i took a ride in my buddy's bull nose 351w yesterday, after he put a street fighter c6 trans in it. and the difference from being a standard then going to a built automatic was quite impressive. so now while my motor is is pieces i'm thinking about replacing my old 4 speed with an automatic. i was thinking something along the lines of a super street fighter c6. what i was wondering is what rear end gears do i need to be able to do smokey burnouts and still hit 100 mph pretty quick. my 4 speed will burn em off in every gear and wrap the speedo extremely quick and ask for another gear. its registered for 100 and i can bring it up to about twenty before i get back out of it due to it screaming at me. i have a 74 highboy 428 fe (mildly built) with 4.10 rear end gears, 33 inch tires. so what do you guys think would be a good gear choice? i don't care about gas mileage what so ever. it runs on 116 race gas. the truck is just to remind my friends that there's no replacement for displacement, and to have a good time in.

oops almost forgot i will not run my motor past 5500rpms. my dad and brother do it, and say its okay. but its not theres to fix when it decides to come apart.

 

Depends on what you want? my all time best was 11.747 @ like 119 MPH in the quarter with the 428 in a '64 SB F100 with a 1/1 final, on 31/13/15 slicks @5500 RPM. All real steel 4,040# with me & the fuel cell. that was a ONE PASS run with a stern "DO NOT do that again, or you WILL NOT be allowed back!" Apparently you need to have things like NOMEX, and cages, and fuel shut-offs, and, and, and...... oh well 12's were fun too! Luckily they let me stay & play, although the Safety's got a lot more thorough!!!" title="Evil Grin" class="inlineimg" border="0">

Yours will weigh more, have more drag, but you should be able to smoke tires from 3.50's to 4.56s. things like tire width will change more than a slight change in gears, up or down. I'd stay with the 4.11's. with 33's or even 35's I think they give the best of both worlds and get you into the 120 MPH range by your 5500 rpm (friction & drag depending)

How fast you get there is a whole 'nother Animal! Torque torque torque!

 

what diameter and type of tire are you running? 4.10's are short if youre anything close to stock size and wanting to run over 100 mph.

 

33 all terrains

 

it sounds like you should probably consider running something a lot more traction oriented.

 

ive tried four diff sets of tires so far the best are some m/t drag tires my buddy let me try. but i cant run those, it is illegal.

 

these babies are dot approved, though wouldn't be good on a daily...
M&H Racemaster Cheater Drag Race Slicks MHD11 - SummitRacing.com

if you drive on the street too, the ET radials or something similar would be a better option.
or radial t/a's or even sportsman s/r's... depending on balance of street vs track.

anyway for gears it sounds like you are pretty close to what you want to be at, right? switch to a taller gear and its going to hurt acceleration...but give more speed on the top end.

 

I wouldn't think much lower than 4.10s that you already have would be in order. Mine is on 35s and has 4.10s and It runs I think about 2300+ at 60 mph, so that should put you at at around 4000+ at 100 mph, with 35s and a C6 but you have 33s so you would spin faster, but go to like a 4.56 gear and gain 10% so roughly 4500 rpm at 100 mph, maybe more with smaller tires.

Now go to 4.88s and gain 20% so you are 5000 rpm at 100, Roughly. That might be your answer, and with 4.88s you will be the tire salesman's best friend.

 

with the torque curve of a big block, though, and a manual transmission, shorter gears aren't necessarily gonna make the truck faster. They will definitely make you shift more, though. And every shift makes you slower.