Questions on 4.8 in a '70 GMC

[2kwik4u]

OK so heres my dilema. I am going to have 2 trucks here soon. my '00 S10 Xtreme and a '70 GMC (reg cab short/stepside bed). The S10 has a 5.3/4L60/AWD swap planned so I am going to have to make the '70 driveable for a few months. As it sits right now the '70 has no motor. I got to scouring ebay and found a few 5.3's and 4.8's for around $1000-1200 or so. But I have arrived a few small questions.....

1. Am I going to need anything other than the motor/harness/ECM/accessories? I have read quite a bit lately, and want to make sure that the ECM will work without some of the other modules plugged in (BCM/Cluster/cruise/Tranny). I am thinking that the ECM will simply "think" that it is a bare bones truck with nothing else to "talk" to.

2. Has the LS1 platform changed the tranny bolt pattern at all? The truck currently has a TH350 in it which I would like to change out for a 700R4 I have sitting around (after a quick rebuild). Am I going to be facing any MAJOR problems with his combo? Or should I sell the TH350 and the 700R4 and get a 4L60E and let it work with the stock ECM?? Money is not a big deal, but I don't want to buy another tranny if I don't have to.

3. Does anyone else see any problems that I have perhaps skipped over/missed?? The mounts are not a problem as I have acces to both a welder and a cutting torch, so I can make those work...same deal with the crossmember.

Thanks in advance.

Mike D

[incoma]

I'm working with the same conversion right now. The LS1 will work just fine in the 70 truck. From what I've read, so long as the tranny has a speed sensor in it, you'll be ok (your idle will work correctly).

Guys with the vette/z28 LS1 have had to notch their frames to fit the LS1 in. I "test" mounted my truck 5.3L in the frame last night and didn't see any problem aside from the power steering hoses hitting the frame. I'm going to be doing some more work with that this weekend so I can get my frame back to the powder coater. I haven't gotten my 4L60E from the tranny guy yet. I'm having him build a pre-97 4L60E that will have a pre-93? tail shaft and housing so I will have the proper mechanical spedo drive. He's also going to mount the reluctor ring for my speed sensor.

Just curious how you intend on handling the gear select linkage, throttle cable, and fuel delivery? I haven't decided how to do this quite yet, particularly if I mount the engine back to accomodate the frame clearance. I dont' want to cut the frame if at all possible. That's not an area that I want to weaken.

[2kwik4u]

Fuel delivery.....

At this point I am thinking I will hit hte juknyard and find myself a gas tank from a somewhat modern FI truck and make up some custom mounts for that, as well as replace the fuel pump.

Throttle cable I'm not 100% sure of yet, however I am sure I'll figure something out

Gera selection will be something along the lines of a cable shifter of some sort.....Haven't gotten that far right yet.....It's in teh back of my mind though, I am thinking perhaps a newer cable from a fullsize might work as the length will be similar.

I'll keep everyon updated as to the progress

[incoma]

If you position the engine correctly in the engine compartment, you should be able to use the stock gear selection. At least that's my plan at this point.

[GMCwantsLS1]

On mine I swaped the hardware from the old transmission to the new one. This allowed me to use the stock column shifter on the new transmission.

[2kwik4u]

Sweeet,

Thanks for the info guys.....Looks like I'm going to ahve to hit a junkyard though......totally forgot that the previous owner has some kinda B&M gated shifter thing on there......Never paid attention to the fact that the stock column shifter is MISSING...Oh well just another itme on a lost eh??