Ok, need to ask the brain trust about gearing. I am going from a stock stroke 440 to 505, the rest of the combination that will be the same from motor to motor- cnc stealths, indy dual plane, quick fuel 4150 1050an . new changes- going to howards cam flat tapppedt solid with 246 @50 duration, 615 lift with ras 1.6 rockers, tti step headers and tti 3 exhaust x or h pipe (havn't decided which). my question is- I now have 4.10s in the dana, will going to 3.73 help or hurt in the quarter mile? My local guru says with the new stroker there will be plenty of torq for the 3.73 and it will run better. Just want other thoughts, main event for this car is Dragweek if that puts it into context. let me know your thoughts.

No opinions?

I don't think it hurt et much.. I know a lot of guys who go from 4.10 to 4.30 and don't gain much.. you will get more MHP out of it though.

The 3.73 gear would probably run the same as the 4.10 but with less rpm. Your cam is abit mild compared to the rest of the combo.

Id want something in the 260/264 range for duration @ .050

I'd keep the 4.10, but since your cam is so mild for a 505" motor...the 3.73 probably wouldn't hurt the timeslip.

How much does the car weight? Lower gears should always ET better until you run out of RPM. Lower gears make a bigger difference in heavy cars and more of a difference in a stick car.
Back in the day I picked up a half second going from 4.1 to 4.88 gears in my 4 spd cuda.

My 63 Dodge N/SS car with a .274@.050"/670 roller ran the same with a 29.5 tall slick. 4.10 and 4.56 within .02
Doug

what size tire's ?
my car with 28x10.5's and 4.10s goes through traps at 7200

car is a 4 speed, 3580 pound 71 challenger, 28 inch tall slick. thanks for the responses. I will look at the cam again, just about to order it, was trying to keep the duration @50 as short as possible to keep the power band in the lower rpm range, for the heavy car. are my thoughts off here? how much bigger would you go? I want to stay with a flat tappet. I want to build this thing to make the 32 car, daily driver field in dragweek. I missed it this year with a best run of 12.09 can't go faster than 10.80 (i am a long way from that!) faster than 11:50 I will have to put a bar in it (but will if i need to). the cutoff this year was 11.90ish. thanks Cab, i like the idea of keeping the 4.10 and trying it out first. I hadn't really thought of changing the gear untill a couple of local guys talked to me about it.
thanks again

Your going to have fun with the new motor and the 4 speed Another easy way to cheat on changing the rear gear ratio is tire hieghts, much easier than changing the gears in a Dana 60 the longer stroke will make a lot more torque than the stock stroke will, capitalizing on it is the hard part I would put a set of real tall street tires on it for the street driving and then see if you can find some shorter slicks, wider also if you can fit them the Mustang 5.0 crowd probally has enough racers that the tire company make some short, wide drag slicks for stick shifts for that market do you know if your first gear ratio is the earlier 2:66 or the 1971 2:42 ratio? Just curious

I just read your post again. Your car will not run better with a 3.73 gear. The only question is how much slower will it run with the 3.73's.

With a 505 I too think you should be looking at 260 ish duration
an ultradyne grind from bullet cams 263/271 108 LSA would seem great.


Stay with the 4.10 for now.

If you want to go quicker put 4.56 or 4.88 gears in the car.

My combination for Drag Week daily driver: 520RB stroker, MCH ported stealth's, ported street dominator intake, 950HP carb, MP590 cam, 1.6 RAS SS rockers, 11.3 CR, 2" super comps, 3" full exhaust, 6Q hemi pan, 1/2" pickup, MP windage tray, HV melling pump, 10" dynamic converter, fully automatic torqueflite with billet front drum and ultimate sprag, 3.91 8 3/4, moser axles, 295/55 MT Drag radials, beat up 70RR chassis, dead stock front suspension with sway bar, group 27 battery in front, brass 26" radiator, SS springs and MP long drag shocks, 11" drums all around. 3860# at the line with the fat driver and helmet. We ran 118-120MPH all week and never touched the engine. Car will run 11.50 (or less) just about anytime (yeah, the chassis sucks, but I'd drive it anywhere).

My advice: go as big as you can on cubes, run a little more cam than you are currently thinking, stick with the 4:10 and run 26" slicks at the track and taller tires on the road and you should be fine at making the cut IF you can shift (really well).

You will get tired of the RPM's on the highway, even with taller tires. I think going to the 3:73's is a move in the wrong direction for performance.

If you want to spend some $$ and change something, consider getting a coarse spline OD cluster for the 833 and cut a gear out of your shift chores while helping the highway revs.

Scott

"If you want to spend some $$ and change something, consider getting a coarse spline OD cluster for the 833 and cut a gear out of your shift chores while helping the highway revs."


on the waiting list for the passon 5 speed (already sent deposit in) but who know's if it will be ready by next year. thanks Scott, (pitted next to you at Memphis and asked about the RAS rockers, I found a set of 1.6)

Cab had a good question about your low gear ratio. If you have the later model gearset with the 2.42 low gear it would be helpful to go to the earlier 2.65 low gear setup (which also comes with the OD cluster). Do you know which one you have?

Scott

yes I have the 265 first gear, think I will keep the 4.10 in for now and see how the new motor runs. But have decided to go with a little more duration on the cam (as many have advised), with an Engle kv-4 will be 256@.050 with total of .621 lift. thanks for all the suggestions. I really hope Passon gets the 5 speed out soon, or I may look into the gearvendors unit.