Aftermarket Crossmember Help - First Generation Pontiac Firebird (1967 - 1969) - Firebird Nation

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Aftermarket Crossmember Help


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5 replies to this topic

#1 Martin Cooper

Martin Cooper

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  • Engine: 326
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Posted 11 May 2020 - 08:01 AM

Does anyone have a good suggestion for a transmission crossmember for a first gen convertible with a TH400 or 200R4 that will allow for original routing of the exhaust system above the body stiffening plate?

I am installing a 200R4 in my 67 convertible. I have a G-Force crossmember that fits the frame and transmission like a glove but there is absolutely not enough space at the rear of the crossmember to route the exhaust system. My Flowmaster exhaust system was a perfect fit with the original crossmember and trans.

#2 fourthirteen

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Posted 18 May 2020 - 04:09 PM

Are you still using the original body stiffening plate? I’m surprised you had room above it for a Flowmaster exhaust system unless it was a transverse muffler system.
Anyway, you can get aftermarket stiffener plates that have more drop to them that may give you a little more room.

#3 Martin Cooper

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Posted 19 May 2020 - 03:01 AM

I am using the original stiffening plate. I also understand that Hotchkiss makes an aftermarket plate that allows more room for the exhaust. My problem is space between the crossmember and where the exhaust narrows from either side to fit into the driveshaft area. I have since purchased another crossmember from Heartbeat City that is designed to accommodate a TH400 in a small block Camaro. It appears that the exhaust will work but it seems to mount the trans too high. I'll figure something out. Thanks for your input.

#4 Martin Cooper

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Posted 08 June 2020 - 01:41 PM

I've decided that using the G-Force crossmember I bought initially will be the one I use. Unfortunately I have decided that I will have to re-route my exhaust system.
I had also purchased a crossmember from Heartbeat City that was designed to install a TH400 in a small block Camaro. It is a very well made component and I bought it because many crossmembers that I considered stated they were for TH400 or 200R4. This one could NOT be used with a 200R4 because it contacted the trans pan would not allow good securing of the transmission. I would highly recommend this product for anyone planning to install a TH400 in a first gen Firebird that was not originally equipped with the TH400.

#5 fourthirteen

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Posted 09 June 2020 - 10:27 AM

Too bad you have to re-do the exhaust and you wasted time with the Heartbeat City crossmember. Well at least you got it worked out.

#6 Martin Cooper

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Posted 09 June 2020 - 11:01 AM

Right, I think it's all going to work out fine even though I spent unnecessary time and money. Such is the case with custom installations.




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