Have the car running a little better. A couple weeks ago ran the car in the shop on jack stands for 3 miles to break in the NOS 3.23 ratio ring and pinion gears. Set the front wheel toe-in with a tape measure to 3/16 inch. Have appt for wheel alignment next week.
Oil pressure checked out at 30 psi at idle, and 65 psi max. That is with Melling std volume/pressure oil pump. New cam bearings really make the difference for good oil pressure at idle.
Next worked on the vehicle ride height. Noticed that on 1968-70 satellite and chargers you can see the front spring bolt for the leaf springs (the bolt center is below the bottom flange of the qtr panel); as compared the E-body bolt which is buried up into the unibody.
So purchased mopar super stock spring hangers; they have extra material for the “shorter” SS springs, and the flange widths are considerably thicker than stock. Drilled new bolt holes as low as possible, leaving ¾ inch of material below the finished hole, just like the factory cut SS holes. Cut off the excess, painted, and bolted them in. Also noticed the heavy duty leaf springs I had purchased had the extra leafs for right rear traction, but they also had much more of the main leaf unsupported, which let the spring sag and arc the wrong way…maybe due to the extra 140 lb of rear weight I added to the trunk with the battery back there.
So cut the eyes of each end of the original main leaf, and added the shorted leafs in-place of the second leaf on the heavy duty springs….so have 2 leafs running full length. The ride will be stiffer, and if too stiff it will affect the leafs ability to flex and apply traction. Having 2 full length leafs worked out real well on the 340 Duster I had years ago. I looked at a ’68 satellite wagon in the parts yard. It had 2 leafs full length to the front spring hanger, and the second leaf stopped about 8 inches short of full length in the back. So if the challenger is too stiff over bumps I may cut the back 6-8 inches off the second leaf.
The leaf springs have some arch overall, and fairly flat at the front. I reset the torsion bars for the front of the car ½ inch nose up to help clearance with the exhaust headers. I gained 1 inch ride height doing all this. Doesn’t seem like much but I started with only a little over 4 inches, so much better IMO.
For tires installed 235/60-R15 Mickey Thompson sportsman; ordered them from Summit racing. Mounted on 15x7 Basset racing wheels, they offer DOT approved rim thickness so went with that. Need 45 degree lug nuts to go with the wheels, also need 1 inch socket to fit the lug nuts.
Next problem, the engine vacuum at idle is only about 8 inches vacuum. I asked questions, and was told to up the ignition advance at idle; I was told this helps engine vacuum and gives a nice ‘snap’ to engine acceleration. So now have it set at 16* BTC at idle, with 36* total at 2400 rpm. The extra advance at idle helped to stop the engine after-running when shutting the engine down, even though idle rpm was only 750 rpm was having some after running. Looked into engine vacuum loss at higher elevations above sea level; internet search said loose 1 inch for every 1000 foot elevation. So I’m down 5 inches at my altitude. The power brakes sort of work. I’m concerned of the wife or boy driving the car, so ordered a custom cam from Lunati, with 112 lobe separation.
Studied up on the vacuum problem by re-reading my books by David Vizard. The problem is the increased rocker arm ratio that goes with the magnum style cylinder heads…this ratio increase messes with the valve overlap, and makes the cam more ‘cammy’. Going from 1.5 to 1.6 rocker ratio increased the valve overlap area ‘triangle’ by 8%. The 50 degrees overlap has not changed, but the area within the triangle has increase because the valves are being opened faster with the 1.6 rocker arms.
I did not want to try a mopar 904 cam lobe combined with 1.6 rocker ratio, so instead went with Lunati lobe H220, mid-lift lobe family, very streetable…wont’ be hard on valve train. Also added the extra hard nitride treatment to the cam lobes. They said the cam will take about 3 weeks.
The cam in the car now is Comp 270H, sort of a mild version of Engle K56. Lots of folks running the 270H with 1.5 rocker ratio and very happy with performance and valve train life.
Comparing specs for the 270H (1.5 rocker ratio) vs H220 (1.6 rocker ratio), both single pattern cams:
270H: 270*seat, 224* @.05 lift, 135*@.20 lift, .470 valve lift, 110 LSA, 50*overlap
H220: 270* seat, 223*@.05 lift, 137*@.20 lift, .496 valve lift, 112 LSA, 46*overlap
Note the 137*@.2 is real close to the 138* that a voodoo 904 lobe #VH43 has, so the H220 with 1.6 rocker will be close to a 904 lobe/1.5 rocker.
Right now with the 1.6 rocker ratio, the 270H has 227*@.05, and acts like 54*overlap, so ordered the H220 with wider lobe separation. According to Vizard the 2*wider LSA will make up for the rocker ratio increase, and recover the lost vacuum. Hope it all works out as intended.
The first photo is the front hanger for leaf springs. On the left is super stock hanger, in the middle is the modified SS hanger, and on right is oem E-body hanger. The next pics are the car out side under its own power for the first time in 6 years. I drove it around a little…it wants to go for sure. Next week with the wheels aligned, I’ll check O2 sensor readings then run the car over the mountain passes to seat the piston rings while waiting for the new cam.
