| Author |
Message |
Chris Christensen (Chris4905)
Registered Member
Username: Chris4905
Post Number: 8
Registered: 11-2004
Posted From: 67.60.70.125
Rating: N/A
Votes: 0 (Vote!) | | Posted on Sunday, February 04, 2007 - 10:23 pm: | |
I have a 1974 GMC 4905 that came with an 8V71 & Spicer 4 speed. The 8V71 is blown and will come out. I figure now is a good time to do the transmission conversion, so the 4 speed will also come out.
I have obtained a takeout 6V92TA & V730 from Nimco, they were matched and in a Grumman/Flexible 870. I understand this is also a 42 degree tilt and is the closest match to the 4905 for the swap. The 6V92 came still on it's cradle own cradle, although it was torch cut out of the Flexible. The 6V92 cradle still be used if necessary.
One of my biggest constant concerns is the match-up of the 6V92 to the 8V71 cradle. I'm thinking of using the 8V71 cradle after taking the 8V71 off of it, due to it matching to the current location of the front engine mounts on the bulkhead and also matching the rear engine hangers.
I have looked at both the 8V71 rear engine mounst, and the 6V92 rear mounts, and they look to be the same, measurements also appear to be real close. Can I be lucky enough to have these the same, and a match? I have also looked at the front mounting plates on both engines and it's really hard to determine if they are interchangeable. Will the 6V92 front mounting plate match to the front of the 8V71 engine cradle?
Has anyone already done this conversion, and if so, what is the best way to go, should I put the 6V92 on the 8V71 cradle, or leave the 6V92 on it's own cradle, install the 6V92 on it's own cradle into the bus, and finding some 6V92 engine brackets and welding them to the buldhead?
Thanks,
Chris Christensen |
Bill Gerrie (Bill_gerrie)
Registered Member
Username: Bill_gerrie
Post Number: 69
Registered: 3-2006
Posted From: 209.50.74.32
Rating: N/A
Votes: 0 (Vote!) | | Posted on Sunday, February 04, 2007 - 11:08 pm: | |
Chris
This is the exact change I did one year ago. I used the 8V cradle and cut and rewelded the front mount. Double check your measurements before you reweld. I wish I had. I had to remake the front mount. The rear mounts are identical. Does the 6V92 have the spacer ring between the engine and tranny? I didn't think the Grummn had them. If not you will have to install one to clear the rear mount with the V730. Nimco has these. If it is off a VS2 tranny you will have to weld up the hump on the ring to match the 6V and tranny. Try and get one from an 6 or 8V to save you the trouble. Hope you got the rad as well. If not there is a guy in NY that got me one to fit the 8V rad tanks so I didn't have to rework that part. Feel free to email me if I can be of any help. Bill |
Mark Karlsson (Flying_fishbowl)
Registered Member
Username: Flying_fishbowl
Post Number: 8
Registered: 2-2006
Posted From: 67.188.211.79
Rating: N/A
Votes: 0 (Vote!) | | Posted on Monday, February 05, 2007 - 12:45 am: | |
Chris: I recently completed putting a 6V92 and a 730 out of a Grumman into my GMC 4516 fishbowl. Here's a link to my post here at busnuts about it:
http://www.busnut.com/bbs/messages/233/14369.html
As Bill said, you'll need the spacer ring from a VS2 in order to move the transmission far enough to the passenger side of the bus. You'll also need a longer spline shaft to mate the transmission to the engine. I bought one through Mohawk Mfg & Supply Co. Their part number for the shaft you will need is 29510672. Their phone number is (847) 647-9350. I had to make spacers at either end of the shaft to centralize it in the engine and transmission splines.
I had to do modifications to my cooling system reservoir tank outlets and both upper and lower radiator pipes. If you want, give me a call @ (707) 258-2804 and we can talk about the modifications I did. Best time to catch me is in the evening, 7-10 p.m., Pacific Time.
Mark Karlsson |
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