4-link dragster rear gear ratio/tire size

[jed5161]

Wondering what you guys out there are running for rear gear ratios and tire sizes. heres what i got:

250" 4 link dragster 1800 lbs
605 Ci BBC around 1050-1100 hp no bottle
1.80 glide
4.10
33.5x16.5x16 weld beadlocks/mickey thompson tire

I've been running low 4.80's 140-142 mph 1/8th mile. I've noticed mojority of guys run 34.5's. i swapped a set of hoosier 34.5's onto our car thinkin it may help. Well i ended fallin off to 4.88 to 4.90 range and 136-137 mph. The car feels as if its launching harder and it pulls the front end better with same 60 ft, but looses everything down track.

[gnsrule]

whats the MPH thru the traps ?

[jed5161]

we run all 1/8th mile exept for maybe two races a year. (a 10k race and et finals) With 33.5's we do 140-142 mph. with 34.5's it fell off to 136-138 mph range. im not sure RPM wise what we do on the 1/8th. I'm guessing 6600-6800. I know for sure on quarter mile with 33.5's its 7100 through the traps. We shift at 7200-7400 and launch at 5600. 6000-6200 outta the convertor

[gnsrule]

My bad..I ment to ask what RPM. Guessing on that would leave only guess's on what you need for a gear swap.

[hammertime]

I've used both the 4.10 and 4.30 gear along with both the 33.5 and 34.5 in tire. Some cars like the 34.5 others do not. I assune 1800lbs is a empty car no driver ? Whats it weigh with driver ?

Id run a 4.10 and a 33.5 hoosier on the beadlocks if it were mine. 34.5 and the beadlock are to much for that et of a car, its lugging it down which is why your seeing the slower et/mph. If you do decide to go back the 33.5 tire, Avoid the 3185 MT.. that tire has major issues in dewy/cold weather. Converter comes into play a lot here also you have to tweak converters towards the big tire if you want to stay with it. Was the hoosier new ?

[jed5161]

car is right at 2000 with driver. we put the mickey 33.5's back on the car. The hoosiers were not new. they were ran on our pro mod car for a short 6-8 race season and then our spitzer Pro Top Outlaw dragster for about half season before going to a 36" top fuel tire.

Were changing from conventional heads (profiler cnc ported 365's) to either big chiefs or big dukes. Debating on shooting it with 200-300 shot of nitrous.

I'd like to be in low 4.70's high 4.60s on motor.

[hammertime]

car is right at 2000 with driver. we put the mickey 33.5's back on the car. The hoosiers were not new. they were ran on our pro mod car for a short 6-8 race season and then our spitzer Pro Top Outlaw dragster for about half season before going to a 36" top fuel tire.

Were changing from conventional heads (profiler cnc ported 365's) to either big chiefs or big dukes. Debating on shooting it with 200-300 shot of nitrous.

I'd like to be in low 4.70's high 4.60s on motor.

I dont think you need the dukes to get there, maybe some tweaking on what you have now. The profiler head seems to be a decent head, if it were mine Id loose the converter up a touch 6400-6500ish. You are launching very high also, which might be hurting more then helping.
My motor makes peak 1013hp but avg 985 and runs low 4.7's all day @ almost the same weight as yours, I launch @ 4200 shift on time @ 6700rpms, cross 1/4 @ 7100. My converter is 6800 9" spragless coan, its much more agressive and faster with my 6400 stall stuff though.