From 6 Cylinder To 8 Cylinder - Nova Tech
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  #1  
Old Jan 21st, 07, 09:47 PM
raddad2 raddad2 is offline
 
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Question From 6 Cylinder To 8 Cylinder

I built the 72 Nova from groud up but had problems with installing my 8 cylinder due to the motor mounts not matching the bolt holes. Does anybody know if the engine should fit without having to modify the chasis or if there are certain motor mounts that will fit? Any help will be appreciated because I am totally stumped.
Thanks in advance for any assistance given,
Rick
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  #2  
Old Jan 21st, 07, 10:43 PM
Big Dave Big Dave is online now
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Cool Re: From 6 Cylinder To 8 Cylinder

The old six cylinder frame pedestal stands are the wrong dimensions (size on the top of the stand were the motor mount bolts) and the pedestals are mounted to far back on the front cross member to mate up with a V-8 motor mount. You will need to buy V-8 SBC frame pedestals stands for the chassis and mount them to the forward three holes drilled in the cross member.


Big Dave
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  #3  
Old Jan 22nd, 07, 08:42 PM
70novadisease 70novadisease is offline
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Default Re: From 6 Cylinder To 8 Cylinder

Hello Rick,i have a 1970 nova,and i am currently in the process of the same deal as u,i had people tell me all kinds of stuff,the truth was nothing anyone told me worked,i tryied 6 sets of frame mounts,none of them worked,the bolt holes DONT lign up,i even bought 2 sets from year one,and they said they were the correct V8 mount,those also didn't work,so my advice to u is to order a set from year one,(clean the paint off,and check for cracks,mine were cracked by the bolt holes) and bolt them to the motor,set it into the car,measure off of a common hole/weld, or whatever,center the motor in the crossmember,(with the trans bolted on and the trans mount bolted to the crossmember) and weld'em on,thats what i had to do,i did the run around with people for weeks before just saying screw it and welding them,just do a nice job and hit the mount with some black paint and it'll look factory.....good luck-Dan
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Old Jan 22nd, 07, 09:14 PM
Big Dave Big Dave is online now
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Default Re: From 6 Cylinder To 8 Cylinder

Personally I would discourage the electric glue stick option. There are two different thickness motor mounts (no one but restoration shops sell the thin ones any more that go on with the 1967-'68 SBC) NAPA and most autoparts store only stock the '69 up motor mounts.

Then there is the issue of the frame mounts. That the motor mounts bolt to. There are three different applications.
1967-'68 283, 327,
1968-'69 307, 327, 350,
1969 302 for the SBC;

and two for the BBC 1967-'68 and then the '69 up was another.

That yields six different combinations for a SBC motor and eight different combinations for a BBC (since most try and use the SBC mounts).

I can supply you with the correct part numbers and pictures from an old Super Chevy article I have scanned (or you can go down to the local library and read the June 1991 article if they have it available). The correct parts are available to install any motor if you know what the dimensions should be. Once welded you will not only depreciate the value of your car but potentially weaken and compromise the structure (if anyone gets hurt in the potential failure only you will be liable; though I am not a lawyer and do not play one on TV).

At the time these parts were going together originally, GM was embroiled in the nations first recall of an automobile after a series of law suits in every state that spanned five years over failed motor mounts. So there were continual yearly design changes and upgrades that are not backwards compatible (GM designed them so they would not interchange with the bolt holes being off if mixed)

Big Dave
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Old Jan 22nd, 07, 11:24 PM
raddad2 raddad2 is offline
 
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Default Re: From 6 Cylinder To 8 Cylinder

I have not figured out the exact direction that I will take to resolve the mount issue but I appreciate the feed back from both of you guys. I have tried all of the available fixes and they simply do not work so I am bending to the direction that 70Novadisease has explored. Thanks again for the information.
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Old Jan 24th, 07, 06:07 PM
jim454 jim454 is offline
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Default Re: From 6 Cylinder To 8 Cylinder

If your going to weld them make sure you burn them in well. 7018 rev. polarity or mig weld them with er70s-6 .030 wire and uni-shield gas. Make sure you have good penetration,a lot depends on those welds ! Hope everthing goes well .
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