Hot Rod Forum banner

Th350 question

1.8K views 9 replies 2 participants last post by  runn141  
#1 ·
do they make H.D Planatarry Gearsets for a TH350K transmission? this is the 4 wheel drive versian of the TH350C it's out of an '88Blazer that had a 5.7L SBC bolted to the front of it, and we bolted a 4.3L V6 to it for use in an '83.5 wagoneer (midsize it orgionally had a 2.5L 4 banger) i was wondering if there was a way to switch the First gear from 3.07:1 to someware in the negiborhood of 4.something:1 or a little more realisticily 3.10:1 or so, and i was also wanting to know if there was a way to chainge the gear ratio of an NV242 T-case from 2.74:1 to someware around 3:1 like the old Dana 300 T-case :confused: please help
 
#2 ·
Jeeper426 said:
do they make H.D Planatarry Gearsets for a TH350K transmission? this is the 4 wheel drive versian of the TH350C it's out of an '88Blazer that had a 5.7L SBC bolted to the front of it, and we bolted a 4.3L V6 to it for use in an '83.5 wagoneer (midsize it orgionally had a 2.5L 4 banger) i was wondering if there was a way to switch the First gear from 3.07:1 to someware in the negiborhood of 4.something:1 or a little more realisticily 3.10:1 or so, and i was also wanting to know if there was a way to chainge the gear ratio of an NV242 T-case from 2.74:1 to someware around 3:1 like the old Dana 300 T-case :confused: please help
there never was a 350 turbo of any version lower than 2.52 1st gear ratio. the only thing you can do is get the lower planetary gear to convert 1st gear to 2.75. you can find it at tci.com
 
#4 ·
origionally it was a 4 banger attached to a Christler 4 spd, i was looking in the wrong column, when i was looking at the gearing O.O the transmission i had had someware around a 2.90 or something like that, it was the light duty transmission, we put in this TH350 that we had a stage 2 shift kit put in, and Waow big difference in both power and shifts that old transmission i guess had a loose band or something but i could hardly feal it shift between gears till it hit lockup, how much of a difference would a 2.75 gearset make? greater low end torque, or just a little more power off the line?
 
#5 ·
Jeeper426 said:
origionally it was a 4 banger attached to a Christler 4 spd, i was looking in the wrong column, when i was looking at the gearing O.O the transmission i had had someware around a 2.90 or something like that, it was the light duty transmission, we put in this TH350 that we had a stage 2 shift kit put in, and Waow big difference in both power and shifts that old transmission i guess had a loose band or something but i could hardly feal it shift between gears till it hit lockup, how much of a difference would a 2.75 gearset make? greater low end torque, or just a little more power off the line?
with 2.75 1st with 3.42 rear you get the same final drive as a stoch 2.52 1st with a 3.73 rear. thats the best example i can give. going with a non lockup converter will make a world of difference, you may not need the lower planetary. alot cheaper anyway
 
#6 ·
i have my factory 3.73 gears in the rear end, and i was considering stepping up to deeper 4.10's so basicly it wouldnt make much difference if i swapped to 4.10 from 3.73 with a 2.75 first gear? or would it try to "Jump" when i was in 4Lo and give it "a little too much" throttle? i'm trying to get all the Low end i can get out of the motor, we put a rather large cam for a V6 and we ended up Haveing to run a 4 barrel carb and i opted to run True Duel Exhaust just because it was the easyest thing to do, and we were in a hurry to get the truck out of the garage, as i said earlyer it origionally had a 2.5L Iron Duke Buic motor.... that i tried several times to blow up. and failed.... i opted to run Electric fans and we found a High Output alternator that somebody put into the blazer we yanked the tranny out of, it was an '88 Chevy K5 blazer with a 350SBC, i was told this was a desierable tranny because according to what i heard the clutches are bigger or something like that, the blazer supposidly had a "tow package" but my dad said that it didnt, because chevy liked to use the TH400 as there tow package, which is the transmission i wanted to use to begine with :sweat:
 
#7 ·
Jeeper426 said:
i have my factory 3.73 gears in the rear end, and i was considering stepping up to deeper 4.10's so basicly it wouldnt make much difference if i swapped to 4.10 from 3.73 with a 2.75 first gear? or would it try to "Jump" when i was in 4Lo and give it "a little too much" throttle? i'm trying to get all the Low end i can get out of the motor, we put a rather large cam for a V6 and we ended up Haveing to run a 4 barrel carb and i opted to run True Duel Exhaust just because it was the easyest thing to do, and we were in a hurry to get the truck out of the garage, as i said earlyer it origionally had a 2.5L Iron Duke Buic motor.... that i tried several times to blow up. and failed.... i opted to run Electric fans and we found a High Output alternator that somebody put into the blazer we yanked the tranny out of, it was an '88 Chevy K5 blazer with a 350SBC, i was told this was a desierable tranny because according to what i heard the clutches are bigger or something like that, the blazer supposidly had a "tow package" but my dad said that it didnt, because chevy liked to use the TH400 as there tow package, which is the transmission i wanted to use to begine with :sweat:
turbo 400s usually came in 3/4 ton and heavier and i wouldnt think it would make much difference. but i know this, 4.10 gears will get better mileage with 33 inch tires than a 3.73, my cousin said no but i got 4.10s with 31 inch tires,bulldog tranny i get 12 mpg he has 3.73 33 inch tires,bulldog tranny, and gets 9 mpg. so it might be better to 4.10 instead.
 
#8 · (Edited)
makes sence, and i'd be able to put a little more power to the ground as well, either 4.10 or 4.33.... oh the possabilitys, my dad told me about a truck he built when he was a kid, he got ahold of a set of Rockwell 2.5Ton axles that have the 7.something:1 ratios and he put them under a '79 Dodge i think he said it was a Power waggon, he said he couldnt run faster then 40 on the highway, but there wasnt anything that it wouldnt go through :sweat: i'm looking for a more highway-able versian of something like that, but i'm not rock crawling, i'm just out playing in the occasional mud hole, and climbing things ever' so often, you know the basic trail ride :thumbup:, i talked to my dad about the 4.10's and he said the'd be good, but i'd have to stay away from the expressway with it O.O he said it'd wind the engine too tight he estimated around 3500 currently i turn 2150 at 65mph on the highway... maybe i'll stick with 3.73... or go to a 3.88
if they make one like that
 
#9 ·
Jeeper426 said:
makes sence, and i'd be able to put a little more power to the ground as well, either 4.10 or 4.33.... oh the possabilitys, my dad told me about a truck he built when he was a kid, he got ahold of a set of Rockwell 2.5Ton axles that have the 7.something:1 ratios and he put them under a '79 Dodge i think he said it was a Power waggon, he said he couldnt run faster then 40 on the highway, but there wasnt anything that it wouldnt go through :sweat: i'm looking for a more highway-able versian of something like that, but i'm not rock crawling, i'm just out playing in the occasional mud hole, and climbing things ever' so often, you know the basic trail ride :thumbup:, i talked to my dad about the 4.10's and he said the'd be good, but i'd have to stay away from the expressway with it O.O he said it'd wind the engine too tight he estimated around 3500 currently i turn 2150 at 65mph on the highway... maybe i'll stick with 3.73... or go to a 3.88
if they make one like that
you ever watch powerblock tv on spike ? stacey david on trucks built almost the same thing, rockwell axles in a 1940 dodge power wagon he named it sgt. rock