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DragCat

Transmission crossmember ?

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I read in another thread that with increasing HP (i'm dropping in a bigger crate) that the crossmember should also be upgraded to a chevelle part. Is the suggestion just a regular Chevelle crossmember or something a little more beefy like this? 

https://www.ss396.com/mm5/merchant.mvc?Session_ID=75881b1ab9bf1b5f88375433ed613c5f&&Screen=PRODB&Product_Code=FCM-RCAE&Category_Code=chevelle-crossmember

 

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Ok, depends on how you want to go. The reason for replacing the factory Monte Carlo crossmember is due to the rubber isolators at the ends of it. Through time they tend to rot out the crossmember there. With a high horsepower car it usually pulls the crossmember out of the rubber and feels like a broken motor mount when accelerating. 

The reason for the Chevelle crossmember being used is that it used to be readily available and the only thing that fit and bolted directly to the frame. No aftermarket crossmembers back then. Lolol

The one you have pictured is a great piece. I have one in my 70 SS. It will take whatever you throw at it horsepower wise. It is a heavy piece tho if you are looking for weight savings. 

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The stock (reproduced) Chevelle ones look a lot straighter than the MC ones, at least in the exhaust pipe area, unless I'm looking at them wrong. Have you seen that in your experience Tom?

https://www.opgi.com/chassis-suspension/bushings-mounts/1968-72-transmission-crossmember/crossmember-transmission-1968-72-chevelle-ch28177.html

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I believe the reproductions of the Chevelle crossmember is not as bent as the originals like you have stated. 

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4 hours ago, MC1of80 said:

Ok, depends on how you want to go. The reason for replacing the factory Monte Carlo crossmember is due to the rubber isolators at the ends of it. Through time they tend to rot out the crossmember there. With a high horsepower car it usually pulls the crossmember out of the rubber and feels like a broken motor mount when accelerating. 

The reason for the Chevelle crossmember being used is that it used to be readily available and the only thing that fit and bolted directly to the frame. No aftermarket crossmembers back then. Lolol

The one you have pictured is a great piece. I have one in my 70 SS. It will take whatever you throw at it horsepower wise. It is a heavy piece tho if you are looking for weight savings. 

Thanks Tom, I don't plan on running any NHRA Stock Eliminator classes so i'm not really worried about the weight lol. Is that just a bolt in or are there some mod's that need to be addressed?  I'm assuming the part the Joe linked would be satisfactory, just a bolt in replacement without changing out the rubber insulators? 

As with any build i'm learning a lot and questioning more lol. I plan on having fun with mine, and yes pushing it hard down the track so I want to do it right the first time. The great thing about this forum is the amount of info available in all formats, on the down side of course the I wasn't expecting I needed one of tho$e lol. But i expected the unknowns and its just part of the deal. 

On a side note i'm jealous of your black carb fuel line on the SBC to BBC 489 post lol. I went with the black from the fuel pump but couldn't find any in black for my carb that didn't have negative or complaints about leaking fuel. I went with the blue/red, guess only i'll know once the air cleaner is on.

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Hey Mark. Using the Chevelle crossmember deletes the Monte Carlos rubber mounts. It bolts directly to the crossmember. 

The G force crossmember bolts directly to the frame also. I did not have to modify it in any way. Bolted right in and gives you great exhaust clearance. You can tuck your exhaust up close to the floor if you like.

Thank you for the compliment! The black carb fuel line/log took awhile to find. I believe I bought it from summit. 

IMG_0036.JPG

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Thanks Tom, i'll have to mull it over lol. Altho I don't want to spend the extra coin i'm leaning toward the G-Force at the moment. Just looks beefier (if thats a word lol) 

I tried Summit, but there were reviews of leaking and I don't mess around with possible fuel leaking problems. Funny thing with a Holley Carb I went with Edelbrock fuel lines. 

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You could always just weld a couple of tabs on the stock crossmember as I did to get 4 mounting bolts to fasten it solid to the frame. You'll have a lot less drama than I did if you're  keeping the T-400 trans.

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G Force is cool, but it is heavy. Plenty of stock Chevelle crossmembers out there. And I am never a fan of Chinese built repops. I had a customer job split the weld on the tabs where the tranny mount attaches. Car was a 72 L48 Th350 Chevelle. Found him a proper used one off Craigslist for $50 local.

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9 hours ago, jft69z said:

You could always just weld a couple of tabs on the stock crossmember as I did to get 4 mounting bolts to fasten it solid to the frame. You'll have a lot less drama than I did if you're  keeping the T-400 trans.

My plan was to keep the original 400 and i'm taking mine to the transmission guy tomorrow for the rebuild. Of course now I have added my cracked bell housing to my list of issues. Tomorrow will tell. I'm just trying to figure out my options and getting feedback from those in the know, oh yea, I don't weld 🤣

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On 2/14/2020 at 7:36 AM, Andy's Auto said:

G Force is cool, but it is heavy. Plenty of stock Chevelle crossmembers out there. And I am never a fan of Chinese built repops. I had a customer job split the weld on the tabs where the tranny mount attaches. Car was a 72 L48 Th350 Chevelle. Found him a proper used one off Craigslist for $50 local.

So are you saying to search CL or similar instead of going to the suppliers like OPGI and such? I'm rethinking the g-force idea, I don't think I need all that 

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On 2/16/2020 at 6:54 PM, DragCat said:

So are you saying to search CL or similar instead of going to the suppliers like OPGI and such? I'm rethinking the g-force idea, I don't think I need all that 

When it comes to structural metal on any Vietnam War era hot rod, 50 year old Buffalo steel is better than Chineseum any day of the week. 

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1 hour ago, Andy's Auto said:

When it comes to structural metal on any Vietnam War era hot rod, 50 year old Buffalo steel is better than Chineseum any day of the week. 

Bethlehem Steel in Lackawanna, NY. About 30 miles from me :). Lot of good jobs back then when the place was open.

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