GMC V6 to a V8 small block - The 1947 - Present Chevrolet & GMC Truck Message Board Network

Erl · 03-30-2002, 12:10 PM

I have a 68 GMC 305V6 3/4 4x4 that needs a 350V8. Is there a difference between the 2WD and 4WD small block frame motor mounts? Will the bell housing require changing?
Thanks in advance

lukecp · 03-30-2002, 12:50 PM

The bellhousing is exactly the same. Im not sure about the engine mounts though. What is so bad with the V6? Those things are bulletproof tourqe monsters!

------------------
Lucas

"Another proud owner of one of the coolest trucks ever built"

drop_shift@hotmail.com

My Daily-Driver: '72 Chevy LWB Custom/10. Rebuilt 350, 300 HP thanks to a few go-fast goodies. Ochre with a white top. Future plans include a frame off restoration, and maybe a blown 383.

Longhorn Man · 03-31-2002, 12:50 AM

From the stuff I see under my hood, i think the mounts and the perches need swapped out.
(my '69 GMC which had a 305 and now a 350)

------------------
'69 G.M.C. 350/350. Trying to clean up the left over damage from the Dope-Smokin-Old-Man
I've been dubbed the Longhorn Freak/Fanatic/Expert, I just hope I can live up to it.
Need to pick up the one ton Longhorn with a PONTIAC 350/350soon.
Thanks every one!

Check out The Longhorn Webite.
If you need a pic posted, E-mail me at longhornmail@yahoo.com
Andy, in Columbus Ohio

bigdog67gmc · 03-31-2002, 01:12 AM

just did the samething on my 67 gmc 4x4. u need to swap motor mount stands(cross member)motor mounts . bellhousing will work. might have to move the cross member to the back to holes in the frame where the v6 mounts are now.i found out the hard way that the 2wd v8 cross member would not work in my truck. some other members may have more info for u.

Longhorn Man · 03-31-2002, 01:14 AM

What cross member you refering to?

------------------
'69 G.M.C. 350/350. Trying to clean up the left over damage from the Dope-Smokin-Old-Man
I've been dubbed the Longhorn Freak/Fanatic/Expert, I just hope I can live up to it.
Need to pick up the one ton Longhorn with a PONTIAC 350/350soon.
Thanks every one!

Check out The Longhorn Webite.
If you need a pic posted, E-mail me at longhornmail@yahoo.com
Andy, in Columbus Ohio

bigdog67gmc · 03-31-2002, 01:24 AM

on the v6 the cross member runs at a angle from frame rail to frame rail. the motor mounts mount to it. not really like the v8 mounts that look more like a motor mount stand.hope this makes sense

Longhorn Man · 03-31-2002, 01:28 AM

Never looked at the mounts for a V-6...guess I need to go to the junk yard and investigate this.

------------------
'69 G.M.C. 350/350. Trying to clean up the left over damage from the Dope-Smokin-Old-Man
I've been dubbed the Longhorn Freak/Fanatic/Expert, I just hope I can live up to it.
FINALLY got the HORNIAC...a '70 one ton Longhorn with a Pontiac 350/350 and lots of 'personality'. Check out The Longhorn Webite.
If you need a pic posted, E-mail me at longhornmail@yahoo.com
Andy, in Columbus Ohio

bigdog67gmc · 03-31-2002, 01:33 AM

for some reason the v6 mounted in the frame rails wierd. i can say i hated the v6 with 456 gears 63 mph top speed with 35 inch tires.

[This message has been edited by bigdog67gmc (edited March 31, 2002).]

Erl · 03-31-2002, 10:11 AM

BigDog,
I really like my truck, but you are correct the V6 and low gearing make it almost unusable in town (Dallas). Did you put a 350 in your truck and did you change the diff gear ratios? Where did you get the motor mounting harware and how did you know it was correct? I am trying to get all the pieces before the motor swap begins.
Thanks

Rod · 03-31-2002, 10:38 AM

If some one can ...post a pic of the V6 4x4 mount...I have yet to see that set up. I did see a 4x4 that originally came with a V6 but didnt pay attention to the mount as it had a 350 in it already.... so I dont remeber if it was chnaged or not. Or email me the pic Thanks. Rod
chevytruckranch@hotmail.com

*Fast68Chevy* · 03-31-2002, 02:55 PM

i wanna see 4x4 V^ engine cradle too, should be interesting, then maybe we could figure this out, is probably just a differewnc ein the two engine cradle brackets/pads, im sire the actual cradle itself is probably same as the L6 and V8 one

------------------
Randy- Lincoln, IL
randy@ccaonline.com
-71/C-10(thx teeitup and crews!)350 4+4/CH465(thx 71Chev, GMCPaul, and CPNE)longfleet bed(thnx meathead95)!still building it-
-'84 Z28 H.O. 305 L69 700R4 GT4 3.73
- 1984 Firebird SE 2.8L T-5 GT4 3.73
-1981 Cutlass Supreme, dunno what im gonna do with it yet...
-79 G20 pass van, 350/th350/10bolt
*Paint is overrated
© RSS Enterprises 2000

fluffytx1 · 03-31-2002, 03:39 PM

heard motor mount changes need to be made But am keeping my 351 v-6 till she dies torque monster!!!

Erl · 04-01-2002, 09:21 AM

Fast68,
I have had several people try to sell me just the frame motor mounts, others say the cross frame cradle is also needed. I do not see any additional bolt holes to move the cross frame, but this does not mean that a V8 cross frame is the same. It could be shaped differently. The V6 has a complicated bracket on the engine to position the actual motor mount. This leads me to believe that the frame cross cradle is universal. Surely someone knows for certian.

03-30-2002, 12:10 PM	#1
Erl Registered User Join Date: Mar 2002 Location: Dallas, TX Posts: 555	GMC V6 to a V8 small block I have a 68 GMC 305V6 3/4 4x4 that needs a 350V8. Is there a difference between the 2WD and 4WD small block frame motor mounts? Will the bell housing require changing? Thanks in advance __________________ 1968 GMC 305 V6 3/4 4x4 Stepside 06 Corvette Daily Driver Dallas TX

03-30-2002, 12:50 PM	#2
lukecp Formerly yellow72custom Join Date: May 2001 Location: Austin, TX Posts: 7,531	The bellhousing is exactly the same. Im not sure about the engine mounts though. What is so bad with the V6? Those things are bulletproof tourqe monsters! ------------------ Lucas "Another proud owner of one of the coolest trucks ever built" drop_shift@hotmail.com My Daily-Driver: '72 Chevy LWB Custom/10. Rebuilt 350, 300 HP thanks to a few go-fast goodies. Ochre with a white top. Future plans include a frame off restoration, and maybe a blown 383. __________________ '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

03-31-2002, 01:12 AM	#4
bigdog67gmc Registered User Join Date: Sep 2000 Location: Fresno CA Posts: 41	just did the samething on my 67 gmc 4x4. u need to swap motor mount stands(cross member)motor mounts . bellhousing will work. might have to move the cross member to the back to holes in the frame where the v6 mounts are now.i found out the hard way that the 2wd v8 cross member would not work in my truck. some other members may have more info for u. __________________ Big Dog 67 GMC, 4x4, 4" lift, 35 groundhawgs, under construction, Fresno, CA

03-31-2002, 01:24 AM	#6
bigdog67gmc Registered User Join Date: Sep 2000 Location: Fresno CA Posts: 41	on the v6 the cross member runs at a angle from frame rail to frame rail. the motor mounts mount to it. not really like the v8 mounts that look more like a motor mount stand.hope this makes sense __________________ Big Dog 67 GMC, 4x4, 4" lift, 35 groundhawgs, under construction, Fresno, CA

03-31-2002, 01:33 AM	#8
bigdog67gmc Registered User Join Date: Sep 2000 Location: Fresno CA Posts: 41	for some reason the v6 mounted in the frame rails wierd. i can say i hated the v6 with 456 gears 63 mph top speed with 35 inch tires. [This message has been edited by bigdog67gmc (edited March 31, 2002).] __________________ Big Dog 67 GMC, 4x4, 4" lift, 35 groundhawgs, under construction, Fresno, CA

03-31-2002, 12:50 AM	#3
Longhorn Man its all about the +6 inches Join Date: Jan 2001 Location: Hilliard Ohio Posts: 2,690	From the stuff I see under my hood, i think the mounts and the perches need swapped out. (my '69 GMC which had a 305 and now a 350) ------------------ '69 G.M.C. 350/350. Trying to clean up the left over damage from the Dope-Smokin-Old-Man I've been dubbed the Longhorn Freak/Fanatic/Expert, I just hope I can live up to it. Need to pick up the one ton Longhorn with a PONTIAC 350/350soon. Thanks every one! Check out The Longhorn Webite. If you need a pic posted, E-mail me at longhornmail@yahoo.com Andy, in Columbus Ohio

03-31-2002, 01:14 AM	#5
Longhorn Man its all about the +6 inches Join Date: Jan 2001 Location: Hilliard Ohio Posts: 2,690	What cross member you refering to? ------------------ '69 G.M.C. 350/350. Trying to clean up the left over damage from the Dope-Smokin-Old-Man I've been dubbed the Longhorn Freak/Fanatic/Expert, I just hope I can live up to it. Need to pick up the one ton Longhorn with a PONTIAC 350/350soon. Thanks every one! Check out The Longhorn Webite. If you need a pic posted, E-mail me at longhornmail@yahoo.com Andy, in Columbus Ohio

03-31-2002, 01:28 AM	#7
Longhorn Man its all about the +6 inches Join Date: Jan 2001 Location: Hilliard Ohio Posts: 2,690	Never looked at the mounts for a V-6...guess I need to go to the junk yard and investigate this. ------------------ '69 G.M.C. 350/350. Trying to clean up the left over damage from the Dope-Smokin-Old-Man I've been dubbed the Longhorn Freak/Fanatic/Expert, I just hope I can live up to it. FINALLY got the HORNIAC...a '70 one ton Longhorn with a Pontiac 350/350 and lots of 'personality'. Check out The Longhorn Webite. If you need a pic posted, E-mail me at longhornmail@yahoo.com Andy, in Columbus Ohio

03-31-2002, 10:11 AM	#9
Erl Registered User Join Date: Mar 2002 Location: Dallas, TX Posts: 555	BigDog, I really like my truck, but you are correct the V6 and low gearing make it almost unusable in town (Dallas). Did you put a 350 in your truck and did you change the diff gear ratios? Where did you get the motor mounting harware and how did you know it was correct? I am trying to get all the pieces before the motor swap begins. Thanks __________________ 1968 GMC 305 V6 3/4 4x4 Stepside 06 Corvette Daily Driver Dallas TX

03-31-2002, 10:38 AM	#10
Rod Join Date: Dec 1999 Location: Eastern - Manitoba Canada, Winnipeg Posts: 4,369	If some one can ...post a pic of the V6 4x4 mount...I have yet to see that set up. I did see a 4x4 that originally came with a V6 but didnt pay attention to the mount as it had a 350 in it already.... so I dont remeber if it was chnaged or not. Or email me the pic Thanks. Rod chevytruckranch@hotmail.com __________________ Senior active founding member. 70 3/4 ton GMC Suburban 4x4 250/4 spd. 71 1/2 ton Suburban Chevy 4x4, 350/350 72 Chev 1 ton tow truck 402BB w/Holmes 440 wrecker on propane 2005 FLSTSCI Harley Springer 85 FXSB Harley Lowrider 72 Triumph 650 Bonneville 5spd "Poor people don't have hobbies" Quote from wife.

03-31-2002, 02:55 PM	#11
Fast68Chevy Account Suspended Join Date: May 2000 Location: IL Posts: 0	i wanna see 4x4 V^ engine cradle too, should be interesting, then maybe we could figure this out, is probably just a differewnc ein the two engine cradle brackets/pads, im sire the actual cradle itself is probably same as the L6 and V8 one ------------------ Randy- Lincoln, IL randy@ccaonline.com -71/C-10(thx teeitup and crews!)350 4+4/CH465(thx 71Chev, GMCPaul, and CPNE)longfleet bed(thnx meathead95)!still building it- -'84 Z28 H.O. 305 L69 700R4 GT4 3.73 - 1984 Firebird SE 2.8L T-5 GT4 3.73 -1981 Cutlass Supreme, dunno what im gonna do with it yet... -79 G20 pass van, 350/th350/10bolt *Paint is overrated © RSS Enterprises 2000

03-31-2002, 03:39 PM	#12
fluffytx1 Registered User Join Date: Feb 2002 Location: point blank Posts: 113	heard motor mount changes need to be made But am keeping my 351 v-6 till she dies torque monster!!! __________________ 1968 GMC CST long wide box http://groups.yahoo.com/group/67-72-collectors/

04-01-2002, 09:21 AM	#13
Erl Registered User Join Date: Mar 2002 Location: Dallas, TX Posts: 555	Fast68, I have had several people try to sell me just the frame motor mounts, others say the cross frame cradle is also needed. I do not see any additional bolt holes to move the cross frame, but this does not mean that a V8 cross frame is the same. It could be shaped differently. The V6 has a complicated bracket on the engine to position the actual motor mount. This leads me to believe that the frame cross cradle is universal. Surely someone knows for certian. __________________ 1968 GMC 305 V6 3/4 4x4 Stepside 06 Corvette Daily Driver Dallas TX



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