SBC-700R4 in 71-drill cross member?

[Steve Van Gent]

Guys,

Just dropped in 350 and 700R4 in sons 71 truck (origional 250-6 and 3 speed manual). Used mounts and cross from doner long bed truck 72 over to his short step side (it had stock 350/th350 eng/trans). I have moved the power steering box, column, shift links, etc from doner truck. The engine perches are in the forward set of holes, we were very careful to copy the stock install from the 72 doner truck. Now we are trying to bolt up the cross member and holes do not line up...

Here are a few questions;

1. Is the 700R4 longer to tail than the th350? Is it normal to have to re-drill holes for cross-member? Do I need all 8 bolts, or just 4 lower OK?
2. We used chop saw to remove the bell housing cross member from frame, kind of ugly, but rivits dont seem to want to come out-appears hot-rivits. Is there a better way to remove?
3. lengthing drive shaft to exactly 59"...does this length seem correct for application? Typically lengthen?
4. COlumn shift appears to be correct and dry-shifts fine. DOesn't this mean length is correct?
5. Any other 'gotcha's' I should watch for?

Thanks,

Steve

[stomper]

Steve,

I am also doing the 700r swap in my '71 SWB. It's a couple inches longer to the mount so not unusual to drill holes for the trans cross member. I am using an ECE cross member and I still had to drill for that one. I would put the 4 bolts in the top too. Others may chime in with having been OK with just the bottom but I'd feel safer with all of them.

Rivets!? UGH I did almost 50 in my frame. Grind off the head, pound it out with a flat punch. ...if necessary.

I read that one piece drive shafts for short trucks and a 700 R should be 56". Measured center of u-joint to center of u-joint. I had one laying around that is 55" or so. I will lengthen it later.

Shifter linkage, just make the geometry work. If you can select all the gears you're good.

You didn't mention the converter lockup switching or TV cable hookup. those are your two biggest challenges and you must do them correctly. There are a few ways to do it depending what trans you have. Search the board and you will find lots of info.

[MARKDTN]

Every application is a bit different. I would not cut a driveshaft without having everything installed and measuring. Different rearends move the pinion slightly for example.

[Steve Van Gent]

Originally Posted by stomper

You didn't mention the converter lockup switching or TV cable hookup. those are your two biggest challenges and you must do them correctly. There are a few ways to do it depending what trans you have. Search the board and you will find lots of info.

For TV, I have a recipie for Edelbrock carb/Edelbrock manifold that works great with aftermarket bracket. Adjuster works good. Usually take to my tranny shop, let them do final-usally they dont charge me.

As for converter lockup, I have stock coverter from Trans-am. I was not aware this would not work...I am not racing this, only street show and daily driver. What is the issue we are fixing?

Thanks,

Steve

[Steve Van Gent]

oops! I re-read post, I think you are talking about 4th gear torque convert lockup with brake pedel switch cutoff...Yes, I am familiar with this wiring exercise. However, should be noted that one does not actually have to do this hookup according to tranny shop, only helps with fuel milage-or so they claim.

[Katrina/10]

Originally Posted by Steve Van Gent

Guys,

Just dropped in 350 and 700R4 in sons 71 truck (origional 250-6 and 3 speed manual). Used mounts and cross from doner long bed truck 72 over to his short step side (it had stock 350/th350 eng/trans). I have moved the power steering box, column, shift links, etc from doner truck. The engine perches are in the forward set of holes, we were very careful to copy the stock install from the 72 doner truck. Now we are trying to bolt up the cross member and holes do not line up...

Here are a few questions;

1. Is the 700R4 longer to tail than the th350? Is it normal to have to re-drill holes for cross-member? Do I need all 8 bolts, or just 4 lower OK?
2. We used chop saw to remove the bell housing cross member from frame, kind of ugly, but rivits dont seem to want to come out-appears hot-rivits. Is there a better way to remove?
3. lengthing drive shaft to exactly 59"...does this length seem correct for application? Typically lengthen?
4. COlumn shift appears to be correct and dry-shifts fine. DOesn't this mean length is correct?
5. Any other 'gotcha's' I should watch for?

Thanks,

Steve

The 700 is about 2 inches longer. I removed the rivets from the top brackets of my trans crossmember and did not use them.

A driveshaft from a 6 cylinder truck is the correct length when used with a V8 in the forward mount position and a 700R4.