Rear leaf suspension modifications

[Charlie Cheap]

I am building a 1967 Sunbeam Alpine and installing a Ford Lima 2.3 modified 4-cylinder with an A4LD overdrive automatic. At 75 I still love to drive but this is for long trips. That sounds crazy for a car with an 89 in wheelbase, but it is what I am doing.

The rear leaf suspension will be dismantled and rebuilt adding gas shocks and Teflon between the leafs. My question relates to Rubber or Poly bushings. I installed Poly bushings on my 65 Mustang and it helped overall handling on wavy roads. However, they seem to add road-feel to the driver, that is a little more than I want in a short wheel-base daily driver sportscar. I am not going racing, but may drive it across the US.

I have heard use polyethylene only in the front of the spring, while others say only in the rear, because the front transmits load to the chassis, right under the seats. I plan to use poly in the front sway-bar only, with rubber everywhere else. Control is my goal for a street car without the loss of too much comfort. For 50 years I built Street Rods but this is my first sportscar. Thanks.

 

[Ranger Mike]

ifin you want smooth rude go with stock bushings. Engineers spent thousands of hours and millions of dollars developing a good compromise between comfort and performance. If you want maximum performance go with metal bushings. The in between is poly bushings but as you have found out, they ride a little harsher. Put in the stock rubbers as they will out live you and me on this ride! I been bending wrenches on race cars since 1964.

 

[Charlie Cheap]

Thanks Mike. I got out of drag racing my Corvette powered 40 Ford coupe in 69, after being out run by a 413 HEMI powered station wagon. It was IHRA rules and his car went by title weight, while mine was weighed in at 3000 lbs. Because mine was a Chevy in a Ford I had to spot him one light. As I got into 3rd I was at his door and gaining fast...then cubic HP took over, and he beat me by a car of daylight. That was a factory Hot Rod Wagon and I had a much modified SBC and 4-speed. I quit that day. If the factory can out-run a Hot Rod, WHY BOTHER! That was 69 and ever since factory sponsors have controlled drag racing, putting us home-builders out of business. Thanks again for the answer.

 

[Ranger Mike]

my first drag race car was working on a 1963 Plymouth 426 Stage 3 factory drag car. It had factory all aluminum front end, fresh ram air hood scoop and tow carter AFB carbs on a stock short ram manifold. I would guess you were doomed from the start going up against the Chrysler 413 Wedge. Chrysler never had a stock HEMI of 413 cid. That race combination was developed over many many years by t he famed Ramcharger race team. This was a group of Chrysler factory engineers who loved drag racing and developed the whole muscle car program on their own after hours at the drag strip. These engines were flat out torque monsters and topped out at 7000 RPM. To beast them you needed a high revving small block Chevy turning 9500 RPM in a light chassis. Add to it the fact your 40 Coupe was as aero dynamaic as a brick compared to the sleeker Dodge wagon, and the extra rear end weight the wagon had, AND you had to spot him a light...well no wonder you got pulled on the high end.

 

[Charlie Cheap]

Thanks for the reminder Mike. Like most drag racers when I think of Chrysler 413, I think HEMI. Naturally I try to make the match-up look like I was robbed, but I just got out run by cubic inches, plexi-glass windows, no rear seats, Bucron rear tires (remember those?), and a factory race car. In reality the 40 coupe is very aerodynamic, but even with a 283 bored to 292", FI double hump heads (2.02 valves), Duntov solid Vette cam, 4-barrel, Doug Thorley headers, Mallory ignition, Schafer (sp), flywheel, Hayes clutch, Traction Masters and an Olds 4.11 (I think) rearend, it was not enough! At the time I was a Chevy guy and "assumed" I got beat by a HEMI. The other thing I remember about Green Valley Raceway is, I got to talk to Linda Vaughn. She was almost wearing a very low-cut top and very short mini-skirt. I had a picture...but the wife trashed it years ago. Thanks again for the Wedge reminder.