Offset ground 401 Crank

[badass86coupe]

Trying to get some opinions here.

How strong do you think a 401 crank would be that is offset ground to a 2.1" chevy rod jurnal.

Here is the combo I am looking to build

401 block, crank all standard I want to offset grind the crank to chevy 2.1" rod bearings
will use a 5.850 chevy rod Eagle H-beam
custom piston with a 1.444 cr height at 9.0:1 cr
This will come out to 421ci with a .020" over bore
Will use Edelbrock heads
convert to hydraulic roller cam and lifters
Erson custom grind cam
Edelbrock EFI


this set up may get a custom twin turbo set up too


All said and done hope to make 525 at the flywheel on motor this motor is going into a 73 pro-street Jav

Thanks for all the feed back

[jeepsr4ever]

Should be fine! Many racers and offroaders use the Chevy 2.00 rod journal and a stroke of 3.900. Some use a Honda journal (1.889) and a stroke of 4.025+.

[badass86coupe]

yeah but if you go to the 6.0 rod then you get into the oil ring with the pin and on a street car thatr can cause oiling problems. You think I will reach the hp goal with this combo and you think it would handle the power of turbos

But if we go with a 2.1 rod jurnal and a 6.00 rod a 1.29 cr heigth should not get into the oil ring right

[jeepsr4ever]

Ring spacing can be altered depending on what type of material is used and if you want a thick upper ring land for NOS or blower applications. Even with a 3.9" stroke and a 1.259 compression height your pin diameter at .927/2=.4635" so you will have .7955" to work with which makes for a tight ring pack if you want a .300 or .312 upper ring land. Piston mfgs will tell you that even if you enter the wrist pin area with the oil control rings you shouldnt have bad street manners (smoking). I have seen many strokers using custom pistons not smoke from low oil control ring lands. I have seen these stroker smoke when you use a rod with a thinner width allowing more than .020" play between the rods and the width of the rod journal. This is common when you run a 2.000 rod bearing on a AMC 360 crank due to the width of the 360/304 rods (wider than chevy). But even that can be taken up with a good crank scraper.

[badass86coupe]

I was going to use a 401 crank offset ground to the 2.1 bearing size with a 6.0 h-beam rod if it will be an issue I will just stay at 401 with a .020 over bore and run it

[jeepsr4ever]

No it shouldnt be an issue.

[badass86coupe]

Thanks for the help :mrgreen:

[radamx]

1162 hp on 400 hp Nitrous with 2.100 rod pin with 6 inch rods.
factrory crank .
I have run 500 hp Nitrous for a couple of trips to the track but no dyno #'s
3 years and no problems