Rear end ratio

Hi all, im trying to get into the 8.90's with my front engine dragster. I have the ability to run up to 100hp of nitrous, but cash is tight at the moment and im looking to see what i can change to help me to achieve this goal without using nitrous. I know I dont have a lot to pick up by changine rear end ratio, but im wondering how much i could pick up, if any. I have 3.89 gears currently, and im wondering if 4.11 gears would be better in my case. I still have some more to come from the motor i think, as weve not really changed tried anything with the jetting (although the plugs look great) and i think we may be able to use a bit more advance yet. I also have a new shifter as the old one was worn out.

Current personal best run:
60 ft : 1.3588
330 ft : 3.8326
1/8 ET : 5.9740
1/8 MPH : 114.04
1000ft : 7.7941
1/4 ET : 9.4514
1/4 MPH : 139.72

Current Build
Stock 460 block bored +60
4.300 crank
6.700 rods
Kb 403 pistons
(these are from a budget ebay stroker kit... i know these things arent the best but for now they are what i have managed to get and im limiting my expectations based off this... i will be keeping the RPM's below 6500 - the kit has been balanced)
Edelbrock Performer RPM CJ heads
Edelbrock Victor manifold (non dominator)
Cam research 245/255, 590/615, 110 Lsa Solid Flat Tappet Cam, bedded in on their machine.
950 Holley Carb
Crane Pro Billet dizzy
Crane HI-6N Ignition box (with rev limiter)
Crane LX92 coil
Stage 1 oil pump from Paul Kane (MANY MANY THANKS)
SFI Flexplate, SFI Damper
Fueling is from a Barry Grant 280 GPH pump
3500 Stall torque convertor

Ford 9 inch with Moser 33 spline shafts, moser spool, strange carrier and 3.89 pro gears.

33.5 x 15 Rear Slicks

Estimated weight of car and driver 1800-1900lbs

How many RPM are you turning it now? What is the max RPM you are wanting to turn it?

On a good slide rule.... you would need about 525 hp @ 1900 lbs to make an 8 second run.

Cale that sure seems like an awfully smallish cam for a stroker engine, I think he is at his limits now....


Cam research 245/255, 590/615, 110 Lsa Solid Flat Tappet Cam



The cam is a baby


Randy

Good point... hadn't read that far! My bad!

Looks like he will need to upgrade the top end valve train a little.

Either way... he needs to hit the 525 or 550 mark to have enough to safely get into the 8 second zone at 1900 lbs.

Yeah, Im saving up for a roller cam setup (once my wedding is out the way). When the time comes im looking for a still relatively small cam, probably around 650 lift, max 700. For the cam, lifters, springs etc i need to save around $2000 to get one in the UK. Im looking at hitting it with a max of 100hp of nitrous just to top up in the meantime - that should be enough to see the 8.90's yeah? I think theres still maybe a bit more to come from the car yet. I had figured on mid 9's without the nitrous, so im right on target for that. Im looking to spin no more than 6300 at the top end, which I had figured was towards 160 mph with my current rear gear / tyre / top gear ratio. Im currently pushing just shy of 140 at the top end which puts me at around 5500 rpm. My shift light comes on at 5500 and that seems to come on between 1000ft and the full quarter in top gear.

When you go to purchase... let me know. I deal a lot in overseas stuff and I could probably save you some $$ on shipping and so on.

I think you are on the right track.

1900 lbs. seems a little heavy for a FED. What lenth wheel base are you running?

If the engine is running out of rpm with a 3.89, a 4.11 will slow you down. I would try a 3.70 or even 3.50 at 1900 pounds. As already said, more cam!

Its 186 inch wheel base, but is mild steel not chromoly. The car also has a (small) cooling system, and in some ways is probably a little overbuilt.

Looking to change to a glide for next year - looking to spec a cam and torque convertor to suit. Want to try and keep the revs certainly less than 6500, preferably shifting at 6000 rpm.