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Crank support

17K views 42 replies 20 participants last post by  BigblockXW 
#1 ·
Hi, I am building a 8/71 supercharged 501, 385 series stroker. Has anyone here modified the spacer behind the balancer to use as a crank support? This is going into an Australian 1974 Falcon, so I don't have much space behind the radiator support panel to modify a front mount Chevy style support.
 
#2 ·
You can probably get by without a crank support, I know of alot that are not running one, and I'm not planning on running one with mine. Guess it depends on how hard you are going to run it. If its a street/strip deal then I think you'll be okay without it. Hopefully you are using a forged crank? Chris
 
#3 ·
Yeah, a couple of builders have said the same, but, I like the idea of having a little extra insurance, and they all said "I probably shouldn't need it", which doesn't sound very confident. That blower pulley is a long way out from No. 1 Mains. I am pretty sure we have it nutted out, but I was hoping someone had already tried it.
 
#4 ·
IMHO, you are approaching a "serious" supercharged race motor incorrectly. You are correct in being suspicious about the strength of the long, slender snout...we've broken a few. I'd start with a crank, probably a billet, ordered with a BBC snout as it's the largest diameter one that parts are generally available for. It's also much shorter and therefore stronger and won't require a support. Just substitute a BBC timing gear for the crank gear in your timing set as MOST are the same diameter. A simple ring adapter will allow the BBC front seal to fit the timing cover. The front cover can be slimmed down for belt clearance BUT, a stock waterpump is out of the question. The bad
part is that there is NO manifold to fit this combination, you must fabricate one. It's not a big problem...just expensive.:)
 
#5 · (Edited)
Another option is to use a 429 forged truck crank. The snout can be turned down to either a Chevy or Mopar diameter. You can shorten the snout as well. You'll only be able to get 3.85 stroke with a 2.2 rod journal with that crank, but that is the beauty with a blower, just change pulleys and get more boost.

If you're looking to go over-kill, just use the 429 forged truck crank's snout as is. BHJ can make you a custom damper/hub. You won't have to worry about breaking that. That will require some custom work for the front seal and spacer.

Hope that helps,

Dave
 
#8 ·
All sorted, modified the spacer and have the bearing sitting inside the harmonic balancer. Still has thrust movement and the support is about 3" from the front of the crank. You can hardly see it which is even better. I will try and post some pics.
 
#15 ·
Thanks, Critters. Can't remember the bearing size, but it is about 25mm wide and pressed into an alloy retainer that fits neatly inside the is then bolted to the support plate. And yes, aussie Falcons are all front sump pan, this one has been internally modified with a gate.
 
#18 ·
Passenger car heads still have their place. An 8-71 blown 501 with well prepped passenger car heads can easily make over 1000 hp, possibly 2000 hp depending on the combo...or more if you want to tilt the can.

Aluminum heads are not always a mandatory part of an engine build.

Paul
 
#25 ·
I am running an alternator, I may change to electric pump down the track. Trusty old Mallory fits under the blower.
 
#19 · (Edited)

This looks like a very clever setup. The location of the crank support allows for a minimal amount of material needed
for fabrication, is also compact in design by way of its location, and lastly keeps the front of the engine from
getting too "busy" with a plethora of accessory parts.

In an all-out application, placing the support at the very end of the snout will technically offer greater support,
both by the crank support "leveraging" the end of the snout and by placing the blower pulley inboard
of the support and thereby minmizing its leverage.

Nice setup; you'll be fine.

Paul
 
#29 ·
Getting closer, I have had to put this project on the backburner for a while, back into it now. All fitted in place, working on fuel lines and wiring now.
 

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