I think people have different opinions on the mounts because it differs from motor to motor. Better balanced motors I think don't transmit as much vibration. I had them on a 70 C10 with a cheap 350, alot of vibration even with a mild cam. I also had them on my Cutlass with a hot street 400 with a barely streetable cam that idled above 1000 rpm and they weren't that bad but that motor was well balanced. What I did on the C10 that was a good balance was I added nylon washers sandwiched with a regular steel washer to the motor mount bolts that bolt to the block. Nylon washers are nearly indestructable and took the edge off the vibration.

 

[QUOTE=OzzyTom;1571498191]Or you could use standard rubber mounts and put a bolt through it. Works well for me.

Rubber is still there to absorb vibration, bolts are there to prevent breakage from over extension!

I think that mount has a crack in it above and to the left of the bottom screw

 

thought my eyes were seeing double for a moment...
i think thats just rubber glue slag.

 

No very small hairline crack from left to right above the lower bolt, jeese I don't even have my glasses on

 

only tom can say for sure. he had it in front of him once but i still think its slag.a few times i have bough mounts they have had dribbles like that across them.

 

I've got solids in my 65 and 71. Just put moroso 62530 in my 65 and the is no change in vibration or noise. I can see no reason at this point to ever go back. JMHO. Ron B.

 

Maybe it's time for you to get glasses then....

Definitely NOT a crack.
Checked some other photos I have of the mounts....
That's just a surface scratch on the painted surface.
But thanks for the heads up.

Now this is a cracked mount....



It let go the first time I did a full throttle clutch dumped takeoff with the new motor.

The bolt mod has stood up well ....No issues with hard takeoffs now.
Except for keeping it going in a straight line

 

I have not tried them, but did hear the reason no vibes is because the body of the car sits on rubber body mounts ,which cancels most of the vibration.
Another thing solid motor mounts tie the front frame together thru the block,acts like a frame stiffner. but puts more stress on the block which could lead to a cracked block( maybe).

 

I received the Moroso solid motor mounts the other day from Summit as well as a pinion angle gauge from Comp Engineering.
Going to swap the motor mounts out and check the tranny, driveshaft and pinion angles one of the upcoming days.

Just got done stuffing a 383 sbc and beefed 700R4 (capable of supporting 700hp) into my brothers 3rd gen firebird so I should have some time this sunday or the first two weeks of October since I'm on vacation.

 

Finally got around to installing the Moroso BBC solid motor mounts last Saturday and am just finding time now to post the pics.

Install wasn't terrible. Had the car up on jack stands (all 4 corners) to access the motor mounts from below. The hooker sidepipe headers were a PIA b/c it prevented the poly one's from sliding out the top but I was able to "pursuade" them out and the solids on.
There is no play in the solid mounts when installing so getting them to fit with all the bolts was a process in it self on the driver side.
Passenger side went much easier.

Results: A bit more vibration but not alot. I think the fact that I have the jeep box and universal joint is where I feel the vibration in the steering wheel. When I say vibration...I feel the engine running, much like if you stuck you hand on the hood. I think the solid connection between the jeep box which is mounted directly to the frame then thru the solid universal joint from borgeson to the steering wheel is where the vibration is noticable. The body mounts prevent more vibration from being felt (and I have poly body mounts).

Driver side


Pass side


I feel like the engine is more connected to the frame via the solid mounts, despite the poor pictures below of the energy suspension poly mounts the driver side poly mount is very melted from the headers and the poly is very much flexible, more than rubber. So the engine had a lot of play even at idle with the poly mounts in their current condition.
I even had the aluminum shields that came stock from the factory.

The one on the right is the driver side.
I actually had to cut away some poly with an exacto knife that had melted over the bolts that held it to the engine block just so I could access the bolts to get them off.



My only concern now is the stress this is putting on the Merlin 509 block. When tightening down the solid engine mounts it definitely pulled the frame in towards the block but I am hoping that is because the car was up on jack stands and the frame was tweaked.

 

I replaced my broken rubber mounts (an anual event for years...) with solids a few weeks ago. Didn't notice any additional vibration or other unusual effects until I punched it and broke a dam spindle. Sheared it off at the spline.

 

This comment made my day! your agony took my from concerned that my poly mounts might be a problem to lmao in a few lines.

 

Damn I just ordered some Polymounts for my BB install....maybe I should look into the solids. I also have the hooker Supercomp header, not the side pipe versions so mine might even be worse for the mounts. That sux.

 

BTW, a few years ago we had a decent BB in my dad's 59, it was mounted using a motor plate, we didn't have any vibration problems but the freshly restored body did develope some stress cracks pretty early on, even with low/easy miles. We pulled the BB out and went back to a ZZ4 and stock rubber mounts and had no more cracks develope for several years afterwards. That BB with an old school 292H cam definetly shook that car around at idle but it was nothing killer...A damn solid roller 496 would have probably shook the fenders off of it...lol

 

The spindle was likely flawed or just weak due to 40 years of fatigue. The guys at work sure were impressed. The funny thing is the car has 6 "made in China" greasable u-joints. Less than $10 each and I'm replacing a spindle? How can it be?

I did notice the car was pulling strong and felt great for those 4 or 5 miles untill... and of course I left home without my cell phone...

Anyway I'll keep the solid mounts!

 

Is it auto or stick ?

 

TKO-500 5-Speed

 

Like I said in a previous post, I didn't like the bang I was getting shifting gears. There is no give or play like rubber or poly so the motor doesn't move and this transmits the impact of the gear change down the drive train putting more strain on the parts.

Mine would bang on an easy gear change with previous 550HP 406ci so I went with poly mounts when I installed the 427ci small block and no more bang between gears

 

Ditto - with old 427. When I installed new 489 I replaced mounts with stock units - drivers side lasted 10 minutes - passenger side lasted 2 weeks. Used Energy Prothane to replace - these work really well, I have improved shifter response and the shrould doesn't get eaten my the fan anymore

 

I run solid mounts after replacing rubber ones over the years. I run road race track days and the solids allow me to run the exhaust higher because the engine doesn't move so now I get more clearance on a lowered car.

Two positives I found: Chassis seems stiffer as the engine becomes a stress member. I don't have exhaust leaks as engine/exhaust doesn't move within chassis.