How much HP will stock motor mount bosses take with out distorting block

[2stangs69-91]

I am trying to decide weather to mount my Dart 408 IE blown stroker motor in my 1969 mustang using the stock mount location or use motor plates. The motor mount bolting area on the IE block is reinforced. I need to know how much HP will it take before trying to distort the block any. I can get mounts that will work. My motor set up should make well over 1000 hp. thanks for the info. mike

[PRO 1]

We have many customers who use these in engines producing more power than that, personally in all the years I have done this I cant recall a guy breaking off a mounting tab on an engine. I know the baja trucks even when flipping and flopping them all over the mounts never have any issues, we feel more than comfortable with them at your power level.

Thanks

JOhn

[2stangs69-91]

thank you for the reply. looks like I will go with the factory mounts. It will make it much easier. Mike

[MambaLeyla]

just as an FYI... I did mine last week for the second time, but now with the badass Energy Suspension mounts with the following tools:

1. floor jack
2. 5/8" combo wrench o==c
3. 11/16" combo wrench
4. 15mm combo wrench
5. T-handle torx wrench for skidplate bolts

I just took off the skidplates, put a rag on the cradle of the floor jack, jacked up the engine by its pan just enough to clear the mounts. This caused the whole front end to lift since the weight of the engine isnt on the suspension anymore, so I didnt need to take the wheels off. Then just turn turn turn the wrenches, curse curse curse the pinched fingers and battered knuckles, pausing for a beer after getting each side done and before cleaning up.

Four things of note on the Energy Suspension badass mounts, since this topic is stickied:

1. the heat shield wont fit exactly, but needs to be there. i managed to wiggle it in such a way that it cant fall out, but isnt bolted between the mount and the engine.

2. polyurethane transmits more vibration through from the engine to the frame than rubber. you will definitely feel more vibration at idle and under acceleration than the stock mounts unless yours were WAY shot - but that doesnt matter, because changing the stock mounts every 6 months is UNACCEPTABLE. Its not much vibration, but its there... if it actually bothers you, please dont procreate.

3. these mounts may position your engine slightly different than the rubber mounts did... you will have to check your fan shroud for clearance, and make sure theres a little extra clearance for when the engine moves under 4L torque yes, it will move a little even with these mounts. its normal

4. the Energy Suspension mounts are easier to put in than stock ones because you have more room around that pesky bottom bolt.

[Awesome Bill]

Stock style mounts were never, never, never, intended for drag racing. You can not even compare a baja truck application to drag racing or even stock car classes. It is not even close. What everyone here seems to misunderstand is a dead hook and transfer of torque!
You go ahead and run those stock mounts on just your engine mounts and you will have problems with main bearings! There is little to no strength in the side of the block, it is not solid and it moves all around under certain G forces.
The bell housing bulkhead is where the engine needs to be reinforced. Even in the baja truck racing they use mid plates, up to ½". You can not damage the bulk head on the rear of the block, you can even scallop a lot of it out and still not hurt it.
So, if your going to use the stock engine mounts, put a solid mid plate in between the tranny and engine and you will then have a stable engine that won't flex the block and mains under drag racing conditions. I recommend a mid plate with anything over 600hp and a drag race application.