OK If your springs are not broken, they don't "need" to be replaced. But they will be weak, especially after 45-50 years of holding a car up.
Was the rear end changed after the engine swap was done ? Or was more than the rear end done at the same time ?
If the rear was the only thing done and now the front end sits high, you are not telling us something.
If you jack up the front of the car by the bumper or chassis and let the suspension drop.
The car will sit higher until you get the front end to settle back down. Normally driving a few feet will do it. Nothing special about it.
This is a list of approximate weights of various complete, assembled Chrysler Corp. engines obtained from various sources.
The 5.2 & 5.9 Magnum engines are not listed but should be slightly lighter than their LA counterparts.
70-71 E-body spring same for 225-383 standard.
72-74 2 different springs available a standard and a Heavy Duty.
Here is a weight chart. 360 weighs 75 lbs. more.
Engine | Weight |
Chrysler 331 Hemi | 700 |
Chrysler 300 Poly V8 | 691 |
Chrysler 354 Poly V8 | 691 - 700 |
Chrysler 354 Hemi | 720 |
Chrysler 392 Hemi | 740 |
DeSoto 276-341 Poly V8 | 675 |
DeSoto 276-291 Hemi | 630 |
DeSoto 330-345 Hemi | 670 |
Dodge 241-325 Poly V8 | 645 |
Dodge 241-270 Hemi | 580 |
Dodge 315-325 Hemi | 610 |
Dodge Viper V10 | 716 |
Dodge Viper V10 (1997) | 648 |
Dodge truck V10 | 816 - 836 |
Mopar Slant Six | 475 |
Mopar 277-301-318 Poly "A" V8 | 600+ (estimate) |
Mopar 273-318-340 "LA" V8 | 525 |
Mopar 360 "LA" | 550 |
Mopar 350-361-383-400 "B" V8 | 620 |
Mopar 413-426W-440 "RB" V8 | 670 |
Mopar Street Hemi | 765 |