407 Rods December 15, 2011 11:39AM
Are 407 rods a direct fit in a 414 or do they need to be machined? From what i could find there are 2 different diameters for the wrist pins and i'm not sure which ones to use. Does anyone have a set for sale? Thanks
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Re: 407 Rods December 15, 2011 02:38PM
The 407 rods are longer than the 400 series motor by about .350" so you can't just swap them. You would have to go to a piston with that much less wrist pin to top of piston clearance. You are right about there being two different pin diameters. Most are 1 1/2" with some later, higher horsepower, motors had a 1 5/8" pin. Of course the 400 series motors had the 1 5/8" pin.
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Re: 407 Rods December 16, 2011 05:10AM
Thanks! Any idea what pistons would work with the 407 rod in a 414? Also how does that rod increase the torque? I was told the angle at ignition is different. Is that true?
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Re: 407 Rods December 16, 2011 05:38AM
You can use the small pin rods. knock the bushing out and hone the whole a lil bit and it will work fine. i might have a set. i know i have a set of deere rods machined to fit ih crank would be a better setup if you are running alot of horse power. my number 660-373-0440
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Re: 407 Rods December 16, 2011 01:39PM
Take 466 pistons machine .060-.075 0ff the top and hang them on big wrist pin 407 rods and bolt them to a 414 crank. I do not know if you will have any rod clearance issues. Maybe someone has tried this?
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Re: 407 Rods December 16, 2011 02:56PM
" done it "is right, get 466 pistons, mill about 60 thousands off the top, put them on 407 big pin rods and bolt the rods to your 414 crank. Dont forget to cut valve reliefs also especially if your gonna use a higher lift cam. If your competeing in a "no turbo" or naturally asperated class you can use 436 pistons, cut even more off the top, which lessens the volume in your combustion bowl thus increasing your compression ratio for more power. I have some extra 407 1.625 pin, (same as 466 or 436 pin) rods around if your interested. This setup works well togather. Dave 605 553 1504
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Re: 407 Rods December 16, 2011 03:45PM
How many rpms does this setup run, Drifter?
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Re: 407 Rods December 16, 2011 05:02PM
If the rods are hardened and the assembly balanced (crank, rods, pistons,flywheel,balencer,rings, bearings,ect.) shoudnt have a problem turning 5000 or better.
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Re: 407 Rods December 17, 2011 01:49AM
is it a 466 0r 414 cu?
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Re: 407 Rods December 17, 2011 03:22AM
It'd still be a 414, the bore and the length of the stroke would remain unchanged. The only thing that would change by using a 407 is the angle of the rod during the revolutions of the crankshaft.
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Re: 407 Rods December 17, 2011 03:54AM
I know this is a popular combination, but has anybody seen an actual dyno comparison of a 414 with 407 rods vs a 414 with stock rods? It sure seems to me like a lot of trouble for potentially small gain, and I would personally think that money would be better spent on head work, turbo, etc. Anybody have any hard numbers?
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Re: 407 Rods December 17, 2011 05:06AM
One of Reher-Morrison's tech articles once upon a time discussed this (I believe they are published in National Dragster). They did a test of different rod lengths while maintaining the same piston weight and stroke and found no difference in performance of varying rod lengths.
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Re: 407 Rods December 17, 2011 08:23AM
I believe rod angle is the key to the whole package. There are some small horsepower gains but there are bigger gains in durability.
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Re: 407 Rods December 17, 2011 05:07PM
I believe rod/stroke ratio is the key. Considering rod length without considering accompanying stroke is a moot point. Stock 400 series rods and a 4.75 stroke will yield a ratio of 1.78-1 and a 4.75 stroke with 407 rods yields a ratio of 1.84-1, both of which are nearly ideal. Still not really seeing the benefit. Dyno numbers, please.
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Re: 407 Rods December 17, 2011 05:24PM
A longer connecting rod for a given stroke allows the piston to dwell longer at TDC before it starts back down on the power stroke. This allows pressure to build longer in the combustion chamber before it starts to shove the piston down. The result is usually a broader, flatter torque curve than the same engine with shorter rods. An engine's horsepower and torque curves depend on a lot of variables other than rod length alone but if everything else is equal, the longer rod will produce a broader torque curve.Thumbs Up
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Re: 407 Rods December 18, 2011 01:06AM
I am not seeing this?
Rod ratio on dwell?

durability yes.

HP slightly.
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Re: 407 Rods December 18, 2011 01:48AM
other rod stuff was posted on May 20, 2010 02:45PM
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Re: 407 Rods January 10, 2012 03:26PM
You can use a small pin rod drive the bushing out and and bore out to fit pin allow .005 clearance for oil should be fine. We done it on a 3200 rpm tractor
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Re: 407 Rods January 15, 2012 05:14AM
KBacker,
In the test you're referring to, did they ensure that the different pistons used maintained the same mass/weight, or were the shorter compression height pistons also lighter because of a shorter skirt?

Just asking,
Arthur
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Re: 407 Rods January 15, 2012 08:00AM
The only difference in the pistons was the pin height. Pistons were from same manufacturer, compression,valve relief,skirts,same style rings,everything to isolate the long rod theory.
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Re: 407 Rods January 10, 2012 03:31PM
The only real notice we seen was piston to cylinder wall drag,the pistons didn't show as much wear as did the shorter rods.
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Re: 407 Rods January 13, 2012 09:21AM
rod length has nothing to do with how long the piston stays at the top or bottom,its in the stroke of the crank, simple physics tell u that, only gain is small durability at best
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Re: 407 Rods January 13, 2012 11:09AM
Sounds like the long rodded case 504 would be the ideal pulling motor. lol I also would like to see some dyno data.
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Re: 407 Rods January 13, 2012 02:24PM
I'm guessing m8888ja has never built a performance engine?
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Re: 407 Rods January 14, 2012 01:37AM
rod length has everything to do with dwell time!
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Re: 407 Rods January 14, 2012 01:44AM
rod length changes dwell time a bunch
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Re: 407 Rods January 14, 2012 09:38AM
rpm's = ground speed,, name of the game,thats simple
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Re: 407 Rods January 14, 2012 12:45PM
BUT how you get that rpm is very important. Back in my drag racing days and smallblock chevy run on a dyno 2 engines were run with the only difference being 5.7" rod vrs 6" rod (compression ratio was maintained by using pistons with a higher pin location) ............ Long rods made 75 ft lbs more torque and 10 hp at like for like average runs. Doesnt sonund like much huh? ............ it truley is the little things that makes all the difference.
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Re: 407 Rods January 14, 2012 02:11PM
Like I said I'm guessing m8888ja has not built a performance engine of any kind? Oh by the way TORQUE turns the tires!Thumbs Up
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Re: 407 Rods January 15, 2012 04:02AM
I would call 10 hp and 75 lbs tourque significant.
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Re: 407 Rods January 15, 2012 04:45AM
LOL yes it really is BUT to the masses 10 hp and 75lbs torque doesnt sound like much. And most dont understand that SF engines are currently worked to DEATH on a dyno just to find a couple hp and a few more lbs torque. Even the top running 3000 rpm guys are working them hard at a dyno. EVERY little thing helps that # and a long rod engine is one of those things.
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