Anyone here have a 73-80 with a 700 or 200 trans installed?

[bigblock73]

Just like the title says. I have a 454/700r4 combo in Yeller (originally a 350/th350 setup), but the clearance from the top of the trans and the cab floor is minimal (like 1/2" or less). Does anyone else here have a OD trans in their 73-80...and even better...a OD trans with a big block? If so, can you please post a pic showing the clearance in question...or at least a rough dimension? I have installed everything correct as far as I know, but this just doesn't seem right...there is basically no room to slide the trans back if I wanted to remove it without removing or jacking up the engine. Swervin posted a pic of his on his 85, and it was very similar...but I just would like more opinions.

Here is my setup...

• 454 mouinted in the frame in the same position as the 350 using the same style mounts and clamshells.
• Same engine towers used, and mounted in the same position on the frame.
• Stock 1973 transmission cross member used, slid back slightly in order to bolt up transmission.
• Energy Suspension transmission mount.

Looking forward to hearing what you folks think, thanks for any help.

[Jonboy]

Jeff, I don't remember mine being that close, but I will check when I get home. I ended up doing almost exactly what you did in regards to trans crossmember, but it seems like I can get my hand between the bellhousing and firewall.

[bigblock73]

Originally Posted by Jonboy

but it seems like I can get my hand between the bellhousing and firewall.

Perhaps I should have clarified...I have plenty of room up there (front of the trans)...it is at the rear of the trans and cab floor where the fit is tight. I will look for the pic I posted a while back.

[bigblock73]

OK, here is a thread with the pics I was talking about. I never installed the "BB stands" I purchased, none of the holes lined up in the frame or front cross member. I got a lot of help in this thread, but I still think 1/4 to 1/2 inch is cutting it close. Hopefully you 73-80 guys can get me some visual or numeric proof.

http://67-72chevytrucks.com/vboard/s...t=transmission

[truckinbean]

Jeff, I noticed that on my 77 blazer, when I put in the Energy Suspension Trans. mount it was significantly taller than the stock one. Maybe as much as 1/2" or more. But it could have been because the old one was cracked and worn down. I've never noticed any clearance problems with mine even with the E.S. mount, but I haven't looked that closely. I think the blazers had a bigger hump too IIRC.

[piecesparts]

I have a 700 R4 with a small block and there is more clearance than what you are talking about. I also have a floor shifter and the cable has plenty of room to exit out of the hump and go across the top of the tranny. I am betting that your problem is related to the mounting of the big block in the motor mounts that are the same position as the 350. I haven't really looked but i am betting the big block would set forward a little bit.

[TIMSPEED]

Originally Posted by piecesparts

I haven't really looked but i am betting the big block would set forward a little bit.

Yes.

[bigblock73]

Originally Posted by piecesparts

I am betting that your problem is related to the mounting of the big block in the motor mounts that are the same position as the 350. I haven't really looked but i am betting the big block would set forward a little bit.

I am not so sure I can agree with that, here is why. In a side by side comparison with the BB stands I purchased (compared to my stock small block ones)...the mounting holes (on the stands) didn't move forward or backwards very much...if any at all, between the two of them. The BB stands also did not line up with any holes on the frame or front crossmember...leading me to believe they were pulled off a different frame dimensionally (perhaps a 3/4 ton?). Also, lets just say the engine is in fact too far back and needs to move forward...it would have to come forward quite a bit to give me more clearance since the trans tunnel and trans tail housing have a very similar slope to them. If I moved everything forward an inch, I would probally only gain a 1/4 inch or so (guesstimate). I am not trying to disagree to be difficult, just trying to approach this from all angles and possibilities.

Thanks for all the help so far, please keep your ideas and thoughts coming...as I will have some studying to do (on this) when I get off work tonight.

[bigblock73]

On a side note, does anyone know the dimensional differences between a th350 and a 700r4? Looking for length and height differences. A diagram would be most helpful.

[1974gmc]

my truck has a small block with th350 and there is only like 1/2-3/4 of an inch

[SanitysBane]

Well im an '83 guy, but on my truck heres the story. When we put in the 454(with 305 towers in the stock location) and the 700R4 we still have a lot on clearence, im not shure but i know its over 1/2 inch, could the transmission tunnel it self be differnt? I don't know anything about '73's so I don't know if they are interchangable or not, just a thought. As far as the trany being to far back on the big blocks and small blocks both it is the exact same demension from the bell housing up to the motor mounts.

[Captkaos]

I still stand on my opinion that you are fine with that much clearance. BTW, Tom has a '79 with a 200R4 in his pickup.

[Captkaos]

Originally Posted by bigblock73

On a side note, does anyone know the dimensional differences between a th350 and a 700r4? Looking for length and height differences. A diagram would be most helpful.

Length overall:
TH350 6" tail - 27 11/16
TH350 9" tail - 30 11/16
TH350 12" tail - 33 27/32
700R4 - 30 3/4

Bellhousing the CL of mount:
TH350 - 20 3/8
700R4 - 22 1/5

[1FaastC10]

Originally Posted by Captkaos

Bellhousing the CL of mount:
TH350 - 20 3/8
700R4 - 22 1/5

i have yet to see a tape measure with 1/5 incriments.

[N2TRUX]

Jeff,
Didn't you have some issues concerning the correct way to mount the body bushing? Did you ever get that corrected?

[Lynx]

Originally Posted by 1FaastC10

i have yet to see a tape measure with 1/5 incriments.

Ive got a tape and ruler in my tool box at work like that! They are the wost things i have ever seen. I do like having fun with them tho by asking people to read a measurment for me!

[CbHeEaVsYt]

is there any difference in the cross member from 73 80 to 81 87? maybe u could change the cross member and maybe thatll work for you?!?!?

cb

[bigblock73]

OK, here is a side by side comparison of the stock "SB" stands that came on Yeller, and the BB stands I purchased from another board member who swears they are out of a BB powered truck (year unknown, but a 73-80). There is clearly a difference, and wheter or not this related to my trans clearance problems is still up in the air. If I remember correctly, the BB mounts did not line up correctly on my frame, but when I get home tonight I am going to double check...maybe it was the mounts that didn't line up with the stands?? I honestly can't remember. Also, it is odd that the used Hooker headers I purchased that were supposed to fit all 73-87 BB powered 2wd trucks would not clear the transmission crossmember (the collector openings were lining up centered on the crossmember, and about 1/2" too long, not allowing me to bolt up the flanges to the head).

[superchevy]

I just went out and snapped a couple of pics of the mounts in my '77 C20 454/T400 that I swapped the 461/700R4 into. These are the original 454 towers that came with the truck, with the correct big block (not small block) motor mounts attached...2 pics of driver's side and 1 pic of pass side.
With the mounts installed, and using the original crossmember in the original location (my 700R had the "caprice tailshaft housing" which relocates the trans mount location to the original T400 location), I would say I had 1"+ worth of clearance at the rear of the trans...I never measured, because it never looked like a "tight" fit to me...in fact, I slid the trans back from the motor (with the fluid lines, tv cable, speedo cable, etc. still attached) enough to change the flywheel (4" at least).
I also had no header clearance issues whatsoever, and that was using the long tube ones.
Don't know if this will help or not, but thought it might give you something to use.
SC

[swervin ervin]

Jeff,

I can't remember now it's been so long, but did I tell you I removed the spacer that comes with the Energy Suspension tranny mount to gain clearance when I put in the dual hump crossmember on the 85? When I put it in with the metal spacer I had with the original crossmember it was too close to the tunnel. I used the mount without it and all is fine.

[Bob Moore]

BigBlock73 - Which is which? The clean stand is big or small bock????

Thanks - Bob

[bigblock73]

Originally Posted by Bob Moore

BigBlock73 - Which is which? The clean stand is big or small bock????

Thanks - Bob

The one that is painted (clean) is the small block stand, the other one is the BB stand I purchased.