HELP Didn't fit! My SBC to BBC swap.

[68_chop_top]

I have read this site for a number of years. Built my 68 chop top. Started with no motor or tranny. Found a 68 327 block and went from there. A 5 speed TKO runs great. Got the bug for a big block and started collecting parts and reading up. I was told there are two kind of frames. An automatic tranny and a manual tranny frame. I was sure I had the manual frame so I went with the TKO 5 speed. Had to get the correct bell housing with mounts to fit the cross member. The engine and tranny make up a four point cradle.
So when I was thinking on big block, the bell housing fits the engine and made up the rear mount. Bought big block motor towers from someone off this site. Bolted to the motor and to the frame using the rear two holes and crossover hole. Thought everything was set so I grabbed a head for the driver's side and NO GO. The head hits the cab fire wall where the gas pedal mounts to and the clutch rod comes through the wall.
How can I use the forward two holes with the bell housing anchored in the rear?
I thought I had done my homework and now I am grounded!
Someone please tell me where I went wrong.
Thanks in advance for your time.

[454stepside]

big block motor stands bolt into the front two holes otherwise the motor will hit the firewall as you are experiencing

[68_chop_top]

But then the rear bell housing mounts won't match up?

[454stepside]

you will have to move the cross member forward also and then your shifter hole in the floor will be off also

[BossHogg69]

68 chop top - I have this swap in my '69 but my truck was originally an auto. I originally used the stock auto trans crossmember, but when I began my frame off, I used a GMC Paul's auto crossmember, but I had to modify the transmount on the crossmember, because of the way the casting on the TKO is. I'll post up pics so you can see what I mean, if you need others, let me know, I have a ton that I took during disassembly. Fwiw, I used a GM '621' bellhousing off a Muncie.

[68_chop_top]

Thanks Boss for the pictures. I have read this site for years and never heard I had to move the bell housing cross member. I too have made a tranny cross mount for my TKO. The original granny 4 speed just stuck out in space hanging off the tranny, no support.
I can't believe I have to pull that motor out and cut that tranny cross member out.
Oh well, if it were easy . . .

[LockDoc]

-
If you use the big block side mounts and rear transmission mount do you even need the bell housing cross member? I don't know that much about the big blocks with a manual trans but I wouldn't think so...

LockDoc

[BossHogg69]

Originally Posted by LockDoc

-
If you use the big block side mounts and rear transmission mount do you even need the bell housing cross member? I don't know that much about the big blocks with a manual trans but I wouldn't think so...

LockDoc

I don't have a b/h crossmember either. Just the motor mounts and the trans x-member in the pic.

[68 TT]

I had to remove the manual trans bell housing mount crossmember from mine but didn't measure how much I moved the engine.

I put the engine in and pushed it forward just enough that I could run my tall valve covers and get them off without having to pull the mount studs off first.

The square body clam shell motor mounts & stands really help with header clearance and they are strong enough to hold up to a big block too.

[68_chop_top]

I will still have to remove the bell housing cross member because of clearance issues. Moving the motor forward will mean the tranny will have that b/h cross member by it.
So should I totally remove the b/h cross member or move it forward to match the amount I move the engine forward. Looks to be about 4 inches. Are there holes in the frame for the b/h cross member?
What did the factory big block and manual transmission set up have?

[Muskey]

Hey Bosshog the pictures of the motor stand and motor mount,what year are the stands from? I'am switching from a sb to a bb

[BossHogg69]

Muskey - they are '72 stands & clamshells

68_chop_top, if it were me, I'd take out the b/h x-member and go with a traditiontal motormount/trans x-member setup.

[jocko]

It does seem odd (and counter to the "more must be better" theory) - but for any mounting set up - you should never have 3 longitudinal mounting points in an engine/trans line (i.e. engine mounts + bell housing mounts + trans tailshaft mount) - it should only be the eng mounts + either the bell or tailshaft mounts. Using 3 mounts potentially could cause binding - maybe not, but it's certainly not necessary or required to add mounting points. This is why old cars that had the bell housing mounts did not use tailshaft mounts - and newer vehicles with tailshaft mounts have no bell housing mounts. Many folks going from the old mounting setup to a newer trans assume they need to both use their original bell mounts AND use the tailshaft mount location simply because it's there - but that is not the case. I went thru the same dilemma when I swapped in my T5.

In your case, I'd have to agree with Boss Hogg - if the bell mounts are not in the way, leave them, but don't use them and add a simple tailshaft mount. If they are in the way, remove them and then still add just the simple tailshaft mount.

Should be much easier shouldn't it! I about pulled my hair out with my T5 and the bell mounts, but at lease I wasn't swapping to a big block at the same time. Bottom line is mount the engine so it doesn't hit the firewall, skip the bell mounts, and then add a simple tailshaft mount wherever it ends up needing to be.

[68_chop_top]

In talking with a friend of mine who has had more 67-72 trucks and swapped any and everything into them, he told me to put the motor mounts in the front holes and to move the b/h crossmember forward to their holes. That is the way the factory did it. Went out today and pulled the short block out and looked at the crossmember. Sure enough there are pre-drilled holes to move the crossmember forward.
Why didn't I read about this before hand.
Oh well, minor set back.
They say experience comes from mistakes.
I am wiser tonight!

[68 C10 402]

68_chop_top, can you tell me if you got this set-up to work? I have a 68 that was originally a straight 6 and I am trying to install a 402. I got a set of the original frame front mounts but having a hard time with the b/h mount. The original one in the truck was too far back and due to the design could not be moved up as you suggested. I then found a 72 with a small block and manual and grabbed the b/h cross member out of that. This allowed me to bolt everything up but the angle of the engine is way off – tilting the tailstock of the transmission down. If I try to level off the drive train I have about 1.5” gap between the b/h and the x-member mounts. I have been told that there is actually a 68-71 manual transmission x-member specific to the BB but not sure if that is my gap. I am debating going to auto x-member and ditching the b/h version. Wondering if you had any success or if anyone call help me out. Been reading the site for a few years so hoping the answer is out there. I added a few pics for clarity.

Thanks!

[Livrat]

You are correct, there is a BB specific Belhousing mount and is different than a Small block one, It will not work without major mods, I would simply remove your small block one and use an auto trans crossmember

[68 TT]

Originally Posted by 68_chop_top

In talking with a friend of mine who has had more 67-72 trucks and swapped any and everything into them, he told me to put the motor mounts in the front holes and to move the b/h crossmember forward to their holes. That is the way the factory did it. Went out today and pulled the short block out and looked at the crossmember. Sure enough there are pre-drilled holes to move the crossmember forward.
Why didn't I read about this before hand.
Oh well, minor set back.
They say experience comes from mistakes.
I am wiser tonight!

I tried that in my 67 and the big block long water pump 2-groove crank pulley hit the forward crossmember with the motor mount stands in the forward holes. I ended up notching the crossmember for clearance rather than moving the engine back and shortening my driveshaft. Better, more stable design that is less prone to tossing belts at higher RPM.

That is probably why they used the short water pump setups in the trucks. I just don't care for the accessory mount system that comes with the short water pump so I always convert my big block rigs to the long water pump setup.

[68 TT]

Originally Posted by 68_chop_top

In talking with a friend of mine who has had more 67-72 trucks and swapped any and everything into them, he told me to put the motor mounts in the front holes and to move the b/h crossmember forward to their holes. That is the way the factory did it. Went out today and pulled the short block out and looked at the crossmember. Sure enough there are pre-drilled holes to move the crossmember forward.
Why didn't I read about this before hand.
Oh well, minor set back.
They say experience comes from mistakes.
I am wiser tonight!

I tried that in my 67 and the big block long water pump 2-groove crank pulley hit the forward crossmember with the motor mount stands in the forward holes. I ended up notching the crossmember for clearance rather than moving the engine back and shortening my driveshaft.

That is probably why they used the short water pump setups in the trucks. I just don't care for the accessory mount system that comes with the short water pump so I always convert my big block rigs to the long water pump setup. Better, more stable design that is less prone to tossing belts at high RPM.

[68 TT]

Originally Posted by 68_chop_top

I will still have to remove the bell housing cross member because of clearance issues. Moving the motor forward will mean the tranny will have that b/h cross member by it.
So should I totally remove the b/h cross member or move it forward to match the amount I move the engine forward. Looks to be about 4 inches. Are there holes in the frame for the b/h cross member?
What did the factory big block and manual transmission set up have?

I don't think the bellhousing mount crossmember can move forward any without mods to it. It is right at the transition area where the frame moves up over the front suspension. I would just remove it and switch to a tailshaft mounted crossmember instead.

[68 TT]

Originally Posted by 68 C10 402

68_chop_top, can you tell me if you got this set-up to work? I have a 68 that was originally a straight 6 and I am trying to install a 402. I got a set of the original frame front mounts but having a hard time with the b/h mount. The original one in the truck was too far back and due to the design could not be moved up as you suggested. I then found a 72 with a small block and manual and grabbed the b/h cross member out of that. This allowed me to bolt everything up but the angle of the engine is way off – tilting the tailstock of the transmission down. If I try to level off the drive train I have about 1.5” gap between the b/h and the x-member mounts. I have been told that there is actually a 68-71 manual transmission x-member specific to the BB but not sure if that is my gap. I am debating going to auto x-member and ditching the b/h version. Wondering if you had any success or if anyone call help me out. Been reading the site for a few years so hoping the answer is out there. I added a few pics for clarity.

Firewall clearance is going to be your issue with those valve covers. Mine are about as tall as yours and I had to shift the engine a little bit forward of the front mount holes on the frame to make the valve covers removable with the engine in the truck. You might want to set the cab in place and check your clearances before locking things down & building a driveshaft to fit.

With shorter valve covers and stock style rocker arms it can go further back and still allow the valve covers to come off. My taller roller rockers with poly locks make me have to lift the valve covers pretty much straight up to get them off. The sides of the firewall recess get in the way.

[jocko]

Originally Posted by 68_chop_top

I will still have to remove the bell housing cross member because of clearance issues. Moving the motor forward will mean the tranny will have that b/h cross member by it.
So should I totally remove the b/h cross member or move it forward to match the amount I move the engine forward. Looks to be about 4 inches. Are there holes in the frame for the b/h cross member?
What did the factory big block and manual transmission set up have?

If you have a rear trans crossmember, you should not attach to the bell housing mount location. It's either engine + bell mounts (or) engine + rear trans mount, but never all 3. So in your case, if you've made a rear trans crossmember, you should not attach the bell to the bell mounts (and you can remove them if there is a clearance issue and not worry about it).

[68_chop_top]

Well I have finally got everything nailed down. I removed the b/h cross-member and used a tranny cross-member like BossHogg69 said. Trying to move the b/h cm forward was all wrong. Probably need the correct b/h cm for a BB. I am not sure they made BB with manual tranny.
I also did not move the motor mounts to the forward most holes as my long water pump and belt assesory would hit the rad. Moved it to a happy medium where the fan fits and able to get the tall valve covers off.
Solution: remove the b/h cm, use shop fabricated tranny cm, move whole engine assembly forward but not to factory holes, have a new drive shaft made (+2.5")

[Tom Vogel]

Originally Posted by 68_chop_top

Well I have finally got everything nailed down. I removed the b/h cross-member and used a tranny cross-member like BossHogg69 said. Trying to move the b/h cm forward was all wrong. Probably need the correct b/h cm for a BB. I am not sure they made BB with manual tranny.
I also did not move the motor mounts to the forward most holes as my long water pump and belt assesory would hit the rad. Moved it to a happy medium where the fan fits and able to get the tall valve covers off.
Solution: remove the b/h cm, use shop fabricated tranny cm, move whole engine assembly forward but not to factory holes, have a new drive shaft made (+2.5")

Thats the right way to do it.^

[68 C10 402]

Thanks for the advice. Does anyone happen to have a BB manual B/H x-member laying around that they are willing to part with? Hey, I have to at least ask… If not, how about an automatic x-member for a 68 2wd? I was really hoping to run the B/H style but want to keep the project moving along.

Thanks again to all who responded.