View Full Version : 69 Pontiac Firebird 400 Engine Mounts?
AM.MSCL
02-25-2011, 06:01 AM
As with all other Pontiac things being totally different from Chevy parts I can not interchange the Engine mounts are even more rare.
Parts stores can not get then because they have no listing or the listing they reference is a chevy part.
Energy Suspension does not have a listing nor do any other eurathane companys.
I really do not want to do solid on both sides of the motor but would consider one side but solid mounts are hard to find in stock.
The only other thing that I have heard of is "Mighty Mounts" and Performance Years have mixed reviews. If you have feedback please I welcome it!:thumbsup:
Does anyone here at :lateral: have any other recommendations?
thanks
Ray
wmhjr
02-25-2011, 08:15 AM
I can help you out easily. First of all, engine mounts are readily available through companies like Butler Performance. They carry both solid, and MityMounts. I've bought both from them. You won't likely find anything from Energy Suspension or other normal aftermarket companies.
I've used MityMounts, but removed them from the car. I had an incident where the MityMounts failed under far too small of a situation. I have pics of the destroyed MityMounts. I switched to solid mounts on both sides, and am totally happy that I did. I'm running a stroked 462 making 600hp through a .660 lift roller cam at 11:1 compression. You would never be able to guess the mounts are solid unless you looked very closely.
http://www.jbp-pontiac.com/products/fasteners/motorMounts.htm
67 455 Bird ragtop
02-25-2011, 10:27 AM
WOW ... I've not heard of a mitymount failing before. What did they tell you ???
wmhjr
02-25-2011, 03:26 PM
The failure was not a normal operational failure. However it did fail and I didn't like the result. I didn't even talk to the manufacturer as I didn't consider it a normal use issue, and didn't feel they should be responsible. If I were just running 300hp, I may well have stuck with them. At 600hp, I was not inclined to take any more chances. I have heard of the mounts failing before, but those also were relatively high hp applications, and really my understanding of them is that they're really designed for under 500hp or so.
dhutton
02-25-2011, 03:40 PM
Ames Performance sells OEM style, Mitymounts and solid mounts.
mklinger
02-25-2011, 03:45 PM
Napa has them
T_Raven
02-25-2011, 09:11 PM
I've got OE style mounts I bought from one of the restoration parts places, but I'm not making much power yet so who knows what they can handle. I never even thought about the lack of poly mounts available.
wmhjr, how much vibration do you feel when driving it with the solid mounts?
wmhjr
02-25-2011, 10:24 PM
I've got OE style mounts I bought from one of the restoration parts places, but I'm not making much power yet so who knows what they can handle. I never even thought about the lack of poly mounts available.
wmhjr, how much vibration do you feel when driving it with the solid mounts?
Just to be as specific as possible, IMHO I probably have the worst case combination. I'm running an 11:1 compression .660 lift solid roller cam, bored 400 block and forged stroker crank in a pontiac standard block. I'm running a Lee 670 box with a Borgeson stainless U-joint - no rag joint. 600hp/tq roughly. How much do I feel it?
I don't. I guess there's a little bit of vibration at idle, but very little. I don't even notice it. While driving, there's nothing. I feel far more road feedback (asphalt surface, etc). There is absolutely no way I would change back from solid mounts. The rotating assembly was balanced well during the build, and it's a great motor, but I can only imagine that if you were not running a stroker with a lumpy cam, you couldn't even notice it no matter what.
T_Raven
02-26-2011, 09:59 AM
Thanks man, I'll have to try some solid mounts then when I finally build the stroker I want.
wmhjr
02-26-2011, 03:41 PM
I'm preparing for and trying to get to some events like mmmc, msc this year. If you're going to be at one you're more than welcome to see for yourself.
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