The stroke is reduced to 3.96 from the 4.05 that the Indy block has. Looks like the rod ratio would be 6.125/3.96 or 1.546. The Indy block ratio would be 6.125/4.05 or 1.512. I thought I read somewhere that 1.6 was the lowest desireable rod ratio. C.
A 1.50 rod/stroke ratio is nothing. The Ford guys build 347's all day and the chevy guys build 383's and both of those motors are right in line with what the 392/426 is and they dont have any issues with longevity. Even the chevy 454 a worse rod/stroke ratio. If it was me, I would sleeve a 6.1 block and drop bore size down to 3.92, get a billet 3.58 crank with billet rods and forged pistons, then I would boost the hell out of it and not worry about parts breaking.
There are alot of different companies making engine cubes with different combos. Now that tuning is available I am looking for alot more goodies to be available by this fall or so.
Actually Andy it is the most undesirable rod / ratio any engine builder wants to see. Any for street machines a 1.65 and up rod ratio is desirable anything in the .50's is not. Nothing says it will not run but you can make more power with an ideal rod ratio vs the other. Do some research you'll see, it's common knowledge.
:muscle: Not much of it. Lol To be exact and all... 345.56 or 346ci. We would need to feed it like 20/lbs. of boost. Lol Btw, the gentlemen I spoke to at Superior said, "I don't see the advantage of building a 440ci motor... not enough displacement or cubes over the existing 426ci output... they have not actually done any or plan to do any. When I asked they really didn't want to do it for some reason.
Not to go off topic and all, but i have a blower cam that would rock your world... when your ready or you trust me lol. Valve notched pistons are definately needed... and you have them. :dance4:
BTW: The guy at Superior said he has some new valves for our cars coming out in the next few weeks. He says they will support dual spring valve springs. He said the single springs on our cars are going to fail, it is just a matter of when. C.
We worked with superior on developing the sleeve kit, The first one was on our Car(6.8L 300srt8) I personally dont think that the sleeve kit is the way to go, lots of things to go wrong or not seal and there were hot spots that developed on some of the sleeve motors causing the rings to be eaten. The proprietary spring package we Sell ran the entire year on the rev-limiter on the Chrysler drift car and was developed on a spin tron they are made for our Hemi's and is not just a GM transplant. Scott
Hey Scott, what's going down besides the price on your spring setup...lol. Do you guys have any in stock and how much money is trying to leave my pockets again?
This rod ratio thing is confusing. If the 383 chevy crowd is having luck with the same rod ratio, then what are the trade offs with rod ratios in the 1.5s and say cylinder wear, etc? I think the stock ratio is like 1.77 on the SRT. C.
The SRT8's rod ratio is 1.74 to be exact... The Mopar 392 has a rod ratio of 1.63. Do you see the trend here? Anytime you change the stroke to increase cubes, it's going to effect the rod ratio... unless you increase the deck height or lengthen the rods being used. Anyone out there making a 1/4 inch head gasket. Lol :bang:
I need an expert opinion. In this article in Hot Rod about the sleeves, they sonic check a block and say it has .170 to .102 inches of metal. They say they need to remove .080 and then say it would leave an impossible .022 cylinder wall thickness. If you remove .080, aren't you removing .04 all the way around and thus the wall thickness at the thinnest point in this example would be .062 instead of .022? C.
I know the old saying "there's no replacement for displacement" but now that some better options are coming on line, and tuning is easier and better, why not focus on building forged bottom ends with lower compression pistons, and just boost the daylights out of these things? Might actually be a more durable solution, no? We're just now starting to run into TCM/transmission problems as the next roadblock anyway. Just thinking out loud.
By no means am I an expert, but to get a 426 out of a 6.1 with a 4.05 crank, you need a 4.090 bore which is .035 more than stock. That equals .0175 all the way around and if the thinest spot is .102, that spot is now .0845 which is plenty for an everyday driver. If you are one that thinks .0845 is too thin, .102 isnt much better. in order to make a 440, you would need the 4.080 crank and a bore of 4.145 which is a .090 overbore which would leave you with .057 of cylinder wall thickness at its thinest spot. I will take my 4.050/4.080 crank and 4.065 bore all day instead of the sleeved block IMO. It may only be 418-420 cubes, but its close enough. lol.
Thanks Andy. Actually I am thinking about a 4.225 bore and a 3.795 (Chrysler 392 crank). The sleeves are at 4.055 and have a .175 thickness. I am thinking about removing .085 all the way around to get to 4.225. That leaves .09 all the way around. I believe the sleeve metal is much better material as well so if .102 is what a stock block has, then .09 ought to be OK with these better metal sleeves. This combo would also give me a rod ratio of 1.613 or about the same as the Chrysler 392 crate motor. C.
