Had a 350 now a 455 what motor Mounts to buy?
 

I have a 68 rag top that had a 350,Ive built a 455 and I will need new motor mounts after it comes back from the dyno. What motor mounts should I order to fit the frame mounts? Thanks In advance

Same ones should work fine in this case.

So I should be able to buy a new mounts for a 350 and bolt them up . Thanks

All the A-body Pontiac V8 mounts are the same from '64 -'72, you're good to go.

There were some special wider '70 -'72 455 mounts for factory 455 installations, but they're not needed. Plus they won't work with non-455 frame brackets, which are rare and pricey.

check out MityMounts, they are $$$ and supposed to be good, utilizing a interlock between the metal parts in case the rubber fails.

What Ive noticed: most of the stock replacement motor mounts and transmission mounts are made in India using some kind of rubber isolater that seems to disintegrate in about 5 minutes. I started seeing those cheapo mounts over 10 years ago. I dont know if the currently available mounts are better or not.

OB1KUBOTA,
I also have a 68 LeMans rag top. I put a corporate 10 bolt rear in it last winter and the whole suspension has been redone. I plan to put a 200-4r in it this fall and then I have a 73 455 I want to rebuild next spring and put in next winter. What trans did you go with and did you learn anything I should know about concerning replacing the 350 with the 455? Any advice before I start mine? Thanks

Other than upgrading the strength of the trans and rear end for the 455 (you do plan to use the extra power, right?) and upgrading the cooling system to handle the bigger-cube engine (bigger radiator, or an aluminum one), there's really no difference between installing a 455 in place of a 350.

The 2004R trans will need the clutch plates replaced more often when used behind the high-torque 455. Personally I'd recommend the 700R4, it's based on the stronger TH350 unlke the 2004R that based on the weaker TH200.

The 455 weighs only a scant few extra pounds more than the 350 due to the slightly heavier long-stroke crankshaft (3.75" stroke for the 350, 4.21" for the 455), so no suspension upgrages are necessary due to any real weight difference.

The same accessories and exhaust will work for either engine, this swap couldn't be easier.

Thanks B-man. Any clearance issues with the 700R4? I seem to remember some posts about having to modify the floor pan. This was one of the reasons I was leaning toward the 2004R. I did talk to Don at Transmision Specialties in Addison, IL. He also recommended the 700R4 but wasn't too familiar with the Pontiac floor pans. Anyone have any experience with Transmission Specialties?? They are the only racing transmission shop I can find near Chicago and I'd sure like to buy one where I can walk in and ask questions after the fact.

The 700R4 shoudn't require any tunnel mods.

I know the 4L60E and 4L65E (electronic versions of the 700R4) requires a few dimples in the tunnel right where the bellhousing bolts to the trans case due to the constuction of the case, big bolt bosses in that area. I'll be bangin' on my '64 Tempest in that area soon, I'm putting a 4L65E in it.

The 700R4 doesn't have that feature, the main case is one piece.

Wheelspin (Les) here on PY has a 700R4 in his '66 GTO if I'm not mistaken, you could send him a PM and see if he had any issues.

Anchor has a good product from what I've seen working at a parts store and can be bought over the counter for many applications. At the store I worked at we kept most of the GM, Ford, and Chrysler V8 stuff in stock.

You might want to read this post about mity mounts being the cheapo india / korean mounts with the country of origin and part # ground off and a extra bolt installed to limit their movement. With a much inflated price and evasive answers when questioned about where the mounts are actually made, It isn't in the U.S. as they would have you believe by their advertising. Post # 20 sums it up pretty well. Here's the link:
http://forums.maxperformanceinc.com/...ty+mounts+made

Thanks for all the suggestions guys. Glad to know about the mighty mounts. For use on a 455 with Kauffman heads, what features should I insist on in the 700R4 rebuild?

B-man, the adapter plate required to put a 700R4 on a Pontiac doesn't move the trans back enough to cause clearance problems does it?

The adapter plates are pretty thin, 3/16" or 1/4" so it's not a big issue.