Front motor plate question

[68 chevelle]

At what point does a person use a front motor plate in a car with the stock frame? I ask because my engine builder thinks i need one. He says that with the power my motor makes it puts too much stress on the side of the block where the motor mount is. I keep telling him solid motor mounts are fine but it does make me think.

[supernova]

My car should run about what your's does when finished. I have a mid plate and motor plate.

[chpcamaro]

well solid motor mounts are fine but it puts a lot of stress on the cyclinders and can also cause you to take a chunk out of your block after time with anough hp. i would do motor plates if you can. i have had 2 guys bring there cars in with chunks missing and broken tail shafts funny thing is both motors still ran but the blocks were junk go figure.
just my 2 cents
rob

[ProCar]

It gives you a chance to align the engine with the pinion better too. Especially if a Ford rear was swapped for a 12 bolt, ride height change, etc. It requires a trans crossmember, but it's worth it.

Use a limiter, the engine just floats in those thin plates.

[John_Heard]

Here's a video of a good example of what happens with solid motor mounts with a high hp engine. This is if I remember right a 540 with two foggers on it, motor mount bolts break, binds up the throttle linkage locks motor wide open on the spray. Nuff Said.. Do the motor plates front and mid.

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[wikd69]

well solid motor mounts are fine but it puts a lot of stress on the cyclinders and can also cause you to take a chunk out of your block after time with anough hp. i would do motor plates if you can. i have had 2 guys bring there cars in with chunks missing and broken tail shafts funny thing is both motors still ran but the blocks were junk go figure.
just my 2 cents
rob

You've seen it rip the side of the block apart using solid motor mounts ? Dang, how much horsepower does it take to do that ?

I'm using solid mounts on my 427, but I'm probably making less than 700 hp or so - big numbers but not *monster* numbers. I'm stepping up to more boost and should gain a good bump in grunt, but still not in the range where running conventional solid mounts would be an issue for me, do ya think ?

[Hitchcock]

At what point in power does it require plates over mounts. Or is this a loaded question. I don't think I have ever seen 1000 hp car without plates.

[chpcamaro]

remember after time the block gets stressed and things go arye also it depends on how much your racing it a street car probably won't have a problem but a car that is run at a track should cheap insurance solid motor mounts and a front plate will be fineand front plate's are very easy to installyou saw johns video. oh you know what i might have pictures of one of the block at work if i do i will post it. the motor was in a 71chevelle it was a 10.50 car all motor i think it was a bbc 402 if i remember right.
rob

[wikd69]

remember after time the block gets stressed and things go arye also it depends on how much your racing it a street car probably won't have a problem but a car that is run at a track should cheap insurance solid motor mounts and a front plate will be fineand front plate's are very easy to installyou saw johns video. oh you know what i might have pictures of one of the block at work if i do i will post it. the motor was in a 71chevelle it was a 10.50 car all motor i think it was a bbc 402 if i remember right.
rob

Now I'm gonna have bad dreams.

[Craig W.]

What about a front plate with a stock rear tranny crossmember? (no mid plate?) Is that a no-no?

[John_Heard]

I don't know about not using a Mid Plate Craig. I've seen people use a mid plate and stock mounts up front and they've still bent the solid motor mounts (low 5 second car). I'd recommend using both front and mid plates. The mid plate is really nice when it comes time to pull a trans.

On another note, with motor plates you're supposed to use lateral limiters too. I've seen fast cars get by without them but some cars will bend the motor plates without them. Here's what the laterals look like on my car, they are tied to the motor mount locations and run forward to the subframe using aluminum radius rods.

[vegaracer]

We used to run a motor plate and a tranny mount only in our old mustang, and never had a problem, but it was only making mybe 400 -500 hp.

[Craig W.]

Thanks for the info John. I was hoping to avoid the mid-plate, as it seems like it would be a big pain in the butt. Maybe its not.

All this extra equipment is going to kill my front end weight reductions!

[supernova]

Thanks for the info John. I was hoping to avoid the mid-plate, as it seems like it would be a big pain in the butt. Maybe its not.

All this extra equipment is going to kill my front end weight reductions!

I know what you mean on the weight reduction thing. What am I doing.



Thanks John for the pic of the limiter. I wasn't sure how I was going to put mine in.

[John_Heard]

I just thought about something else to mention on the motor plate thing. When you're making your frame mounts put a horizontal tab that the motor plates can rest on when the bolts are out. That makes it a lot easier to line everything up as you just sit the engine down on those tabs and start the bolts. You can just barely see the tab on mine in the picture above.