Moving the engine back

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MidTexCuda

MidTexCuda

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My motor will be coming out this winter for repairs so i need a project. I was comptemplating moving the engine back a couple of inches (steering permited) and was wondering it it would be worth it. I know the work involved and it would be no issue but time and a small expense.
The car is a full race 68 Cuda that is gutted. Big block, big tire, on coilovers, ect....
May even look at moving the fire wall back far enough to hop the steering. (Brakes and gas not an issue)
Any thoughts?
 
If it's a back-half car I'd think it would help a bit because of how the weight transfer is handled and how it affects the rear suspension. A purposebuilt tube frame car it's less of a bonus. That being siad I think the distance needs to be greater than 3" for it to really help much. It's a ton of work in a production car nose. Headers and engine servicing (like valve cover removal and head removal) are the hardest things to overcome.
 
I had a friend move his back 2" in a 1968 GTX. He had to alter the firewall and the steering, by the time he was done and back racing a few months he said never again. 68 GTX tubbed, narrowed danna cal-trac car. He's a Former NHRA Div.1 Champ. and been racer for years.
 
Looked at the car last night. I can move the engine back 6” with a rear sump pan and a crap load of work…. That would move the firewall to the seam line the stock floor pan. It would require moving the engine back 14’ to hop the stock steering with the current pan. Way to much work and no leg room.
My gas, break, steering, and trans mount will not be any issue. Looks like I will need a new pan and the drive shaft trimmed down.
I know it’s a huge undertaking but will 6” move rearward make any difference in 60’ times?
 
MidTexCuda said:
Looked at the car last night. I can move the engine back 6” with a rear sump pan and a crap load of work…. That would move the firewall to the seam line the stock floor pan. It would require moving the engine back 14’ to hop the stock steering with the current pan. Way to much work and no leg room.
My gas, break, steering, and trans mount will not be any issue. Looks like I will need a new pan and the drive shaft trimmed down.
I know it’s a huge undertaking but will 6” move rearward make any difference in 60’ times?
Click to expand...


its only going to go as fast as the rear tires will allow it, and I don't think 6" will add very much weight rearward
 
You still need to do some homework for the exsiting center of gravity. Once you have the 4 wheel scales this site has a calculator for it...

http://robrobinette.com/cg_height_calc.htm

The lighter the car, the greater the affect. So a back half A body I'd figure will run close to 3K w/driver, maybe more depending. So I'd think 6" will make a decent difference. Whether it's enough to make it all worth while - that's another story...lol.
 
Moving the engine back moves approx 100 pounds onto the rear axle per inch. Is it worth it? Maybe if it was an autocross car, but a dedicated drag car that hooks well will not see any improvement in ET or 60 foot. If the car is traction limited and having problems hooking after sorting it out as best as possible then I could see where it could make a difference. But again, that would be a last resort to me.
 
Guitar Jones said:
Moving the engine back moves approx 100 pounds onto the rear axle per inch. Is it worth it? Maybe if it was an autocross car, but a dedicated drag car that hooks well will not see any improvement in ET or 60 foot. If the car is traction limited and having problems hooking after sorting it out as best as possible then I could see where it could make a difference. But again, that would be a last resort to me.
Click to expand...

I agree ... What is the et 60' and mph on the car? Weight?
 
Guitar--- Thats what i was loking for. I currently dont have any real traction issues, it slips but grips. Nothing i couldnt get out in the shocks or bars. I was just currious if by moving the weight back if the car would transfer the weight more quickly thus turning the lift force into a forward force yielding .05 or greater improvements in my 60' time. What your say makes a lot of sense. If the tire grips the instant it starts to turn and doesnt slip the location of the weight it is pushing doesnt matter. it could be 20' in front of the car. the weight wouldn't change...

I havent weighed the car sense i changed some things but compared to my old weight slips i would say the car weighs around 2850 with me in it maybe less.

The car ran 9.97 @ 138 on 7 1/2 cylinders the last time i took it out would 60' at 1.34.

ton of other issues to work out when the engines comes out to repair ring issues.
 
I think the real thing you will get out of the car is a more consistent et... Might be easier to set it up for a slick track and a more consistent 60'. If all you are doing with it is bracket racing and doing it for points then I say do it.. If this is a fun car to play with and go to events and enjoy I would skip the extra work and finish working out any other issues the car has...

Just me...
 
Jones settled it for me. Im not doing it.

I have a lot of bugs to work out when the engine gets rebuilt. First being my converter. and maybe gears.
The car runs great and is too cosistent. i know that sounds crazy but i have run 1.34 to 1.57 60'. Launched in second from 2500RPM, gone from 1st straight to 3rd, shifted at 6k to 7k and the car always runs 9.97 to 10.00. 47 degrees to 95 the car runs the same. Max wedge port and pollish work to changing up and down 4 jet sizes and running on 7 holes and still runs 9.97 to 10.00 @ 137 to 139MPH.
 
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