mytmouz

We used the small base circle, since it was already on hand. Whether you need to or not will depend on the rods you use, IMO. The motor runs good, it's still in use. It ran mid 10's in a fairly heavy vehicle on motor only.

zipper06

Unless you already have the 4" stroke crank, i would go to 3.875. This way you can use a conventional grind cam. I personally have a 434" dart blk. with Lunatti promod rods and bullit ground me a .875 base circle 4/7 cam for the motor, it's a .688/.668 lift and i plan to use 1.6 rockers. But to answer your question more directly, yes you have to use a small base circle cam, .900 or less even with "H" beam rods with a 400 blk or a 350 blk.
Between my friend and i we have (5) 434" motors and (3) with dart blks. and 2 with 400 blks. all have spladed caps and all have small base circle cams and all run on alcohol.
Now the combo i mentioned above 3.875 crank. I have a friend living a few miles away that will only run 350 blks. with 3.875 ultra light cranks an alum rods with light weight pistons. He runs 394's with 2" crank pins and 420Gm pistons on an alcohol toilet bowl, in a shoebox 55 chevy weighing 2650lbs. with driver. It will run 9.20's all day long at 142mph at twin cities,La.
It hurts lots of B/BLK people to hear this but it's a fact. i'm getting ready to put my 434" into my 3250lb Malibu and fully expect it to dip deep into the 9's @ over 140mph, estimating 5.80's or better in the 1/8 mi.
One of the 434" stock blk. motors i mentioned runs 4.80's in a dragsters and has over 200 passes on it.

JMO

Zip.