LS1 in bagged/bodydropped obs truck?

[ryan350]

Hi all well this is my first post as i have just stumbled on this site! great site too! I have a 1990 model c1500 pick up that is in the process of being bagged and bodydropped. I was thinking about running a early 90's corvette TPI engine in the truck but am now leaning towards a gen3 (LS1) as there easier to get and cheaper ( I live in Australia). I have a few questions regarding the install of the engine.

1) I have heard that in a obs truck the frame (chassis) has to be notched for the air compressor to stay in it's stock location on the ls1 as the compressor hits the frame,true or false?

2) Can the stock radiator out of a obs be used with the LS1 engine? if not which radiator is used?

3) In matter of ease of the conversion can the stock LS1 wiring loom be used for the conversion or is it easier to use one from nelson performance? I gather the ones from nelson performance plug straight into the factory computer making it more a plug in and go conversion?

I think that's all for now! also my truck in stock for was a 5.7/auto trans combo

Thanks in advance ryan

[ryan350]

also one more question! I will still be running and automatic transmission, now just wondering if i still you the stock transmission crossmember? thanks

[5.3swapn1992]

HELLO THERE ITS NOT GOING TO BE THE EASIEST SWAP YOU WILL EVER ENCOUNTE I HAVE JUST PUT A 2001 5.3IN MY 1992 CHEVY EXTENDED CAB YOU CAN RUN THE 700R4 AUTOMATIC WITH THE HUGHES FLEXPLATE AND ADAPTER ALSO YOU WILL NEED THE THROTTLE VALVE CABLE FOR TRANNY ALSO I HAD 1992 TUNEDPORTINJECTION ON MY 383 AND IT CANT COMPARE TO THE FACTORY LS POWER.FR THE A/C THERES A GUY ON HERE [SUPERPOWERS] THAT MAKES A BRACKET FOR YOUR FACTORY A/C I HAVE ONE AND IT WORKS GREAT. BUT YES THE FRAME WILL NEED TO BE NOTCHED TO ANSWER CORRECTLY THE NEW ENGINE WILL NOT MAKE ANY COMMUNICATION WITH THE OLD PCM YO WILL HAVE TO RUN TwoCOMPUTERS AND THE OLD ONE WILL MAKE YOUR SPEEDOMETER WOrk also you will need the relay for 4thgear lockup , the stock radiator can work if you buy the flexible radiator hoses thats how i have mine i know i have left alot out but any more questions i can help you with just ask

[ryan350]

dam well that sux then! how much of the frame has to be notched out? does anyone have pictures at all? Is it only because of the ac comp that the frame has to be notched? also could i use my transmission that i already have?

[ChevyLee]

Hey, so if i was you i would not run the ac down there. I ran mine and just had problems, and if you want your motor to sit back which will look better then you will run a compressor on the top or side. My lines would crack from the motor moving and the newer style ac would freeze up the condensor so the ac would not stay cold for long.

[flattopwill]

Wow. Some forum members need to remember to use punctuation and sentence structure.

Just to clarify:
1. To mount the compressor in it's original location the trucks frame will have to be notched. OR you can buy a bracket kit that will mount it (or the truck's original compressor) up high away from the frame. A couple people that sell this kit are Powers, Kwik Performance, and Street and Performance.

2. The truck's stock radiator can be used just fine or you can use a radiator from the newer trucks but you have to mount the overflow bottle that's part of it's system.

3. The original harness can be used after it is modified to run as a standalone powertrain harness. You can send your harness to a company like Nelson or Speartech to be modified or you can buy one of their custom harnesses. One of their harnesses will be closer to plug and play but not completely. You will still have to make some connections.

Alright now that I've given you tips it's time to give me tips on how to bag my truck. Lol just kiddin but that is next for my truck.

[ryan350]

thank you flattopwill for the info!!! From the way you have explained it, correct me if i'm wrong but if i was to use the standard a/c compressor of my tbi engine and purchased the new mounting bracket, i would not have to notch my frame correct? If this is correct i am deffinantly running the ls1 engine!!! also here is a link to my build thread if you guys want to see my build progress, also it may interest you guys that it's RHD! cheers ryan
http://www.fullsizechevy.com/showthr...500-bag-and-bd)

[flattopwill]

Yes you are correct.

[ryan350]

once again thank you very much flattopwill!

[ryan350]

also could someone post a link to the engine mount adaptors please? thanks again ryan