caldercay

Here's a quote from Dave at Yank Performance (torque converters):

"... the poly mount will break the tail housing overtime and is not
needed unless the frame is tied together with a roll cage.

Best Regards
Dave Myers
Yank Performance Mfg."

... and here is a response from Chuck at FLT:

"I think using the entire kit you'll be ok, most guys just use the trans
mount which I think causes problems at times because the motor is
moving more than the trans. I don't hear about the LT1 tails cracking
like the LS1 tails for some reason, maybe because the difference in
size. The only thing I don't like about them in a daily driver is that
they can cause excessive vibration that you might not like."

Personally, to be on the safe side, I am going to leave the stock rubber
tranny mount and maybe sell the Prothane poly tranny mount that is
still in the sealed carton.

Pro_built7

ya ^^ you'll be fine with the whole kit. just don't go only poly on the trans. like i said to the OP, do ALL or ONLY engine. while your in the groove might as well get the trans done to tho.

elitecamaro94

so what you guys are saying is if you get poly trans and engine mounts then i should be fine and not have vibration? I just had the trans mount done and i just got the stock replacement. My car is a daily driver so i want it to be as smooth as it can when im driving to work or on a weekend cruise.

2000GTP

From what I have gathered, when both the engine and tranny mounts are converted to poly, there is less a chance for vibration. If you are that concerned about it though and want to keep smooth daily driver, why not just stick with the factory rubber mounts for the engine as well?

elitecamaro94

that's what i was thinkin about doing just wanted to know if i can get stock replacement cheaper than what this shop wants to charge me at 125 for the driver side motor mount

2000GTP

Maybe try a GM wholesale parts supplier for the mounts: http://shbox.com/1/4th_gen_tech2.html#Dal_and_Jason

ssbowtie1

Interesting that you were supplied bolts for the pass side. I was only supplied zip ties. I think that's why you had to grind the heads on the bolts down. Here's a picture thanks to Tim @ "http://www.pharmacy.arizona.edu/staff/wunz/myz28mods.html"




EDIT: I think I see what you did. Instead of using the zip ties you used the two bolts that you're supposed to use here:

Don 97 SS

This may or may not be a problem with some engine tranny/combos. I ran a poly tranny mount with oem engine mounts for years on my 97. I went all poly three years ago with the install of the stroker engine.

I'll also add, that I have a (425rwhp) 454SS truck built for the street/towing that has worked fine for years with a poly mount and rubber engine mounts. Maybe the TH400 tranny is tougher in more ways than one.

But the advice for running an oem or one step higher durometer rubber tranny mount might be smart.

Gtpguy

SSBowtie, you saved me some headaches. I had no idea what the supplied zipties were for. Now it makes total sense and I don't have to pay a shop to grind down bolt heads.

caldercay

On the driver's side, I didnt split the clamshell's two pieces completely
apart - I only opened one side of the shell (the right-side in your pic).

EDIT: in hindsight, it doesnt matter that the clamshell is bolted shut (what
I did on the passenger side), since the mounting bolts will 'bolt it shut';.

kgkern01

So other than assembling the mounts, how long of a job should this be with long tubes? 1-2 hours? I have a set of solid Moroso mounts that are waiting to go in with my poly trans mount and just wondered how much time to allow myself to do it.

caldercay

Had I used the zip-ties it would have taken 10 minutes less time. But,
all in all, for me, it took 20+ minutes to do each engine mount and a little
over 2 hours for the Kooks.

kgkern01

I've already got the Hooker LT's installed, just didn't know how much they would be in the way of swapping mounts and how long to swap the mounts out.

ssbowtie1

Did you have to grind away 2 of the corners of the poly mount so you could reinstall the bolts to the k member?



This pic shows how the corner of the mount impedes on the bolt hole.

caldercay

You know what - I did have to "grind" the corner of the mount, but I cant
remember if it was because of that bolt. Not that I ground it, but I used a
very sharp knife to whittle away the clearance that I needed.

I did the "grinding" while the mount was in place, because I think that
the upper "u-shaped mount" (that is bolted to the block) was hitting on
the urethane as I slowly lowered the engine down to mate with the poly.

I have somewhere to run right now, but I can take photos of the final
install a bit later, if it's helpful.