big block transmission brace different?

[folkenheath]

I did a search and can't find the answer. I am swapping from a 350 to a 489 I just built. I have a TH400 (I rebuilt that last year). Anyway, the braces that go from the converter cover to the plates between the engine mounts and the block, is there a completely different setup for a big block or are they the same? Because the plate is actually hitting the block near one of the block plugs before it would bolt flat against the block bosses. I could clearance the plate a little and make it work, but it also looks like where the rods mount to the converter cover are too narrow for the big block oil pan? So is the whole setup different for a big block or is it supposed to be the same? Thanks in advance...

 

[nvrenuf]

Afaik, the only difference is w/ or w/o oil cooler.

 

[Capt.D]

I did a swap on a pickup and nothing was different however it didn't have the braces that are on my Jimmy. The dustcover was thin metal and not thick like we have and it didn't have any braces....I ran a built 454 with 38's for 7-10 years and other than learning a 12 bolt doesn't like built 454's and 38's nothing else happened to it....

 

[blueblazes44]

No problems here either. Replaced 383 with 496 without any issues but did not have any braces that you mentioned.

 

[folkenheath]

Wow you guys are quick. Thanks for the replies. So it sounds like you think they should be the same. Has anyone put a small block set of braces on a big block? Or has anyone had a set of both to compare and see if they are the same, such as the center to center width of the brace bolts on the converter cover?

Thanks again.

 

[nvrenuf]

Man, I'm sorry I just reread you post (I thought you were having problems with the bars themselves).

I used sbc plates and bars on my 454 but I did have to do a little re-engineering. Factory, the plates go between the mount and block but that wouldn't work for me because, like you, plate tabs also hit the block. I ended up trimming them up a little to fit on the outside of my ORD motor mounts. After doing this everything lined up fine and the bars bolted right up to my 4spd bellhousing (which should be positioned the same as an auto inspection cover).

 

[folkenheath]

After doing this everything lined up fine and the bars bolted right up to my 4spd bellhousing (which should be positioned the same as an auto inspection cover).

Could you please measure how far apart the bolts are on your bellhousing that the two bars mount with sometime? I just want to make sure we are dealing with the same dimensions on the bellhousing. I can make the plates work pretty easy with a ball pein hammer and/or a grinder. But I don't know if the bars will clear the oil pan even if I do. Although I could make a flat bar that bolts to the inspection cover and allows me to bolt the braces to that, albeit a little farther apart. I have a moroso oil pan, but it's a deep sump, not a kickout, and I don't believe it's any wider than the stock one. Thanks again.

 

[nvrenuf]

I'll try to get under it tonight to do some measuring and take a pic. I'm currently using a stock pan that I believe I remember having tapered corners to clear the bars. On my old motor I had a deep Canton pan and the bars wouldn't clear the squared corners on the sump/belly.

 

[folkenheath]

Thanks, appreciate it.

 

[nvrenuf]

Ok I checked, both my 4spd bellhousing and my th400 inspection cover have the same measurement for the motor mount bar holes - 7.25". I was right, my GM oil pan does have a corner tapered to clear the left side bar.

Before you go too far making things fit, you might try bolting the bars onto the trans cover and then see if they'll come close to reaching the motor mounts.

 

[folkenheath]

Thank you. That sounds like the same measurements as mine too. I ground and hammered the left side mount plate so it fits the block last night. The other side fits no problem anyway. Now I can install the engine later this week (when the new converter arrives) and hope I can get the bars to fit and clear the headers and oil pan. Is there a way you could send that pic to me so I can see if you oil pan is a lot different than mine? It does have a small taper in the back on the left side, but as it get's toward the bottom it turns more into a big rounded corner than a taper.

I appreciate your time.

 

[nvrenuf]

I forgot you can't see the pic I attached, post up your email and I'll send you the pic.

 

[folkenheath]

Thank you.

 

[nvrenuf]

You have mail.

 

[thatK30guy]

John, you remind me of Daryls dog, GTD, always trying to get his mug in the pics.

Notice your forehead in the lower right hand corner?

 

[nvrenuf]

:thud: I didn't even notice that.