I 6 to v 8 454???

[2005z71chevy]

hey guys iv got an 81 half ton 2wd it has a th 350 tranny that is in good shap and had an in line 6 for the motor. whats involved in swapping to a 454 would a th 350 hold up to it saying its in good shal/Low miles. and as far as motor mounts what would have to be done there. i know the cooling system has to get up graded but i really just want to know what to do with motor mounts and the th 350.would the tranny line up to the 454 or would i have to get a different bell housing. i would get a 400 tranny but iv heard the th350 is a beter choice for a street truck because it shifts differently than the 400. I could use a little help. thanks guys this sight has been really help full in the past. o ya sorry that this truck only has one axle and no transfer case....they must have fallen off the truck a while back

 

[diesel4me]

Not a problem...

The TH350 will bolt right up to a 454..only thing to watch is make sure the 454's flex plate is the correct one for a 454,you cant use any other one,because its externally balanced with weights (up until 85 or so anyway)...also,make sure it has BOTH bolt patterns for a TH350 torque converter, AND a TH400..some only came drilled for a TH400 tranny..other than that,it will work..

I've run a few TH350's behind 454's that used to be 6 bangers and small blocks..sure,a 454 WILL shred a TH350 if you beat the snot out of it,but driven normally ,on street use I doubt any problems will arise...but a TH400 IS more desirable,they hold up better under the high torque of a big block..but GM used Powerglides on big blocks too though,as well as TH350's,so take that into consideration!..

The 454 will need the brackets that bolt to the block for the motor mounts ,the 6 cylinder ones only fit sixes.(small block brackets will fif a 454 and work too)....the pads on the truck's frame will have to be moved to the other set of holes already drilled there..other than needing a bigger radiator,new exhaust,and a detent cable bracket for the TH350,thats about it for modifications...
..be aware most 6 banger trucks had low rear axle gears,like 4.10's or 4.56's..they will make a 454 feel even bigger!..my 79 C10 takes off like a dragster now that the 250 that died has been replaced by a fire breathing 305!. yeah,I know,but its a lot faster than it was before at red lights!..

 

[2005z71chevy]

A Mass. hole helping a fellow Mass. hole..ha... Thanks for the help with your post it was exactly what i was looking for