My question, Is there a problem using a 4.15 crank and 6.385 rod in a 400 block?

Regardless of if you buy the parts there or not, the 440Source web page has lots of good information regarding the different combinations for B/RB blocks . http://www.440source.com

Darren

I believe its been done sucessfully. You'll wind up with a short rod/long stroke engine and a "decent" compression height piston. A good aftermarket rod would be needed to hold up reliably. Piston side load will be on the high side. Other possile combinations are:

4.15 stroke/6.76 Chrysler rod: longer rod, short piston, higher rod ratio

3.9 stroke/6.7 BBC rod: longer rod, "decent" compression height piston. Proven durability in street & street/strip application.

4.25 stroke/6.535 BBC rod: max practical displacement with stock low deck block (my opinion), decent compression height, short rod ratio.

All these combos have trade-off's. Depending on where you're trying to get to with this engine, I'd choose one of the 3 above over the long stroke/short rod combo. My

6.385 is bigblock chevy plus 0.250"

6.358 is B block stock length

6.385 / 4.15 = 1.53 R/S ratio, almost identical to a stock chevy 454.
You may have problems with counterweights running into the crank, I have not studied this combo. The 6.535 rod is the more usual choice.

R.

My 73 has the 400 in it.
I was going to stroke it around 500 ci.
Looks like the 440 source is the way to go.
Now with the price of gas always going up,
looks like the truck might have to go up
forsale someday soon.