I also posted this in the gear section, but after i thought it might be more appropriate here. Any help is appriciated, I will answer any questions i can. Thank You.
I am going to wait one more track day till i pull the trigger on gears, but i just wanted to see what some of you thought, if i am on the right track. As of now i have a strange 12 bolt with 3.73s. I really havent had much track time with the new 402, but i went last weekend and after watching the video i am just shifting to 4th shortly before the traps when on motor. The track wasnt good to make a n20 pass.(150 SHOT) I know that 4.10s would be perfect on motor, but on the jug i dont know. I can spin to 6800-7000. I also need some new dot tires for some of the classes i end up running in. I was figuring if the Hoosier QTPs in a 27/15 were good that would put my effective gear ratio at like 3.93 and at 6800 that is good for a 133 trap. So far the best i have trapped on motor is 117, but that was short shifting out of first and second. I know that it has a 120+ trap in it on motor, just havent found it yet. I dont want to put a 28" tire on as i absolutely refuse to roll my fenders, i spent the whole last summer and a ton of $$ on the body to make it perfect. Will the 27's work with that gear and will they fit without mods??

 

i believe wat i calculated with 3.70's and a 27" tire the car will be at lik 140mph at the top of first turning 6800 rpm. id say with a 150 shot you 3.73s and a 27" tire might be right on

 

what i am wondering is if i can pull it off with the 4.10s?? I know they would be better than the 3.73s on motor. I am a m6 as well.

 

well 3.73s wont put you where you want you be at 144mph at the top of 4th but 4.10s might not allow you enough room. if you trapping 117 on motor not givin it its all so it depends somethin lik 3.90s might be wat you need with a 27" tire. on a 150 shot you may possibly trap more then 133mph

 

yea, that is the variable i dont know know. I should find out on june 6th. I wont do anything till then. I want to see how it runs on spray. But i also want it to run as best it can on motor. I thought bout the 3.90s, but i dont think they would make that much diff over the 3.73s.

 

i think you need to run it all out on motor see wat it traps then and then decide it wouldnt be cool if you went with 4.10s and ran out of gear on spray. but 3.90s probably wont put you at the very top of 4th

 

That is what the plan is. I will get to run a 26" slick in june, and this track usually preps really well for this event. I should get some good baseline times with the 3.73s. What i was figuring is that a 27" tire might just get me the best of both worlds with the 4.10s. But i want to wait and see how it does on motor, and spray with the gears i have now. Will the 27" tire fit without modification??. I am not against getting rid of the bump stops, but i will not roll my fender, or bfh the inner fenderwell, and def no cutting my brand new G.M. facsia.

 

I'm running 4.11s with a 27" Hoosier. Don't have any fitment issues with them

 

thats what i wanted to know, do they hook??

 

anybody else??

 

Don't know because my suspension wasn't adjusted last time I went to the track. It did go a 1.55 60ft but unloaded the tires and upset the car before the 60ft. Once I get the pinion angle set and the LCAs adjusted hopefully it'll go some 40s

 

I would be happy with consistant 1.55 60's. I generally run that or on a track nite like last sat my best was a 1.68.

 

I guess we will have to see how she runs at the track with the current gears, just made a data log tonite, 4th gear 6500rpm =136mph. Still another almost 500 rpm left. I dont think i will trap that high, even on spray.

 

i was about to chime in that i think you could get upper 13x mph out of that setup if going up to 6800-7000 but with that small cam does it still pull that high ? i was thinking it would peak around 6000-6200.

 

yes it pulls hard all the way to 7000. On the dyno sheet it peaks around 6300-6450. It falls very slowly though. And that was with a crappy *** tune that had way way too much timing and a afr at wot of 11.0-10.9 on motor only. She runs like a bitch now.