a small block. Then you just smoke um.

Ben

 

Of course, the whole time I will be saying it's a "typical small block".... Plus I don't plan on having any "pretty, shiny" things under my hood.

 

Uh ya, I fixed up the 305 a bit. lol

Ben

 

Actually, that article i was telling you about? World is workin on a 454 small block. Holy crap that would be huge. They are currently doing initial dyno testing on that block, and have a 443 putting out over 600 hp on pump gas easy. Somebody named Shafiroff sells a 434 unassembled shortblock and assembled shortblocks. 3900 and 4300 respectively. PICK UP THE MAGAZINE. Its got a thirdgen on the cover for cryin out loud.
Matt