Over the last 3 yrs I have changed my car considerably. It was a 68 Notchback, backhalved, PG, 8 3/4, 413ci smallblock, W2 heads, 950 Holley, roller cam, JE pistons with 6.4 rods, weight 2940. The cars best in that configuration was a 6.32 1/8mi. Things I have done include an aftermarket 9", alum driveshaft, built a 413ci blower motor, and replaced stock front suspension with my design K member, Lamb struts and R&P steering. I was concerned about increase in weight primarily because of that heavy blower however after I scaled it I was surprised that I lost 40lbs on the front. The car now weighs 2900 with 50.03% on the rear. I would have had more on the rear but I moved the engine forward 2 inches and raised it 2 inches off the stock frame rails instead of cutting and reworking the trans cross member. I have not dynoed it and I haven't had it on the track because I'm still playing with the Holley bugcatcher injection so I don't have any idea how it will perform. I guess my question is typically where in the performance spectrum is it usually required for the weight bias to move to the front rather than the rear?

When it wheelstands higher and/or harder than you want it to. Moving the engine out and up 2" is a big move. You may wish you had lowered it. 50% is nice though. Ladder bar or 4 link?

Depends on power to weight. Mine is 1810F/1535R, (54.5%F). Some where around 900hp. Foot brake only on 10.5W. Had to revalue the front shocks tighter. It rides the wheelie bars aprox 60ft. Has been 1.240. If it has power 50/50 is to light on the nose.
Doug

900 HP- SHEESH!!
IF Your ever going to be in East or Central Texas, i would like us to get together and buy your lunch/pick your brain.

At 700 hp, 3400 lbs- what would you like to see on weight bias ( 65 b body)?

At 650 hp, 2850 lbs - what weight bias do you like to see ( 72 duster) ?

On one extreme, you have a car that wants to climb the ring gear, hit the bars hard and unload the rear tires. On the other, it has no pitch rotation or weight transfer and spins the tires. Balance is just part of the equation. A hundred other things are part of it as well. And there are things one can do to compensate or adjust for less than optimum bias. Some cars are not that sensitive. Others - big power, small radial tire - can go from dragging the bumper to blowing the tires off just by moving 10 or 15# around in the car

What SLR? Tire size and type, Suspension type? All make a difference. We are trying to attempt to get the car to make nearly a complete revolution of the tire before the front tire comes off the ground. Haven't accomplished that yet but getting close. The 60 ft still dropping and consistency getting better. My bet is the B body at that weight and power won't be to picky, but the A body??? You can try 50/50 but I'd have the front travel tied up and a pair of wheelie bars.
Doug

CMcAllister/dvw, it sounds mush worse than it is. Due to my inept engineering after I had the struts installed and stuck the engine in I had a major problem in that the front of the car sat much too low. I raised the front of the engine 2 inches and it still was too low. I ended up having to section 1 1/2" and lengthen the sump on my rear sump oil pan to be able to slide a upright 2X4 under the pan. It all worked out good and the crank centerline ended up 13.5" off the floor. The lowest part of my K- frame is 4 3/4" above the floor. I have a glass front end on the car sans bumper and I recently added an air dam to it which is just above 3" high. I made sure I have 3" clearance to meet the rules. I love the way the car sits and the front is low. The car is a ladder bar setup and that is something else I changed on this makeover. The previous ladder bars were really old school and had no adjustment unless you took them off the car. I replaced them with more modern bars with adjustment. Concerning weight bias I do have a little adjustment in that I have a 100 lb weight in the rear that I installed years ago to make a certain weight. It is bolted in so I can easily change to a front bias of 52/48 as a second condition and then play with adjustments in between.

Wheelie bars? Radials?

No wheelie bars yet, I've always been able to control wheelies to around 6" to 8" so It will be interesting with this new config. New slicks are 12.5" wide Phoenix, Goodyear quit building my favorite size so this is also a new item.