[Rich D]

Looking for suggestions on the strongest motor mount other then solid. Motor is 455 and in a 70 LeMans.

[steve25]

You want them to have the folded over lock tab.

At times I have had better luck with the standard rubber ones then the Poly lined ones, and at other times not , so I don't fur sure know what to tell you .

One thing for sure is if your car has a Posi rear I can tell you that you should still add a limiting safety chain or the Rods with the eye bolt ends.

[1968GTO421]

Originally Posted by steve25

You want them to have the folded over lock tab.

At times I have had better luck with the standard rubber ones then the Poly lined ones, and at other times not , so I don't fur sure know what to tell you .

One thing for sure is if your car has a Posi rear I can tell you that you should still add a limiting safety chain or the Rods with the eye bolt ends.

Excellent advice from Steve. I have heard though of guys running a solid mount on the left side and a regular rubber type mount on the right side. I've been told there is little to no increase in noise/vibration. FWIW

[locomotivebreath]

Check out Butler Performance . They have a few options . I bought their stainless/poly mounts .

[gtobob67]

After losing 2 rubber mounts, I went this route. No more worries. This is in a 455 4 spd.

[1968GTO421]

^^ That looks foolproof! Nice work.

[Tom Vaught]

Originally Posted by gtobob67

After losing 2 rubber mounts, I went this route. No more worries. This is in a 455 4 spd.

That is the cleanest installation I have seen for a Power Steering built engine as far as engine retention goes, Nice Design & Fabrication Work there.

Tom V.

[FrankieT/A]

Clamshell...

[nhracecraft]

Originally Posted by gtobob67

After losing 2 rubber mounts, I went this route. No more worries. This is in a 455 4 spd.

That looks Awesome (and Extremely effective)....Details please ;-)

[Brian Baker]

Butler sold these type of mounts at one time. They may still do.

Originally Posted by steve25

You want them to have the folded over lock tab.

At times I have had better luck with the standard rubber ones then the Poly lined ones, and at other times not , so I don't fur sure know what to tell you .

One thing for sure is if your car has a Posi rear I can tell you that you should still add a limiting safety chain or the Rods with the eye bolt ends.

[439gto]

I got tired of breaking mounts, so on the drivers side I drilled a hole in the center of the mount, countersunk the frame side, and put a lock nut on the block side with a little red Loctite and just snugged the bolt up. No more broken mounts!! I used 5/16 because that's what I had on hand, but if I do another one I'll use 3/8.

[lust4speed]

Chain is good because the engine mount retains the normal free movement. Chevy at one time had a kit with a cable instead of a chain, and that seems better because of lighter weight and no rattling chain links. Would be more work but probably worth it.

I had chain and really didn't ever feel it while my son's Firebird had a turnbuckle making the assembly solid. The firebird shook pretty good at idle which looked cool, but don't know if I would want that on a daily basis.

[gtobob67]

Originally Posted by nhracecraft

That looks Awesome (and Extremely effective)....Details please ;-)

Here's a picture I saw from "Mancini Racing". My set-up is a copy of this. I made a bracket that mounts to the frame and one that mirrors the P/S mount to attach the turnbuckle. My brother in-law is a machinist so I had him mill the back of the aluminum P/S mounting bracket the thickness of the new turnbuckle mount so it doesn't affect the belt alignment. It's adjustable with the rubber or poly shock mount tension used. I used poly. I feel no vibration difference at idle. It has the stump puller roller cam.

[Sirrotica]

I've used turn buckles since I raced the 69 GP in my signature picture, since the late 70s, probably about 1978 after I couldn't keep any motor mounts intact for more than 2-3 weeks. Since a oval track car is braked hard approaching the corner the left one isn't the only one that gets abused. I used them on both sides of the engine. I had them in place for 3 years and never broke any mounts in 3 years of competition after installing the turn buckles.

I've never used rod ends on the turn buckles, I just use the type with a looped end on it and adjust it so there is about 1/8th of an inch of play before it comes into contact with the bolt on the engine. That way there is no need for a rubber mount on one end, and the OEM mounts can do their job as intended.

I've dreamed up a combination of a cable, and a turn buckle that would attach on the water crossover with a bracket as the anchor point to remove torsion stress from the oil pan rail area, hopefully aiding against bulkhead cracking in the #2-3 main bearings. The water crossover would spread the stress to both banks, rather than the left bank taking all torsional stress in the oil pan rail area where the factory mounts attach. Motor plate mounting accomplishes this but for people that have street cars, most aren't going to go to the trouble of installing a motor plate system.

After seeing some of the photos of blocks splitting on the center bulkheads, I cringe when some people post that they use a solid mount on the drivers side after seeing the blocks eventually fail in the bulkhead area. Hence the reason to restrain the engine near the water crossover area.

I just need to get my rear in gear and fabricate the vision I have in my head. I believe the Pontiac people would support such an innovation to help with block longevity, and still be able to use the OEM style motor mounts the way they were intended...........

[form74]

I demolish stock motor mounts both of them were wasted.

Then I bought the mity motor mounts, And destroyed the driver side.

Then I went and bought solid mounts for my car just put the drivers side on and left the mity mount on the passenger side.

Been that way over 8 years , two motors and at least 500 passes

Saw this on a TA a few years ago

[firechicken]

On my F body, I have a 1" x 3/8" steel flat stock bar that is bolted to the bell housing with a longer grade 8 bolt in a stock bolt hole and attached to the lower A arm mount with a heavy washer welded to the end of the flat bar and an additional nut on the exposed threads that are still available there.

Invisible from under hood and, I feel, a better anchor point than the cylinder head.

[Sirrotica]

After studying the evolution of PMDs motor mount program since they designed the 455, and changed the whole system just for the added torque of that engine.

I believe if you have the 2 hole mounts ( pre 70 chassis and blocks) that only straddles the #3 main bulkhead you're subjecting only 1 bulkhead to all the torsional stress. The redesign of the mounts in 1970 spreads the load over both the #2 and 3 bulkheads. Pontiac engineers were aware that the 2 bolt mount system was putting all the stress on only one small area. The redesigned system spreads the load over a larger area and there were stiffening ribs added to the 3 bolt system to further spread the load on the left side of the block. Even though the A bodies still used the 2 bolt system on the 400 engines until 1972, the 455 cars from 1970-72 had a completely redesigned system for the new 455 engine that used the newer 3 bolt mount system. Obviously Pontiac had a concern that the older system was going to cause some unwanted problems with the higher torque 455s

The three bolt mount system is a much better engineered system than the previous 2 bolt system engineered when the engine was only available in 287 cubic inches. As the cubic inches increased as well as the torque output the older 2 bolt system needed to be updated. You can see the added strength, and engineering improvements just by observing an early bare block compared the a late model block side by side.

Anyone getting away with the solid left mount is going to be tempting fate of splitting the block much less if they're using the 3 bolt mount system, rather than the 2 bolt older system. That reason may be why some people seem to get away with a solid mount on the left side, and some don't. The two systems are not equal in strength by any means.

My 1969 GP dirt track car had a 428, and used the older 2 bolt system, in 1970 the GP completely changed the motor mount system over to the superior 3 bolt mount system on all engines. On A bodies only the 455 cars received the newer/stronger mount system. Since the 69 GPs had yet to receive a motor mount update I started using the turnbuckles to supplement the older weaker 2 mount system.

[1968GTO421]

Originally Posted by 1968GTO421

Excellent advice from Steve. I have heard though of guys running a solid mount on the left side and a regular rubber type mount on the right side. I've been told there is little to no increase in noise/vibration. FWIW

Disregard, more info indicates this is not a good idea. See post 14 on this thread or link here.

http://forums.maxperformanceinc.com/...0&postcount=14