Motor mount differences

[models916]

Did we ever figure out if there is a difference in the SBC and the W engine rubber mounts? NAPA lists a different mount for 1962 283, 327 and 409. Is the 409 taller or positioned differently on the frame mount? Anybody know for sure? I was planning on removing the SBC poly mounts I have in place now with new locking rubber.

 

[PAINTJOHN1]

Models,small block mounts are lighter weight.My Anchor book from 1988 shows small block Chevy 1962-1967 as MT-2267.The book shows 409 Chevy 1961-1965 as MT-2285.These are a little wider and much heavier.I have a set of the MT-2285's and did not like the fit.What I did was have a friend of mine who works at a GM dealership look up the original GM number for 409.That number is not avialiable and is superseded with a cross over number that is to a 427ci big block number used in 1965-1969 big body Chevies.I then ordered the GM Mounts,with absolutely no regrets.They mounts were costly,but the fit is right on the money and its GM,Mark of Excellent quality,made in the USA,not some far eastern junk.That is the only mount I will use.If I find the GM number I will post it for you. John

 

[Ronnie Russell]

John, That would be great if you can post the GM number. Several aftermarket numbers will work, but I think all of us would spend more to get the correct high-quality part. Besides, I didn't know anything was still made in the U.S.A. Shoot,, I would even save the box.

 

[PAINTJOHN1]

This is the mounts that I used,GM part number 3990916.Both sides of car will take same number.GM charges around $100.00 for the pair,with the discount.Their application is for 427ci Chevy big body 1966-1969,made specifically for 1965 Chevy 409.(Impala,SS,Belair,Biscayne,and wagon).Try to Google the number,an application chart will pop up and show you the applications for 65,,409 Chevy and the 427ci applications.It is also used in Corvette applications. This is a cross over number,because the actual 409 mounts number has been discontinued..Like I said,I was totally dissatisfied with the mounts made in the last 10 years(terrible fit on the frame mount perches).All of the aftermarket mounts are made either in India,Korea,Turkey,China, or Vietnam.All brands of after market mounts are basically made by the same manufacturer.They are sold under 10-12 different companies,in name only.Ron,the last set I bought was about 2 years ago,the box was marked Made In USA.John

 

[models916]

This is my problem

The number 3990916 is .5 inches taller than the standard SBC mount I have on now. Show-Cars, Ecklers, Hubbards, etc. all use the SBC mount for all V8 58-64. The SBC is 1.5" from flat to center of bolt hole. Does anybody have an original mount for the 409? Was it .5" taller than the SBC mount? Hey Phil, what do you use when you put one together? thanks

 

[SSpev]

This may be of use

http://www.jegs.com/PDFs/555-MotorMounts.html

 

[PAINTJOHN1]

Models,I checked my after market mounts that I have in the garage.The aftermarket mounts for 65-69 Chevrolet are about 3/8" taller,however all holes for bolts including the long bolt that goes through the perches line up right on the money.They are much,much heavier and bigger.The 409 aftermarket mounts I have are about 1/8" taller than the small block mounts.They are a little heavier.The reason I did not use the 409 after market mounts was because they fit terrible on the perches.They were extremely sloppy.Thats when I went to GM and ordered the other ones.The GM mounts worked absolutely perfect on installation,fit the perches perfect.I have no vibrations or any issues since installing them 3 years ago.I've enclosed some pictures.!st picture is all 3 mounts together.Far left is the small block mount,center is the 409 mount,right is 409-427 mount.2nd picture is side view of mounts.The 409-427 is slighty taller,but holes for the 1 long bolt match exactly with the 409 and 327 mounts.3rd picture is comparing side view of the 409 and 409-427 mount.You can see how much heavier a mount this is.Last picture is comparing the 327 and 409 mounts.++NOTE++ All mounts shown are aftermarket mounts made in foriegn countries,not GM products. MODELS, Check out Tom's posting in the previuos blog,it gives all the dimensions. John

 

[models916]

thanks guys

Great chart, great pics. I see it is different. I guess I need to change mounts. thanks again guys.

 

[petepedlar]

I had a set of everyday small block mounts I was going to use when installing the 409 in the Impala. After reading this post I bought a set of the 427 mounts. They are a lot stronger, no doubt...... but there is no way they will fit onto the frame perches in my '61. I fought with them for about 2 hours but to no avail....... Of course I just bolted them to the engine and proceeded to try and install the 409 and 700R4 together........... I should have tried them on the frame first ...... they are two narrow for one thing, secondly the long tapered part will not allow it to sit down on the frame perches........ my car is a factory 348 car so maybe the perches are different. After enough frustration I put the small block mounts on and the engine fell into place........

Dave

 

[raymar58409]

I had the mounts off the 61 truck engine and they looked like they would have worked in my 58 Impala but during a garage cleanup they were accidentally thrown away along with my 76 454 suburban mounts. Right now the impala has a 350 SB so what do you think I will need for the 409 conversion. The last 58 I had had a 348 and put in a 409 so I probably used either the 348 or 409 mounts and didn't have to change perches. I suppose I will have to change perches???

Dave if you look at your suburban do you think those mounts might be able to work? I like that type of mount (captured )

Ray

 

[MileHiSS]

I bought these taller mounts from Summit to try and get some header clearance.

http://www.summitracing.com/parts/PTP-7-505-BL/?image=large

 

[1961BelAir427]

Models,
I was thinking of buying a set of the poly mounts, so I have to ask: Why are you changing from them? Did they give you trouble?