K20 Engine Moved Forward??

[72longbed]

Posted this question on the 4x4 Board and got mixed results so I'll give it a try here.

I'd like to know about moving my small block engine forward in my 72 K20/4 speed/ NP205. The engine is stock with points distributor right now but I intend to pull that one and put my HT 383 with the HEI in it's place. I intend to use a 700R4 and the NP205. I know GM didn't do it that way 35 years ago, but since when has that stopped US!! In the last three years I am sure I have read many other Posts about engine location and would like to hear from those members that have done this type of move.

What are the "Pro's and Con's", and how far forward is far enough? Are there things to watch out for such as steering box/header clearance, front diff/ oil pan, etc., etc.,..... Maybe their is a rule of thumb on how far to go before you get into trouble with clearances.

Again, just looking for input from those that have tackled this before and learned from the experience, and would like to share with me.

Thank you for your help,
72longbed

[GM72K10]

Both my 72 smallblock 4wds have the engines in the "original" location and both have HEI distributors with no problems, as for my big block 4wd . . .

[71swb4x4]

I plan to put a 700r4 in my 4x4 as well. If I remember right the 700r4 is 1 3/4" longer. I plan to move the engine forward as opposed to moving the transfer case back. I think the 2wd V8 position is 2 inches forward of the 4x4 position, so 1 3/4" shouldn't be too much of a problem. I am sure things will pop up but here is my list so far:
Radiator hoses shortened
2wd fan shroud
lengthen throttle cable
lengthen fuel line
move engine crossmember
This is what I have on paper. Obviously when I get elbow deep into I will find a few more challenges. It wouldn't be fun if it was any other way.

[67ChevyRedneck]

Does your truck have a V-8 now?? My 67 had an I6 and I bought some factory V-8 mounts and moved them to where they would have been mounted in a V-8 truck. I have about 2" of clearance from my flex fan to the radiator and about 2 inches from my HEI distributor to the firewall. If you already have a v-8 in the truck in the stock v-8 location I personally wouldn't move it anymore forward. I have heard that you can change the tailshaft of a 700R4 to that of a th350 or th400. Maybe you could post that on the engine and drivetrain board to see if anyone has done that. I know a 700R4 tailshaft is longer than the other automatics. I put a 700R4 in my truck and I had to move the crossmember back about 2 inches? or so. I also had to shorten the driveshaft. I would be a real pain to move the transfer case... I have a 69 4x4 I would like to put an overdrive in someday, let us know what you find out!

[67ChevyRedneck]

crap, how did i miss the V-8 thing? Not sure about the 2wd vs 4wd engine location, I thought there was only an I6 and a V8 location. Maybe someone who knows for sure can answer....anyone??

[mrein3]

The attached photo is my newly completed 383 project. You can't really tell from the photo but that is a GM HEI distributor there. The engine is in the stock 4x4 location.

WHEN I install the 700r4 I have I will be moving the transmission/t-case crossmember back verses moving the engine forward.

Some things to think about:
Going from a stick to a auto creates some problems with the t-case adapter. If you are going from a th350 to a 700r4 with a NP205 all you need is the Advanced Adapters (AA) output shaft in your transmission. It is the correct length and spline count to fit your th350 to np205 adapter. AA has a part listed in their catalog for using a 700r4 in place of a 4-speed manual but I never researched that.
The t-case behind a manual transmission has a 10 spline input shaft. The t-case that came from the factory behind a th350 has 28. When I went from my 3-speed manual to my th350 I purchased a complete th350, adapter, and t-case from a donor.

Going through all the screwing around you have to do for this swap it just seems easier to me to move the t-case back verses moving the engine forward. To move the t-case back all you need is to get different driveshafts made. To move the engine forward you need to worry about your fan shroud, clearance with steering, oil pan, etc.

The "how-to" article I read on-line a few years ago moved the t-case back. Maybe that is why I'm biased that way.

If you move your engine forward, please take photos and post them. Maybe I'll do that instead.

[64fleetside]

I think the engine is set back to clear the front pumpkin, not sure if it will clear oil pan w/o a signifcant lift. GM musta had a reason. Brian

[rjstj]

Mines going forward. With the Advance adapters shaft installed and a 2wd fan shroud it should be fine. This will keep the drive shafts, transfer case, transmount and shifter in the same location. With 8 inches of lift I'm not worried about hitting the oil pan on the front diff. I can't see any more problems caused by moving the engine forward 1 3/4" than putting a winch and winch bumper on the front. It still won't be as nose heavy as a big block stuffed in there, which GM didn't do either. The only other thing I noticed where the headers may interfere with the front shackles but that won't be that big of deal either.

Randy

[72longbed]

Wait a minute here, if what mrein3 is saying is true, then I won't be able to use the stock manual tranny transfer case with my 700R4, right??? I hope this is not the case, but if anybody can verify this info please do. Good thing I raised the question about moving the engine, this is exactly the type of "colateral" info that I need.

I'm not prepared to tear down either my new Bowtie Overdrives 700R4 (will void any warrantee), or disassemble a perfectly good working NP205 to change out the shafts, so if anybody knows of an easy way to mate the stock 10 spline transfer case to a 700R4, please chime in here. Rather know if it can be done easily before I get into it and have to put it all back together stock.

Thanks for all the input,
72longbed

[mrein3]

Originally Posted by 72longbed

Wait a minute here, if what mrein3 is saying is true, then I won't be able to use the stock manual tranny transfer case with my 700R4, right??? I hope this is not the case, but if anybody can verify this info please do. Good thing I raised the question about moving the engine, this is exactly the type of "colateral" info that I need.

I'm not prepared to tear down either my new Bowtie Overdrives 700R4 (will void any warrantee), or disassemble a perfectly good working NP205 to change out the shafts, so if anybody knows of an easy way to mate the stock 10 spline transfer case to a 700R4, please chime in here. Rather know if it can be done easily before I get into it and have to put it all back together stock.

IF you had bowtie overdrives build the 700r4 to replace A 4-speed in front of a NP205 you MIGHT be good to go.
If you have a 700r4 with a tail shaft on it you probably DO NOT have the correct setup. The 4wd version of the th350 and the 700r4 have no tailshaft on the back of the tranny. I seriously doubt the part listed in the advanced adapters catalog for this application still uses the tail shaft on the back of the 700r4 tranny.
A simple check would be to count the splines on the output shaft of your transmission. If it has 10 it MIGHT have been built for what you are trying to do.
I have never delt with them but I understand bowtie overdrives is a great company to work with. I would contact them and ask them what you have and if it will work.

As far as moving 1 and 3/4 inches forward that measurement is for when you are replacing the th350 with a 700r4. The adapter (the part between the transmission and the transfer case) is MUCH longer on the manuals than it is on the automatics. Because of this, IF THERE IS A 10-spline OUTPUT SHAFT IN YOUR 700r4, you'll be moving much farther forward than if you are replacing a th350.

GM made all the driveshafts the same length for all NP205 4wd trucks made from 67-72. The difference in length was made up in the adapter. The shorter standard transmissions had longer adapters. The longer automatics had shorter adapters. I know for a fact that the th350, adapter, and NP205 out of a 1972 Blazer is the exact same length as the 3-speed on-the-tree manual, adapter, and NP205 out of a 1971 long wheel base pickup because I personally did the swap and used the same driveshafts. In fact the adapter bolted to the same crossmember in the same place on the frame.

All that changes when you go to something not stock. Like a 700r4.

Don't forget when doing your swap that you need the linkage for an automatic. I understand the stock th350 linkage works with the 700r4 - again in the factory position. When you move the whole works farther forward all bets are off.

[Vince M]

No matter which way you go (moving the motor forward or moving the T-case back) either method has compromises. By moving the T-case back helps with the front drive shaft angle. It is really short in the original location, and if it's a long bed you have the move will shorten the rear driveshaft.
I looked into this swap when I had my 4x4 but it had a TH350 already. Since this is a manual conversion it will increase the amout of work. Are you planning on a floor shift or column mount for the 700R4? Do you have the TH350 adapter for the T-case? These adapters are hard to find used and are still available new (apx $300 bare).
Whichever way you go plaese post your results.

[breeh]

I moved my motor forward approximately 2" when I swapped to a big block with a 700r4/NP205. The bonus in this was that my front driveshaft did not need to be reworked and the T/C shifter comes up in the factory location in the floorboard. Also, as stated earlier, I used a 2wd big block fan shroud and it fits just like the General put it there.