WHAT ROD LENGHT GOES BEST WITH 4.250 CRANKS [Archive]

View Full Version : WHAT ROD LENGHT GOES BEST WITH 4.250 CRANKS

65+PLEASE

10-12-2003, 02:54 PM

I HAVE DECIDED TO GO WITH A 496ci. I HAVE A 5140 STEEL 4.250 CRANK. I WILL BE USING A GEN IV BLOCK. MY CONCERN IS ROD ANGLE. WHICH LENGHT ROD WILL GIVE ME THE BEST ROD ANGLE.
RICH

Badboat1

10-12-2003, 03:10 PM

6.385 for the best bang for the buck as you can buy a shelf piston for that.

Racing Ray

10-12-2003, 04:40 PM

I run 6.585 in 2 of my engines, that is .400 long. I also use Venolia pistons in one and BME in the other, both are off the shelf pistons.
This will relocate the wrist pin into the oil ring groove and you will either need to use a support ring or plugs to cap the oil ring groove. Either way works fine. It will give you the best possible rod angle for your low deck block.

Fiat48

10-13-2003, 06:48 PM

Racing Ray:
I run 6.585 in 2 of my engines, that is .400 long. I also use Venolia pistons in one and BME in the other, both are off the shelf pistons.
This will relocate the wrist pin into the oil ring groove and you will either need to use a support ring or plugs to cap the oil ring groove. Either way works fine. It will give you the best possible rod angle for your low deck block. Amen to that.

565edge

10-13-2003, 07:01 PM

I also run the .400 long rod with 4.250 stroke in a short deck with no problems with a shelf je piston.They are now putting 4.375 stroke cranks with a .400 long rod in shortdeck motors.

Badboat1

10-13-2003, 07:27 PM

Yep they are doing that now damnit lol.I have 6.700 rods in mine with a 4.500 stroke crank.Any one know how to figure rod ratio??????????.Sorry 10.200 deck also.But no prob putting .400 long rods in a short deck with 4.375 stroke.I been doing that for how many years.Forgot How long.....................
I guess not

Infomaniac

10-13-2003, 07:35 PM

1.48 Randy. Stock 454 is 1.52
400 long with 4.375 is 1.49
6.585 is 450 long

Infomaniac

10-13-2003, 07:40 PM

400 long in a 9.8 deck block with a 4.375 stroke crank only leaves 1.077 compression height eek! eek!
I don't think I will be going there.

Racing Ray

10-13-2003, 08:01 PM

Infomaniac:
6.585 is 450 long Oops your right, my bad.

Infomaniac

10-13-2003, 08:06 PM

I just figured you were like me. The fingers do not necessairily type what the brain is thinking.
wink

Badboat1

10-14-2003, 05:50 PM

Yep long day yesterday 6.135 is stock and 6.535 is 400 long and yes info have that combo in a engine but .043/.043/ 3/16 rings and top ring back cut also.Not a shelf piston

Fiat48

10-15-2003, 08:56 PM

I thought the .585 looked "funny" but didn't catch it. That's real bad as everything I have runs 400 long and 3 boxes of spares in the shop. Old age, old eyes. frown

Cs19

10-15-2003, 09:02 PM

what are your guys thoughts on this combo for my jetboat motor? as far as the ratio? Tall deck gm block ,4.250 stroke scat crank,.400 long carillo rod. probaly go .030 over on the bore, with custom pistons from cp.