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View Full Version : Engine being set back....



mongoose
03-29-2008, 10:47 PM
Today I picked up a new frame for my cutty, and decided to do some really stilly crap to it... Almost scary..

motor has aluminum heads.. etc etc.. . alum water pump rad etc...fibre glass hood... power R&P..

Since I don't have any idea how to calculate weight bias... and changing it.. How much do you guys think a motor should be set back in a gbody?... more the merrier? I was going to go about 9 inches... Sound good? I can go back about 4" fairly easily.... But I don't think that would change a lot.

jackfrost
03-31-2008, 10:15 AM
nine inches? you'll have to cut the firewall out for that. since most guys are only able to set the motor back 1-2", I think you'll see a good improvement with the 4" you can get w/o modifying the firewall.

just curious, what R&P are you using? do you know how you will mount it?

mongoose
03-31-2008, 11:50 AM
I think it's out of a mustang?.... I can't remember.. the cheapest one they got on summit... haha, As for mounting.. I don't think it would be any different then the manual set up people are running.

novanutcase
03-31-2008, 05:23 PM
I think the general rule is as long as you can get the weight of the motor behind the front axle you're ahead of the game! Anything close to that will do!

John

gt1guy
03-31-2008, 10:38 PM
You'll gain more (weight distribution wise) from moving the battery to the trunk, than you will moving the motor/trans back just a couple inches. What moving the motor/trans back will help with is the Polar Moment. But, a move of just a couple inches isn't going to net much return there either. Cut the firewall, and you can go back enough to make a real difference.

I've moved the motor back in my 72 Camaro 14" and lowered it substantially. But it's a full tube chassis with a dry sump motor.

Kevin

mongoose
04-02-2008, 08:33 AM
Thanks for the info... I was think more than 9" would be better... but that gets a bit extreme imo... as far as fabrication goes...

What motor are you using? a lsX? got any pics? thanks.

gt1guy
04-02-2008, 09:03 PM
It a standard SBC....sort of. Actually I just ordered a 4.5" bore space Dart billet block set up to run RO7 heads. It will be a 435 with a 4.300" bore. Callies is doing the billet crank, and Kinsler is doing the IR EFI manifold. I'm working on the chassis now, I'll see if I can't snap a pic with the mock up engine in it to give you an idea of the set back.

Kevin

Ok, here you go. Driver will also be moved back 10ish inches. I know you can't see the marks on the 2x3 rect tubing for the front axle C/L in the picture (I can), but the front of the block is about a foot behind it.


https://static1.pt-content.com/images/noimg.gif


https://static1.pt-content.com/images/noimg.gif

mongoose
04-04-2008, 07:35 AM
Very nice. thanks for the pics. Since you're running a standard block, what are you doing for dizzy clearence? I'm thinking it would be easier to do that from that back.. IE like a van but are you leaving enough room to do it from the from? It looks like you have lots of hight there to play with..

I was only hoping to move myself back about 4 inches...

Marcus SC&C
04-04-2008, 10:18 AM
Moving the motor and trans back isn`t all that hard. Doing it so you can still sit in the car and work the gas pedal is harder. Unless your right leg is 6" shorter than the left,then disregard this. :)

G body is VERY hard to properly mount a conventional R&P in. There`s some very serious fab work involved including remounting the lower control arms. Do a search here. I think you`ll find it a LOT more work than it`s worth for potentially poor results. There are many more people out there with welders than their are who know how to properly engineer a steering system...
:drive1: Mark SC&C

gt1guy
04-04-2008, 11:52 PM
The plan is a front mount dist off the belt drive for the cam.

One leg 6" shorter would have made it much easier. Thanks Mark.

Kevin