Installing 700R4 in '64 C10 (same for '64-'66)

[Trump]

I am posting this to help anybody that may be doing this conversion. I will also start with saying that there are a million ways to skin a cat. In other words, this worked for me and my truck. I'm sure others have done it differently and have other methods. Feel free to post them if you like.

I am doing this conversion using the stock front engine mount brackets (relocated) and the POL transmission cross-member. (http://www.performanceonline.com/196...N-CROSSMEMBER/)

I will get some comments out of the way upfront. In my opinion the only way to use the POL cross-member and retain the factory emergency brake is to use a Caprice style tailshaft housing on the 700R4. It allows for a trans-mount further back on the trans. If you use the mount that is cast into the case, the trans x-member will be trying to occupy the same space as the brake cross-member/support. Also, the x-member is not bolt in if you go my route. You must re-drill all new holes.

I had to move the engine forward to make this work. The reason is that because I was using the stock front mounts and the fact that the 700R4 has a larger case, I could not get the trans to fit right without interfering with the body flange that joins the firewall to the floor. I also didn't want to hillbilly it up by bashing it all with a hammer to get clearance.

Also, my truck was originally a I6 w/ 3spd manual. The previous owner torch-cut out the mid mount X-member. It was ugly but I intend to clean it up later. Your middle x-member will need to be removed as well. The POL x-member will be strong enough to restore chassis strength once installed.

So to start, I unbolted the stock front mounts. I moved them to the next set of holes forward of their stock location on the top rails of the chassis. I used 1/2" nuts under them to act as spacers because the frame pinches in that area and lifting them up puts them farther apart and almost exactly the same distance apart as the rear holes. You should have about 15.5" between the mount holes when relocated if using the stock rubber mounts. I did not tighten them down all the way so that I could position them when drilling for the lower holes on the mount brackets. I did this by getting the brackets where I wanted them and then drilled elongated slots in the front X-member like the factory did.

I then removed the stock emergency brake support to get it out of my way.







I then bolted up the mount brackets to the front mount. I left all the bolts only attached and not tightened so that I could get everything where I wanted it first before tightening them down.

I then dropped the engine and trans in as one unit. I used an engine leveler and a hydraulic jack at the trans tailshaft to guide it to where I wanted it. With the mounts loose and the engine still on the crane, I installed the motor mount bolts to join the engine to the mount brackets. I only hand tightened those for the same reason as above.

For the next step to work, there is an exhaust hanger that is riveted to the inside of the chassis on the driver's side about at the rear door of the cab. That has to be removed because the POL x-member ends up there. I used a grinder and air-hammer to get the job done. You can see it in this picture:


I then went to the rear and centered the trans and got the POL x-member where I wanted it. It ended up being about 12.5" forward of the rear x-member (where the trailing arms mount) to the rear of the rectangular tubing of the x-member. I then pulled horizontal and diagonal measurements to make sure everything was square and then used Vise-grips to clamp the x-member in the chassis for drilling. Once drilled, I lower the trans onto the X-member and put the bolts in loosely.

Once everything was where I wanted it, I went back and tightened down all the bolts.

The end product moves the engine about 3" forward, conveniently that is almost the same length that the 700R4 is longer than the Powerglide and TH-350. So you most likely can use the driveshaft you had before for this. The added space gives a lot more room between the engine and firewall so if you desire you can run a HEI distributor without any problem and have room to spare.



I admit, I would prefer if the engine was closer to the firewall because I never run HEIs and I think the lack of the gap looks a bit better, but for this combo and my methods, it was required. Keep in mind you will likely need a shorter fan spacer once it is all said and done.

So that is how I did it. Like I said before, I know others have done it differently. This was just my method. I hope that it helps somebody.

If you need better pictures or other pictures of the end product, let me know and I will try to help.

If you don't like the distance between the firewall, You could could likely keep the engine spacing by modifying the front mounting brackets to make them shorter and using a dropped trans x-member, but you would not be able to retain the factory emergency brake. You might also run into interference issues with your driveshaft and rear x-member. In this case you would also have to use a shorter driveshaft due to the added length of the 700R4. 1990's 2wd S-10 driveshafts will work with the rear U-joint changed. Just another way to do it.

[gmcdeadhead]

does anyone no if you have to move the I6 motor forward if your doing the 700r4 swap in a 66.?

[pdxhall]

Good write up Trump. I just finished my 350/700r4 installation and went a very similar route. I used the CPP trans mount and CPP tubular engine mounts that mount in the forward holes and have the passenger style mounts. I picked up a 1999 Silverado driveshaft set up that I am having shortened, balanced, and new u-joints installed. I think the engine looks more balanced in the engine bay in this location. Here's the only pic I have of mine right now.

[bj383ss]

Interesting write up. Makes me wonder about mine. I am pretty sure it has the original driveshaft and it is original length. My engine is in the factory location and the previous owner used the brake crossmember to mount the 700R4. Cutout a slot in the x member so the trans would fit. I haven't looked close but I don't think the floor was messed with. I know the HEI was real close and I couldn't even reach one of the rear screws to loosen it.

So if I move it forward like you did will I still be able to run a mechanical fan? Mine has a long water pump and a flex fan with a 3" spacer.

Bret

[Trump]

Originally Posted by bj383ss

Interesting write up. Makes me wonder about mine. I am pretty sure it has the original driveshaft and it is original length. My engine is in the factory location and the previous owner used the brake crossmember to mount the 700R4. Cutout a slot in the x member so the trans would fit. I haven't looked close but I don't think the floor was messed with. I know the HEI was real close and I couldn't even reach one of the rear screws to loosen it.

So if I move it forward like you did will I still be able to run a mechanical fan? Mine has a long water pump and a flex fan with a 3" spacer.

Bret

Yes, I think you should be able to, depending on the rest of your cooling setup. There is plenty of room still in front of the engine. I intend to keep my mechanical fan (not stock) and use a stock fan shroud. Once I put it all together, I will post more pictures. I am waiting on a couple parts to arrive still.

On the HEI- that is pretty amazing that you could get one in there. I couldn't even remove my stock style distributor without taking off the cap and rotor to get enough clearance to lift it out. On mine there would have been no way of using an HEI, unless it was the external coil style.

[Trump]

I should probably mention for those interested that I am using a Gennie Shifter on the floor called a "Lo-stick- mid-mount" (http://www.gennieshifter.com/shifter-lostik.php). It will allow me to change out sticks and knobs on the fly and has a lot of adjustability for final location once mounted. The hole for the shifter ended up right behind the firewall to floor body flange. Which I like since it will push the shifter forward a bit. My last shifter (unknown but believed to be Mr. Gasket style) sat further left and rear and was always in the space my knee/thigh was trying to occupy. The knob would also be up against the seat when in drive. So I'm glad I will be able to better position the shifter.

[Trump]

Originally Posted by gmcdeadhead

does anyone no if you have to move the I6 motor forward if your doing the 700r4 swap in a 66.?

I don't know for sure, but would assume it would be the same case since they used the same mount locations and setup for everything except the radiator. If you ended up doing that with an I6, I would also assume you would have to convert to the V8 radiator location to move the rad further forward. This has its own repercussions and may require some additional ingenuity.

[gmcdeadhead]

i talked to captain fab, he said you should not have to move the motor foward, thats why i would need to cut off 3" off the drive shaft. i figured thats what has to be done.

[Trump]

I would think that would work as well. I don't know for sure, but would think there would still be some issues with the parking brake support.

The entire reason I moved everything forward was the interference issue with the firewall to floor body flange against the transmission case. Unless the I6 engine sits lower at the bellhousing than a V8. I would imagine that the interference will remain. But Like I said, you could also overcome that by bashing the flange down. I just did not want to do that.

[gmcdeadhead]

well i'll let you no in the spring time when i start on the 700r4 swap. im gathering all my parts now so i'll have everything to get it done. i have a 66 , so there is no need to modify the e-brake assembly like on the 65 and earlier trucks.

[pdxhall]

Regardless if you move the engine forward or not you will sill need to have the driveline shortened, just not as much if that matters.

[dougf]

Thanks for the article and pics! Good job.

[kieth]

Originally Posted by gmcdeadhead

well i'll let you no in the spring time when i start on the 700r4 swap. im gathering all my parts now so i'll have everything to get it done. i have a 66 , so there is no need to modify the e-brake assembly like on the 65 and earlier trucks.

We used later style motor mounts 91 burban in a 66 gmc, moved to the forward hole in the frame, ended up shortening the driveline 1.5"........no problems with a tbi 350 and a 700r4.........used a cpp transmission crossmember......it was a easy install with no interference from the valve covers or the distributor. Kieth

http://kieth.smugmug.com/Trucks/66-GMC/i-XnWz9nk

[ljackson]

Thanks for the post Trump and others.

[ctough74]

I know this one is old, but a great write up. I am also moving the engine forward however have used the stock trans x-member. I am now at the point of looking at coolant hoses. Having the engine moved forward, the bottom heater hose is kinked a bit and the upper 'pipe' (stock) doesn't really fit that well.
What did you use?

[twoskies]

good write up as said, hey pdxhall

im going to use pretty much the same setup you have in an old post, think its year dated 2014, lol

5.7 vortec, carb intake and manifold
700r4 transmission

question is aside from the cpp mounts and moving the motor to the forward holes, what other parts did you end up using
transmission support , etc

also if you have a current picture of your truck with this combination

im a parts gatherer before i get everything together, dont like to have to scramble at the last minute, lol

Thanks alot