Can I use big block stands with a 406 in my '68?

Boucher421 · Feb 19, 2013

I was researching crossmembers, and saw this one for sale on eBay:

http://www.ebay.com/itm/Camaro-Fire...Truck_Parts_Accessories&fits=Year:1968|Model:Camaro&hash=item53f42221ce&vxp=mtr

Notice it says 'cnvt' in the description. I think the one I purchased had that in the title too. The eBay description goes on to say, "This reproduction crossmember works for small block V8 convertibles with either a TH350, Powerglide, or manual transmission (no Big Block, Coupe, or TH400)."

Is there really a difference between convertible and coupe crossmembers? Only thing I could think is that a convertible needs more frame support than a coupe? Doesn't really make sense to me.

freezined · Feb 19, 2013

There's no difference in SB crossmembers between hardtop or convertable that I know of.

You could slide your subframe forward, but you won't get more than about a 1/2 inch. With the linkage off the transmission does it fit side to side? I agree on using 69 and later shifter mount. Can you slot your crossmember or tranny mount to adjust for the difference in length?

Boucher421 · Feb 27, 2013

I measured the crossmember and the holes were 1/4" off from being centered. I flipped the crossmember around (so the three holes are now on the passenger side), and the left/right alignment now looks ok (fore/aft still a bit off).

Holes on passenger side means it's backwards, right?? Any thoughts??

TJS69 · Feb 27, 2013

Yes, The crossmember should be tapered down a small amount,at the rear of the crossmember also. By reversing it must be showing how bad the repro crossmembers are, because the bolt pattern should be centered, meaning it should be the same both ways.

I thought you were just going to slide the crossmember back as your bell housing was too long and you needed a new driveshaft anyway.

Boucher421 · Mar 4, 2013

TJS - I gotta laugh at your comment "just slide the crossmember back". You make it sound so easy!! I have an knack for taking something that SHOULD be simple, and turning it into a three month project.

Rather than drill holes in subframe to move the crossmember back, I figured I'd just increase the size (or drill new) of the mounting holes. Even if that gets resolved, I still have the shifter clearance issue.

I got the hurst install kit for a '69 Camaro. It brought the shifter FURTHER back, so now it won't even go through the tunnel! I think I'm at one of two options:

1. Find a hurst shifter/install kit that'll bring the shifter forward an inch or two. Anyone know if this exists?

2. Cut the tunnel hole back an inch or two. It seems I would need to drill a couple extra holes for the installation of the console. Will this lead to other figment issues?

Not sure if I should be starting a new thread. The last couple pages are a bit off from the original threads topic title.

TJS69 · Mar 4, 2013

No, don't start a new thread. It will only "rehash" everything that is in this one. There is not enough material on a stock crossmember to do what you are thinking.

I said "just slide it back" because it is only moving about 3/4's of an inch, and people who have converted to 700r4's have slid it back 2".

Your shifter is a big problem. Did you use a small block kit or a big block kit ? Remember the big block kit will move it "back" 3/4's of an inch and to the driver's side by 1/2". ( The shifter is moved opposite of what the big block engine mounts and transmission crossmember do, to bring it back to the small blocks position)

You said that you have some type of an engine plate mounted between the engine and your bell housing. I believe that is causing some if not all of your problems. Yes, it may only be 3/8's" thick, but whatever it is bolted to is not allowing the engine/trans to move forward.

That plate is not really needed, anyway.

TJS69 · Mar 4, 2013

I am not sure what angle carburetor should sit at. I believe it is close to level, but I could be wrong.

I believe that engine plate is keeping the engine from tilting. I realize that this is an old picture and it may not be sitting like that, now.

flat350 · Mar 4, 2013

There is a member on here "Crashent" that makes a mount to use a 69 Hurst shifter on the 764 tailshaft Muncies(they are further back) it locates it in the tunnel hole correctly.Maybe the same mount would solve your problem,do a search for his name and you should get an e-mail for him,it can't hurt to ask.I do have a phone # and e-mail for him some where in the garage if you can't come up with it.I have a 68 BB mounts/SB engine/BB cross member/67 console/764 tailshaft trans and he says his mount will put a 69 shifter in correct place in the tunnel hole

Boucher421 · Mar 5, 2013

TJS - here's a better pic of the plate. It's only about an 1/8" thick. It'll get me closer, but not all the way. Also, if I remove the plate, the flywheel will be open to the elements. Is that normal?

http://i1080.photobucket.com/albums...r2011/EB008B71-CC3F-4A59-BF00-B33A6F4695F4-366-0000001F69004145_zpsf2330a46.jpg
http://i1080.photobucket.com/albums...r2011/ECD98C7B-B0F2-4460-A427-6D66F9EC31BA-366-0000001F77EA221D_zps545b4543.jpg

Also, regarding drilling out the crossmember, wouldn't it be safe to drill out the holes almost all the way to the edge? I know it would sacrifice some of the structural integrity, but I wouldn't think the piece is under so much pressure that it would be at risk of breaking/bending:

http://i1080.photobucket.com/albums...r2011/F83479C7-9DF6-40E6-9892-FA53FE493D33-366-0000001F51C8E1FA_zps2a6e8614.jpg

When you say "slide back", confirm that you mean drill new holes in the subframe?

Carb looks pretty level. Picture angle makes it look off.

I don't see install kits that differentiate between big and small block.?.?.?

Boucher421 · Mar 5, 2013

Flat350-

What drove you to use BB mounts with a small block? Did you have other fitment issues later on? I really don't want to go down that road, but I do have BB stands/mounts in my garage.

I'll look up crashent. You said the 764 tails are longer...by how much? Do you know of other tails that are longer?

TJS69 · Mar 5, 2013

That engine plate is at least 1/4" thick. Does the plate bolt to the firewall ? If it does, it is pulling the engine back on it's mounts not allowing you to bolt up the transmission. It may even be holding it to one side or the other. Unbolt it and put your transmission crossmember in. You should be able to raise or lower the tail of the transmission, which will also change your bolt hole locations some.

That plate will make everything solid and not allow any movement at all and increase vibrations etc. Those are only needed in Race Cars or Very High horsepower applications.

It is not stock and however it is mounting to the body or frame is probably wrong.

The bottom bell housing cover on Chevrolets only bolts to the bottom of the bellhousing and does not add to the transmission length.

flat350 · Mar 6, 2013

Boucher421 said:
Flat350-

What drove you to use BB mounts with a small block? Did you have other fitment issues later on? I really don't want to go down that road, but I do have BB stands/mounts in my garage.

I'll look up crashent. You said the 764 tails are longer...by how much? Do you
know of other tails that are longer?

I'm not recommending that you follow my example,my car is a Frankenstein.68 BB mounts/BB crossmember/SB engine/long water pump/67 console/71 Chevelle Muncie.Some of it came with the car and some was priced right to allow for modifications.

Most everything worked OK with the Saginaw trans that came in the car,Hedman headers fit good,HEI dist cleared the firewall,don't remember what I used for a fan shroud but i found one that fit at a swap meet.The problem now is more mods to make the 71 vintage trans work,input/output shafts different,new drive shaft,shifter mount,trans yoke........I can make what I have work with some time and scrounging but i knew things would not fall together with the odd mix of parts that I have

I think some of the advice given above is good,I'd start with removing the motor plate,it seems things snowball too much.The money you've spent on crossmembers,shifters and oil pans could have gone towards a stock type bellhousing and with the plate gone and a stock housing you would be at the correct starting point to get things to line up correctly.As far as the shifter goes are you sure the car was a factory 4sp car and that the cutout is in the correct location.

I'm not an expert on transmissions the 764 tailshaft is 11 1/2" from the mating face at the trans to the end and the top single mounting lug is 4" from the rear,and I get 22" overall front face to rear

Boucher421 · Mar 6, 2013

The plate is NOT mounted to the firewall. My mcleod bellhousing is 6 1/4" deep. That seems to check with a stock measurement from another setup. The motor plate is only half of the plate that appears in the picture. It measures just barely over 1/8". I'm not stuck on removing the SFI motor plate, but I just want to make sure that:

A) the motor plate is my problem, and
B) removing it will fix my problem.

I would think mcleod manufactured their replacement bellhousing to match up with stock height/depth specs, even with the plate (I don't think the 8630 model comes without the plate).

All that being said, I completely agree that removing the plate will bring everything 1/8" forward. I just don't think it's enough.

TJS- do you really think slotting the crossmember holes further back is a bad idea?

Flat350- even if I wanted to follow your path, I only have about 1% of your know-how. I'm pretty sure it was a 4 speed. The tunnel hole has a reinforcement on the bottom side. Other than that, how would I know?

TJS69 · Mar 6, 2013

The plate may not be ALL of your problem, but it is some of it. An engine plate that was only 1/8" thick wouldn't do anything. It would bend or tear very easily. That plate looks to be about 3/8" thick and I said 1/4" to be safe. Again, there is not enough material on the crossmember. (I have one next to me as I type this) There is only 1/4 to 3/8 of an inch of material beside the holes. You have to look at this by what is correct, and what is not stock. Everything is correct except that plate and your bell housing. Moving your crossmember back is only a band aide fix. Your shifter is still too far back, and you would have to enlarge the hole and/or move your console back.

Boucher421 · Mar 6, 2013

Here's a couple bell housing pics. The 'plate' is actually two pieces mated together. McLeod Racing assured me their product did not add length to the bell housing/drivetrain. I'm hoping guys can chime in with their bell housing length measurements.

http://i1080.photobucket.com/albums...2011/CFB4C199-C0EE-4E6F-BDDC-21F3DAF533AF-1000-000001A47798CF47_zps6089d1dd.jpg
http://i1080.photobucket.com/albums...2011/B18F1442-743D-4BDA-B586-B5DCCFF93AB6-1000-000001A481AAB238_zps2ff3312c.jpg

Working now to find a mount for the shifter to bring it forward.

Any problems with moving the console back an inch or two (if that's what it comes down to)?

TJS69 · Mar 6, 2013

Yep, You are correct in saying that the plate is only 1/8" thick. No, I wouldn't enlarge the crossmember holes. That isn't going to fix your shifter problem. A stock bell housing from engine face to transmission face is supposed to be 6.29 inches. We probably should get a dimension from the front of the block to the core support to verify that the engine needs to come forward.

Here are dimensions that should be close for you. These are from 1969 302/350 stands.

Boucher421 · Mar 6, 2013

That's gonna be tough:

http://i1080.photobucket.com/albums...2011/B25383CA-AC80-4086-BAFD-67A96F198556-1000-000001A9D69C87C2_zpse3b99451.jpg

TJS69 · Mar 6, 2013

I thought of that after I had posted it. Maybe you can find a place on the frame or something and I can measure mine.

TJS69 · Mar 7, 2013

Here is the one measurement you should be able to get. Measure from this vertical surface on your firewall to the center of the carburetor pad. Use a square and a level to get as accurate as you can. A tape measure's end hook is usually loose and can give about 1/16" of error. This measurement should be 12 5/16" within about 3/16".

If the engine needs to come forward you can drill new holes in your frame stands as shown. If you do this make sure your clutch z-bar will work. Some other things would be the carbs. throttle rod and where your fan enters the fan shroud. (when you get that far) and Header to exhaust connection. Also if you are using a mechanical fuel pump, make sure that it won't hit the frame.

You really shoudn't have to do this... as something is wrong. Maybe it is reproduction framestands ?

Boucher421 · Apr 9, 2013

Those measurements were spot on. I gave up and extended the holes in the crossmember. 1/2" back and a 1/4" towards the passenger side. Not the 'elegant' solution I was looking for...but I needed to make some progress after six months. (I only get one day every other weekend to work on the car.)

I'm guessing ill be dealing with the fallout from here out.

Thanks for all the help.

Can I use big block stands with a 406 in my '68?

Boucher421

freezined

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TJS69

Boucher421

TJS69

TJS69

flat350

Boucher421

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TJS69

flat350

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TJS69

Boucher421

TJS69

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