396-454 crank in 409

[blown 409]

is there a thread someware (here) that gives spec on how far counter weights and bearing journals have to be machined, and how much and were to clearence block, my nieghbor is a retired machinest and does great work cheep $15 hr, id like to have him do the work but need spec,s Thank,s Tim

[boxerdog]

I know Aubrey has a drawing that describes what needs to happen, or you can ship it off to Show Cars and they will do it for you.

[Tom Kochtanek]

I handed a stock 409 crank and a 396 crank to my machinist friend, and he took the meaasurements off of the 409 crank and mated/matched them to the BBC crank. If you have one laying around, that's the easy way :).

Good luck!

TomK

[desapience]

is there a thread someware (here) that gives spec on how far counter weights and bearing journals have to be machined, and how much and were to clearence block, my nieghbor is a retired machinest and does great work cheep $15 hr, id like to have him do the work but need spec,s Thank,s Tim

TIM

YOU CAN BUY A FINISHED STROKER CRANK TO FIT THE 409 DIRECTLY FROM EAGLE. YOUR BLOCK SHOULD NOT NEED ANY MACHINING SO LONG AS YOU DO OT STROKE IT BEYOND A 454 STROKER CRANK.

DENIS

[heavy metal]

Beware you will need new rod to fit this crank as it has a 1/8 radius on the journals
or you will need your old rods machined to fit. plus different bearing to accommodate the rod crank combo.

[blown 409]

you dont??? need to do any grinding on block for clearence?

[CDNpontiac409guy]

Stock BBC 3.76" / 4.00" stroke crankshaft counter-weights do NOT clear inside a 348 or 409 block.
Most people / shops seem to feel that they have to do all that grinding and clearancing inside the block.
I do not agree with that method.
In my feeble opinion, it seems FAR more logical to remove the excess material from the outer surface of the leading and trailing edges of the counter-weights. This DOES remove a substantial amount of weight from the crankshaft... can actually be measured in pounds:eek: . Combine this, with a little die-grinder work in areas outside the throws, where there's excess "flash", ect.... and the crank can be balanced internally, no "heavy metal".... provided you select the correct pistons:coffee: .
What you end up with:
A rotating / reciprocating assembly that is litterally POUNDS lighter than an ordinary big block Chevy... or 409.... providing superior performance, longer bearing life, and vastly improved reliabilty.
....
oh
I guess I should mention also...
with this "lightened crank" method, there are instances where you COULD still end up spending UP TO 8 minutes with a die grinder, clearancing your block.

[Tom Kochtanek]

I followed Aubrey's advise some 3 years ago (396 crank) and spent less than 10 minutes with a die grinder on the inside of the block. I saved the "409 dust" and put it in a packet :). Magical stuff, that 409 dust!

Best,
TomK

[blown 409]

thank,s guys , Tim