GT/GA or GT/HA Question(s)

ccm399 · 03-25-2009, 08:32 AM

Hi all,

I wanted to take a quick second and thank the helpful members of this board. I have been E-mailing back and forth with some of you quite regularly and the advice has been GREAT.

After further review it looks like I need to make a small change in the class(es) I plan run and this rules out HA. So the car will be setup for CA - GA. I plan to run a 305, probably the 1980 305/180 that is GT factored at 250HP.

I understand the 305's like/need a lot of gear both in the trans and the rear end. Can any of the 305 guys shed a little light on this for me. I contacted the NHRA about a couple things one of which was the trans and they told me I need to run a 3 speed but do I need/want the 2.75 first gear of the TH350? Also, does a 6.00 or 6.20 gear sound about right for the rear end (with a 14.5 x 33 Hoosier).

I guess this would be a great time to ask what tire the 305 guys recommend too! I was thinking that particular Hoosier because it is the light weight carcass tire. Maybe I should look for a slightly smaller tire to reduce the amount of power needed to drive the tire? My reasoning was with all that starting line ration I would probably need a large contact patch to help traction (especially on marginal tracks). What about the radial slicks, they were not out in the larger sizes when I raced some years back. Any input on them?

As always thanks for the help!

Chris

03-25-2009, 08:32 AM	#5
ccm399 Junior Member Join Date: Jan 2009 Posts: 3 Likes: 0 Liked 0 Times in 0 Posts	Re: GT/GA or GT/HA Question(s) Hi all, I wanted to take a quick second and thank the helpful members of this board. I have been E-mailing back and forth with some of you quite regularly and the advice has been GREAT. After further review it looks like I need to make a small change in the class(es) I plan run and this rules out HA. So the car will be setup for CA - GA. I plan to run a 305, probably the 1980 305/180 that is GT factored at 250HP. I understand the 305's like/need a lot of gear both in the trans and the rear end. Can any of the 305 guys shed a little light on this for me. I contacted the NHRA about a couple things one of which was the trans and they told me I need to run a 3 speed but do I need/want the 2.75 first gear of the TH350? Also, does a 6.00 or 6.20 gear sound about right for the rear end (with a 14.5 x 33 Hoosier). I guess this would be a great time to ask what tire the 305 guys recommend too! I was thinking that particular Hoosier because it is the light weight carcass tire. Maybe I should look for a slightly smaller tire to reduce the amount of power needed to drive the tire? My reasoning was with all that starting line ration I would probably need a large contact patch to help traction (especially on marginal tracks). What about the radial slicks, they were not out in the larger sizes when I raced some years back. Any input on them? As always thanks for the help! Chris