thinkin bout a motor swap..

[TJ79Cheyenne]

K so i have 2 squares. Ones a 79 with a mildly built 350 the others a 350 tbi with a 700r4 trams. Lately ive been having issues with both trucks. The 79 has a wiring issue so the ignition likes to go from working perfect to not working at all. My tbi has a bearing knock and i dont feel like blowin it up... So ive been thinkin of pullin the motor out of my 79 n putting it in my 87... What do i need to know bout doing this swap? What do i need? What can i get rid of? How do i make it run right? I just need some tips on doing this since ive never tried this before

 

[72chevy2door]

You will need the heads and intake off the tbi motor. And the camshaft because tbi motors have a specific camshaft grinds. I'm going through a lot of problems with my tbi system right now but that's cause I have a rv cam in my truck but don't be discouraged on the tbi. The heads and intake are a guarantee because the center bolt valve cover heads have the center two intake bolts at a different angle than the pre 87 heads. You can use the carb intake on the tbi heads as long as you oval out the center two holes on both sides.

 

[Thunder]

Have you pulled the pan on the knocking motor? You might get away with rolling a new set of bearings in and getting another 50,000 out of the motor. I have done a few of them myself and had good success. It will give you the time to track down a good builder motor and rebuild it the way you want it. Then make the swap, less downtime and better results.

 

[Jims86]

an engine would be better than a motor, unless you have access to a wrecked Tesla.

 

[TJ79Cheyenne]

Haha im talkin about pulling the carbd motor out of my 79 n putting it in my 87 that has the tbi 350 in it right now. Not just swapping the carb in

 

[Thunder]

You'll still need an "Engine" for the other truck. Just trying to save you some headaches. i'll go back to being an Idiot.

 

[72chevy2door]

In order to put the 79 engine in your 87 you must use the cylinder heads, intake, throttle body, valve overs, camshaft, and distributor etc. etc. out of the 87 truck. Your best bet would be to fix whatever ignition issues your having with the 79 and then doing what thunder said and rolling in a new set of rod bearings. Or just rebuild the 87 engine.

 

[72chevy2door]

@Tj79 what kind of ignition problems are you having? Does it run good then when it warms up it won't start again? Is it HEI or points? Maybe we could help you figure out what's wrong with your 79 so you have a reliable truck while the 87 is down

 

[Driver4r]

I discord about the heads, he can make the intake work with slight modifactions.

 

[TJ79Cheyenne]

Ok ill give ya the rundown on my 79 ignition problem. I just replaced the ignition switch for the second time and everything worked fine until yesterday when i stopped for gas. Doesnt seem to matter if the trucks warm or not, its done this once before and i replaced the switch and adjusted it right. But anyways, i turn the key and my dash components come on, voltmeter, oil pressure, etc.. turn the key to start and it kills power to everything like its supposed to but it wont crank at all. Before id let it sit for a couple days and it works again, not this time. Im gonna try replacin the starter (again)... The fusible links near the starter are already cut out and wired back together. It is a hei distributor

 

[TJ79Cheyenne]

So you guys are sayin i cant just drop the 79s motor in and figure out dist. Wiring from there?

 

[Driver4r]

The intake is different cause of the throttle body, but i guess if the 79 is a 4barrel, then you could buy an adapater plate to bolt the TBI on.

 

[Irishman999]

I call ******** on all you guys.

Original poster give me your address, I have a carb to TBI manifold adapter plate I ordered for my big block that I cant use. I will ship it to you for free, basically lets you put a TBI in place of a carb, all you would need is the gaskets.

I can relate here, Aftermarket does not offer anything good for a TBI big block. I ended up buying a carb intake and making the rest work. The only actual modification I had to make was drilling and tapping a hole for my coolant temp sensor. The rest of the TBI stuff was just kinda retrofitted on the engine.

 

[72chevy2door]

@Irishman what about egr? @Driver yes he may be able to use the 79 heads if he modifies the tbi intake, I agree with that 100%. If he does do the intake swap using the 4barrel intake with a tbi he might run into the problem of it not having enough manifold pressures to allow the tbi to work correctly. I did a lot of research on that before and I learned to not mix stuff on tbi units. @tj my fathers suburban used to do the same thing. Found out the HEI coil was bad. It did fine on ohm testing and stuff but when it got hot from driving it it would kill the engine and wouldn't start again until it got cold. But your saying it's not turning over.... That could be your battery is loosing it's cranking amps I've had a red top optima do that just recently. Don't just replace the starter that will get expensive. Have a local parts store test it. Autozone and oriellys does it free where I live. Once you do take the starter off make sure the surface where the starter touches the block is clean of paint and oils because the starter grounds out there. If not it grounds through the bolts which ain't good enough(learned the hard way). Make sure battery cables are all clean of corrosion and ain't broken or chaffed up. When you do get her running check the alternator just to make sure she is putting out the 14volts like it should.

 

[TJ79Cheyenne]

Yeah advance tests em for free here too thats what i was going to do. The starter is still on warranty thank god. Ill have to do that probably tomorrow or monday... Might pull the switch again and warranty that out as well..