Well I need to figure out what gears to get. This is a street truck but building to have fun. Not my DD but will see a good bit highway cruising. I have a set of new 373's that i was going to use but am wondering if i needed 410, 390? I will be running a 28" tires. I've done so much reading my head hurts! not sure what size stall yet(need to contact Circle D still). Currently have a 60e but will be swapping to 80e when the turbo goes on. Oh and i already have a truetrac to install also.

 

4.10s will be best for performance, worst for economy.

 

Yea I know that but I don't want to regret not going with enough gear. Thought about 456's but i think that's a lil much. I figure settling for 430s should be manageable on the highway. As long as i can manage 2200ish @ 70 mph.

 

i ran 488s with a turbo 4.8 before

430s is a good place to end up

 

488s was with a t56 to my knowledge. The gearing number is irrelevant without taking into account the transmission ratios.

 

1:1 is 1:1 in any trans, since we race in high gear as soon as possible it is the same

also as i stated 430s is a good place to be

 

You still have to get to high gear, which is the majority of the time spent going down the track.

Not to mention he says it will be doing a lot of highway cruising. 28" tires and 4.30s 4l80 will be running probably 3k rpms at a reasonable speed. Guzzling more gas than me on liquor last nite. All factors need to be taken into accounting, including the fact that not every truck is a race truck driving on the street.

 

2700 rpms at 70 mph using a 28" tire, swap to a 30" and be fine using a 4l80 on street

 

Yes, i should have included that 28" will be track tire. Will run 30ish on street. I know 410, 390, or 373 would be a better street friendly gear but this is not a DD. I might just have to cruise around at 60 mph. I think i will swing for 430's possibly 410's. What would you recommend GMCtrk??

 

4.10s or 4.30s as George suggested, in that situation.

Even with the steep gear you should still be able to get 15-17 mpg highway, assuming gasoline