motor mounting? - The 1947 - Present Chevrolet & GMC Truck Message Board Network

sgtjed · 12-10-2002, 11:17 PM

i have a 70 c10 that had a 6cyl with a 3spd standard in it. it was converted to a 327/350 short tail auto. well they left the engine mount stands in the original location and i am going to move the motor forward to the v8 location to give me more room at the rear of the motor.
is the drive shaft longer for the v8 than it is for the i6? it looks like it will fall out when i move the motor foward the 2 inches it needs to go.
also can i get rid of the 2 peice drive shaft and go to a one peice on the long bed truck?

Longhorn Man · 12-11-2002, 12:05 AM

Yes, you'll need to lengthen your drive shaft, this is probably why it was placed in the wrong location.
If you have a short bed, you'll need a 4 foot 10 inch long shaft with the dshort shaft TH350 mounted in its proper location.

sgtjed · 12-11-2002, 01:59 AM

i kinda figured that it was set back for the drive shaft length.
i have a long bed. what would the length be on a drive shaft for it? could i use a later model one peice on it,from a newer long bed? reason i am asking is when i get my 402 built i will have to locate the motor to the v8 mounting location for sure.

Longhorn Man · 12-11-2002, 02:06 AM

Most drive shaft places won't do it on a long bed.
There has been mixed opinons here about it too.
Some will say spend the $$, find a good shop, and go for it. (it would be over 6 feet....and most places say 6 foot i s the cut off)
If you have a shaft that is too long, it will sag ever so slightly...but when spinning at 3000 RPM (on the freeway) just a 1/1000 of an inch will be felt.
A shop that will do it would make it out of HUGE stock, and then you'll need cros member mods that can weaken the chassis....
I'd just stick with the 2 piece shaft, and get good drive line components.

crazy longhorn · 12-11-2002, 10:14 AM

stgjed, i wouldnt move the position of the eng till you install the BB.......or you may be doing the shaft twice! The difference tween the sb, & I6 position is right at 3 1/2". The BB falls somewhere between that, & uses different stands than the sb. I believe you can mount the sb on the BB stands, & it will slide it ahead about an inch from I6 location......but you can not use the sb stands to mount the BB , due to clearance problems with ex manifolds/headers. I have my sb mounted in i6 position to move some weight rearward, & the only downside that i can see is that the clearance is pretty tight on the HEI dist. When my HEI "bites the big one", I will opt to install a small cap MSD to resolve that issue. I agree with the other longhorn on the shaft......right at the 6ft line is about all the local shops will go, & they reccomend a 4 1/2- 5" dia shaft.........thats a lot of trimmin on the crossmember! As another thought, if you are going BB, you could opt for one of the super long 400 turbos & have a short shaft built. good luck.....crazy AL

sgtjed · 12-11-2002, 12:19 PM

cool thanks,i have the bb stands from my brothers 68. he took them out and put later model stands in when he did his front disk conversion.
now thats why the stands were welded in my other 70 i had that was originaly a 402 that someone put a sb 400 in. the stands were welded halfway between the holes for sb and i6 using the bb stands.
good info guys i think i will hold off and do this when i get my 402 finished and ready to go in.

12-10-2002, 11:17 PM	#1
sgtjed What if? Join Date: Oct 2002 Location: Choctaw,Oklahoma Posts: 649	motor mounting? i have a 70 c10 that had a 6cyl with a 3spd standard in it. it was converted to a 327/350 short tail auto. well they left the engine mount stands in the original location and i am going to move the motor forward to the v8 location to give me more room at the rear of the motor. is the drive shaft longer for the v8 than it is for the i6? it looks like it will fall out when i move the motor foward the 2 inches it needs to go. also can i get rid of the 2 peice drive shaft and go to a one peice on the long bed truck?

12-11-2002, 10:14 AM	#5
crazy longhorn Fabricate till you "puke" Join Date: Jun 2002 Location: Ill Posts: 9,403	stgjed, i wouldnt move the position of the eng till you install the BB.......or you may be doing the shaft twice! The difference tween the sb, & I6 position is right at 3 1/2". The BB falls somewhere between that, & uses different stands than the sb. I believe you can mount the sb on the BB stands, & it will slide it ahead about an inch from I6 location......but you can not use the sb stands to mount the BB , due to clearance problems with ex manifolds/headers. I have my sb mounted in i6 position to move some weight rearward, & the only downside that i can see is that the clearance is pretty tight on the HEI dist. When my HEI "bites the big one", I will opt to install a small cap MSD to resolve that issue. I agree with the other longhorn on the shaft......right at the 6ft line is about all the local shops will go, & they reccomend a 4 1/2- 5" dia shaft.........thats a lot of trimmin on the crossmember! As another thought, if you are going BB, you could opt for one of the super long 400 turbos & have a short shaft built. good luck.....crazy AL __________________ 69 longhorn,4" chop,3/5 drop, 1/2 ton suspension/disc brakes,1 1/2" body drop,steel tilt clip, 5.3/Edelbrock rpm intake/600 carb, Hooker streetrod shorties,2 1/2" exhaust/ H pipe/50's Flows , 6 spd Richmond trans,12 bolt/ 3.40 gears....

12-11-2002, 12:05 AM	#2
Longhorn Man its all about the +6 inches Join Date: Jan 2001 Location: Hilliard Ohio Posts: 2,693	Yes, you'll need to lengthen your drive shaft, this is probably why it was placed in the wrong location. If you have a short bed, you'll need a 4 foot 10 inch long shaft with the dshort shaft TH350 mounted in its proper location.

12-11-2002, 01:59 AM	#3
sgtjed What if? Join Date: Oct 2002 Location: Choctaw,Oklahoma Posts: 649	i kinda figured that it was set back for the drive shaft length. i have a long bed. what would the length be on a drive shaft for it? could i use a later model one peice on it,from a newer long bed? reason i am asking is when i get my 402 built i will have to locate the motor to the v8 mounting location for sure.

12-11-2002, 02:06 AM	#4
Longhorn Man its all about the +6 inches Join Date: Jan 2001 Location: Hilliard Ohio Posts: 2,693	Most drive shaft places won't do it on a long bed. There has been mixed opinons here about it too. Some will say spend the $$, find a good shop, and go for it. (it would be over 6 feet....and most places say 6 foot i s the cut off) If you have a shaft that is too long, it will sag ever so slightly...but when spinning at 3000 RPM (on the freeway) just a 1/1000 of an inch will be felt. A shop that will do it would make it out of HUGE stock, and then you'll need cros member mods that can weaken the chassis.... I'd just stick with the 2 piece shaft, and get good drive line components.

12-11-2002, 12:19 PM	#6
sgtjed What if? Join Date: Oct 2002 Location: Choctaw,Oklahoma Posts: 649	cool thanks,i have the bb stands from my brothers 68. he took them out and put later model stands in when he did his front disk conversion. now thats why the stands were welded in my other 70 i had that was originaly a 402 that someone put a sb 400 in. the stands were welded halfway between the holes for sb and i6 using the bb stands. good info guys i think i will hold off and do this when i get my 402 finished and ready to go in.



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