Help

Ron Scott · 12-06-2007, 02:35 PM

I'm in the process of sorting out a newly built 1986 Firebird for SS Gt class. Having been away from class racing for several years I would like to ask for some help.
The car is powered by a 250 horse sbc with a 2.08 first gear glide, a 5:43 rear gear and 29.5 Mickeys. It weights 3280 with driver. The best to date is an 11.0 -119 mph,1.56 short time. Since my last outing I have improved the converter to 5200 stall, added a victor jr.and new carb and found a suspension proplem. I have been told that low horse power cars need wheel speed in the first half of the quarter, with that said I am planning to change to a 5:83 or is this gear to much. I presently run through at 7200. any suggestions would be very helpful.

Dave Goob Cook · 12-06-2007, 03:36 PM

If your stall "improvement" was more stall, you should try it before you buy more gear, if you went the other way, I'd say the change sounds reasonable.

Good MPH, that thing is hauling.....

tim worner · 12-11-2007, 07:00 PM

I run the same combo and use a 6:00 rear gear and go thru around 8500. ATI makes a great convertor for that combo Call Cris and tell him you need one just like mine. I also use the short mickey. You might want to switch to radial.

Jeff Goss · 12-11-2007, 10:19 PM

What Tim said. He knows the combo.

You have enough tire. The radial is worth about .09-mainly because it wont grow at speed.

Stall should be 6000-6200. 6.00 gear is good. Should be 8000-8100 at the traps-higher if you really want to buzz the motor. 2.08 first gear is good. I ran a 1.98.

Work out that suspension. Not sure what you currently run for a rear end, but there are great products out there to get it to hook. You shouldn't spin the tire at all-you aren't making any torque.

Good luck!

Jeff
6990 SS/MA

Ron Scott · 12-12-2007, 06:18 PM

Thanks for the input.
I am currently running 5.43 gear with ladder bars and coil overs.
Don't realy want to buzz motor over 76-78 but maybe its to late to worry about that.

Brad Potter · 12-12-2007, 09:59 PM

Which 250hp combo are you running?

Ron Scott · 12-13-2007, 03:23 PM

441 heads, I may be off on the 250 horse in years passed thats what it was.

Greg Hill · 12-13-2007, 07:27 PM

441 head is from a 69 350-255 which is rated at 294 or 295 in GT.
Greg

Brad Potter · 12-13-2007, 08:41 PM

The classification guide still lists that engine at 290hp.

bob d · 12-14-2007, 10:13 AM

you back in the Seat "Fire Chief Scott"? or is this Davids car?

12-06-2007, 02:35 PM	#1
Ron Scott Junior Member Join Date: Nov 2007 Location: Massachusetts Posts: 5 Likes: 0 Liked 0 Times in 0 Posts	Help I'm in the process of sorting out a newly built 1986 Firebird for SS Gt class. Having been away from class racing for several years I would like to ask for some help. The car is powered by a 250 horse sbc with a 2.08 first gear glide, a 5:43 rear gear and 29.5 Mickeys. It weights 3280 with driver. The best to date is an 11.0 -119 mph,1.56 short time. Since my last outing I have improved the converter to 5200 stall, added a victor jr.and new carb and found a suspension proplem. I have been told that low horse power cars need wheel speed in the first half of the quarter, with that said I am planning to change to a 5:83 or is this gear to much. I presently run through at 7200. any suggestions would be very helpful.

12-06-2007, 03:36 PM	#2
Dave Goob Cook Member Join Date: Dec 2006 Location: Indy Posts: 422 Likes: 0 Liked 0 Times in 0 Posts	Re: Help If your stall "improvement" was more stall, you should try it before you buy more gear, if you went the other way, I'd say the change sounds reasonable. Good MPH, that thing is hauling.....

12-11-2007, 07:00 PM	#3
tim worner Senior Member Join Date: Jan 2002 Location: duncannon Posts: 837 Likes: 14 Liked 126 Times in 20 Posts	Re: Help I run the same combo and use a 6:00 rear gear and go thru around 8500. ATI makes a great convertor for that combo Call Cris and tell him you need one just like mine. I also use the short mickey. You might want to switch to radial. __________________ Tim Worner SS 1747

12-11-2007, 10:19 PM	#4
Jeff Goss Member Join Date: Nov 2001 Location: Burlington, WA Posts: 361 Likes: 1 Liked 0 Times in 0 Posts	Re: Help What Tim said. He knows the combo. You have enough tire. The radial is worth about .09-mainly because it wont grow at speed. Stall should be 6000-6200. 6.00 gear is good. Should be 8000-8100 at the traps-higher if you really want to buzz the motor. 2.08 first gear is good. I ran a 1.98. Work out that suspension. Not sure what you currently run for a rear end, but there are great products out there to get it to hook. You shouldn't spin the tire at all-you aren't making any torque. Good luck! Jeff 6990 SS/MA

12-12-2007, 06:18 PM	#5
Ron Scott Junior Member Join Date: Nov 2007 Location: Massachusetts Posts: 5 Likes: 0 Liked 0 Times in 0 Posts	Re: Help Thanks for the input. I am currently running 5.43 gear with ladder bars and coil overs. Don't realy want to buzz motor over 76-78 but maybe its to late to worry about that.

12-12-2007, 09:59 PM	#6
Brad Potter Junior Member Join Date: Aug 2004 Posts: 11 Likes: 0 Liked 0 Times in 0 Posts	Re: Help Which 250hp combo are you running?

12-13-2007, 03:23 PM	#7
Ron Scott Junior Member Join Date: Nov 2007 Location: Massachusetts Posts: 5 Likes: 0 Liked 0 Times in 0 Posts	Re: Help 441 heads, I may be off on the 250 horse in years passed thats what it was.

12-13-2007, 07:27 PM	#8
Greg Hill VIP Member Join Date: May 2006 Location: Louisville , KY Posts: 1,995 Likes: 68 Liked 279 Times in 68 Posts	Re: Help 441 head is from a 69 350-255 which is rated at 294 or 295 in GT. Greg

12-13-2007, 08:41 PM	#9
Brad Potter Junior Member Join Date: Aug 2004 Posts: 11 Likes: 0 Liked 0 Times in 0 Posts	Re: Help The classification guide still lists that engine at 290hp.

12-14-2007, 10:13 AM	#10
bob d Junior Member Join Date: Dec 2007 Posts: 4 Likes: 0 Liked 0 Times in 0 Posts	Re: Help you back in the Seat "Fire Chief Scott"? or is this Davids car?