another engine swap question.....need som expertise - The 1947 - Present Chevrolet & GMC Truck Message Board Network

dubie · 03-16-2003, 10:13 AM

I am pulling the inline 6 out of the 72 this morning along with the 3 speed tranny. My question is this...... If I was to get the V8 mounts, move them up to the proper spot and put my 350 there, will I have problems hooking up my driveshaft and shift linkages? I was speaking with a very wise mechanic last night and he figes that it's only about 3/4" that it will move up and there shouldn't be any problems with this. I always thought that you would need a longer driveshaft to do this.
I could realy use your guys help on this because if i can put the 350 up farther so the HEI will clear the firewall some more, then I'm all for it. I just don't want to get into a whole bunch more work here.

Many thanks

crazy longhorn · 03-16-2003, 10:28 AM

Your engine/ trans will move foward 3 1/2"(plus or minus 1/8") from I 6 to sb V8 position, so the front half of the d shaft will be that much too short. you will also need to replace the bell crossmember, or just run an auto crossmember under the stick trans(I6, & V8 bell crossmembers are different).Im not sure how that will affect the column linkage,as i ran a floor shifter in my stick trucks. good luck,crazyL

Johns70 · 03-16-2003, 12:36 PM

the saginaw 3-speed and bellhousing are the same leght as a th-350 long shaft tranny, hope this helps in your qeust

lukecp · 03-16-2003, 01:06 PM

I would just go get a driveshaft out of a V8/3spd truck from the junkyard. BTW, i have seen V8's with HEI in the I6 position, the distributor does fit, but it is awful close to the firewall. If your broke a motor mount somehow, the HEI cap would proably get crushed when you revved the motor.

crazy longhorn · 03-16-2003, 04:51 PM

The sag 3spd+bell are the same lenght as a SHORT 350th. The HEI dist do clear, but are tight in I 6 position on the sb. the cap & rotor need to be off, to get the dist in /out of the eng. here are a few pics..... http://community.webshots.com/user/hotrodhorn you cant see the HEI, but its in there!

Johns70 · 03-16-2003, 06:05 PM

maybe thats what i did on the first pickup i had, when i did the swap. moved the engine to the forward mounts and used the long shaft trans so i wouldn't have to mess with the driveline leght.

MandarinSixSeven · 03-16-2003, 06:18 PM

mine is a 350 on the I-6 mounts...I didnt do the swap myself, the guy before did, but i wish that he would have done it right, because it is pretty tight at the dist. but not all that bad. The i dont like is that the fan is so far back its not really under the shroud

MandarinSixSeven · 03-16-2003, 06:20 PM

heres a pic

crazy longhorn · 03-16-2003, 06:23 PM

Methinks that would work John! The short 350t is a 6" tail, & the med lenght is 9".......there is actually another lenght(12"tail if I remember it right). At any rate, the longer trans would get you close enough for driveline lenght with the eng in v8 position & the I 6 shaft.......more than 1 way to "skin a cat"

crazyl

crazy longhorn · 03-16-2003, 06:26 PM

on the nose end, I use a 73 up waterpump, pulleys & acc to get the fan close enough to the rad without a 5" spacer

Longhorn Man · 03-16-2003, 06:29 PM

Or a 4X4 V-8 shroud would do the trick with the short pump.

03-16-2003, 10:13 AM	#1
dubie Registered User Join Date: May 2000 Location: Flin Flon, Manitoba, Canada Posts: 8,855	another engine swap question.....need som expertise I am pulling the inline 6 out of the 72 this morning along with the 3 speed tranny. My question is this...... If I was to get the V8 mounts, move them up to the proper spot and put my 350 there, will I have problems hooking up my driveshaft and shift linkages? I was speaking with a very wise mechanic last night and he figes that it's only about 3/4" that it will move up and there shouldn't be any problems with this. I always thought that you would need a longer driveshaft to do this. I could realy use your guys help on this because if i can put the 350 up farther so the HEI will clear the firewall some more, then I'm all for it. I just don't want to get into a whole bunch more work here. Many thanks __________________ My name's Tim and I'm a truckaholic My 56 Chevy shop truck build http://67-72chevytrucks.com/vboard/s...d.php?t=562795

03-16-2003, 10:28 AM	#2
crazy longhorn Fabricate till you "puke" Join Date: Jun 2002 Location: Ill Posts: 9,403	Your engine/ trans will move foward 3 1/2"(plus or minus 1/8") from I 6 to sb V8 position, so the front half of the d shaft will be that much too short. you will also need to replace the bell crossmember, or just run an auto crossmember under the stick trans(I6, & V8 bell crossmembers are different).Im not sure how that will affect the column linkage,as i ran a floor shifter in my stick trucks. good luck,crazyL Last edited by crazy longhorn; 03-16-2003 at 10:43 AM.

03-16-2003, 12:36 PM	#3
Johns70 Registered User Join Date: Dec 2001 Location: Spring Creek, nevada. U.S.A. Posts: 456	the saginaw 3-speed and bellhousing are the same leght as a th-350 long shaft tranny, hope this helps in your qeust __________________ 69 chevy short wide box project 70 GMC jimmy project

03-16-2003, 01:06 PM	#4
lukecp Formerly yellow72custom Join Date: May 2001 Location: Austin, TX Posts: 7,531	I would just go get a driveshaft out of a V8/3spd truck from the junkyard. BTW, i have seen V8's with HEI in the I6 position, the distributor does fit, but it is awful close to the firewall. If your broke a motor mount somehow, the HEI cap would proably get crushed when you revved the motor. __________________ '72 Chevy C10 Mild 350/TH350/3.07. Ochre/White. Old high school ride. '70 GMC C2500 '62 327 4bbl/SM465/4.56-geared Dana 60. White/White. Project or parts truck. '97 Saturn SL DD. 1.9/5-speed. 40+ highway mpg

03-16-2003, 06:05 PM	#6
Johns70 Registered User Join Date: Dec 2001 Location: Spring Creek, nevada. U.S.A. Posts: 456	maybe thats what i did on the first pickup i had, when i did the swap. moved the engine to the forward mounts and used the long shaft trans so i wouldn't have to mess with the driveline leght. __________________ 69 chevy short wide box project 70 GMC jimmy project

03-16-2003, 04:51 PM	#5
crazy longhorn Fabricate till you "puke" Join Date: Jun 2002 Location: Ill Posts: 9,403	The sag 3spd+bell are the same lenght as a SHORT 350th. The HEI dist do clear, but are tight in I 6 position on the sb. the cap & rotor need to be off, to get the dist in /out of the eng. here are a few pics..... http://community.webshots.com/user/hotrodhorn you cant see the HEI, but its in there!

03-16-2003, 06:18 PM	#7
MandarinSixSeven Seasonal Poster Join Date: Apr 2002 Location: Kelowna BC Canada Posts: 896	mine is a 350 on the I-6 mounts...I didnt do the swap myself, the guy before did, but i wish that he would have done it right, because it is pretty tight at the dist. but not all that bad. The i dont like is that the fan is so far back its not really under the shroud __________________ 67 GMC Short Step 350/4-Speed/3.08 Posi Front/Rear Sway Bars Kelowna BC, Canada Member of DTPW

03-16-2003, 06:20 PM	#8
MandarinSixSeven Seasonal Poster Join Date: Apr 2002 Location: Kelowna BC Canada Posts: 896	heres a pic Attached Images __________________ 67 GMC Short Step 350/4-Speed/3.08 Posi Front/Rear Sway Bars Kelowna BC, Canada Member of DTPW

03-16-2003, 06:23 PM	#9
crazy longhorn Fabricate till you "puke" Join Date: Jun 2002 Location: Ill Posts: 9,403	Methinks that would work John! The short 350t is a 6" tail, & the med lenght is 9".......there is actually another lenght(12"tail if I remember it right). At any rate, the longer trans would get you close enough for driveline lenght with the eng in v8 position & the I 6 shaft.......more than 1 way to "skin a cat" crazyl

03-16-2003, 06:26 PM	#10
crazy longhorn Fabricate till you "puke" Join Date: Jun 2002 Location: Ill Posts: 9,403	on the nose end, I use a 73 up waterpump, pulleys & acc to get the fan close enough to the rad without a 5" spacer

03-16-2003, 06:29 PM	#11
Longhorn Man its all about the +6 inches Join Date: Jan 2001 Location: Hilliard Ohio Posts: 2,693	Or a 4X4 V-8 shroud would do the trick with the short pump.



Register or Log In To remove these advertisements.

Register or Log In To remove these advertisements.