73-87chevytrucks.com
73-87 Chevy _ GMC Trucks => Engine/Drivetrain => Topic started by: dburbach85 on April 18, 2016, 06:28:20 pm
-
Hi everyone, and thanks in advance for welcoming me to the Chevy truck fold. I recently purchased a 1987 Chevy C10 (well for whatever reason the '87 year is called the R10, but as far as I know there's no difference). I didn't pay much for it and the previous owner had completely restored the body so there's not a spot of rust or a dent on the truck. Unfortunately, though, I recently discovered that the truck's 4.3 V6 is on its way out. I think the rear main bearing is on its way out as the truck starts to struggle to maintain oil pressure after its been running awhile and a knocking sound beings underneath the engine after 20-25 minutes of driving.
Anyway, all that to say, I want to swap in a 350. Any advice on parts I'll need, engines to look for, and on the work of actually doing the swap is greatly appreciated.
I'm hoping to stick with the TBI setup and the truck has the TH400 automatic transmission in it.
-
You will need the TBI top end. Save yourself some hassle and just look for a complete 87~95 TBI engine.
You will definitely need to change your engine mounts to the small block type. Possibly the exhaust, too.
Everything else should be the same. Even the accessory drive, power steering pump, alternator, water pump, A/C compressor, etc. should just swap right over.
-
Yes, see my thread entitled "engine swap diary:" i went the opposite way---from v-8 to v-6, but some of my notes should help:
http://forum.73-87chevytrucks.com/smforum/index.php?topic=29914.0
You have it easy because v-8 parts are so easy to find, v-6 not so much:
1) You'll need new mounts, specifically frame perches which attach to the frame---the v-6 and v-8's DO NOT interchange. But v-8 frame perches are so easy to find--either new, aftermarket or salvage yard. The actual engine mounts between v-8 and v-6 could interchange but let's do it right. With v-6 i think the passenger side is clamshell on the engine and mount on the perch. Whereas driver's side is clamshell on the perch, mount on the engine. With v-8 both sides the clamshell are on the engine and the mounts are on the perches (i think?) Why GM did this, i have no idea?
The holes are probably predrilled on your frame for the v-8 frame perches.
2) The v-6's radiator hoses most likely will not work with the v-8.......or they may be too long and could work if trimmed. The heater hoses should plug right in though. You will most likely need a new, larger radiator eventually. But you probably already knew that.
3) The v-6's throttle cable probably can't work with the v-8 because it's too short, but try it first. If it doesn't work, not big deal as v-8 throttle cables are so easy to find anywhere. v-6? Forget about it----either used or custom build.
4) The v-6 power steering hose and line MIGHT be able to work with the 8. The low pressure return line can be easily shortened if necessary and the hard supply line may be able to be pivoted foward a little.
5) If you're switching to a carb v-8, then i have no idea how you're going to get the pump situation and fuel lines working, but there's always a way......
6) The vacuum booster line for the brakes MIGHT plug right in or might not. NOt a big deal as it is cheap.
7) The exhaust WILL NOT bolt up. Again, no big deal as you have too many choices in v-8 exhaust systems. Complete bolt in kits are probably available for these trucks. v-6? You're on you're own unless you want completely stock, but that has to be welded up too.
Can't remember anything else right now. But in sum, you have it pretty easy because you're going the normal way of v-6 to 8. Going the opposite way is a headache.
-
Forgot to add the fan shroud won't work, and you may need to upgrade the radiator.
-
Forgot to add the fan shroud won't work, and you may need to upgrade the radiator.
Yes, the v-6 shroud is too long and i think anyone going to a v-8 should eventually switch to a larger radiator although temporarily the smaller one could work.
Also, i just re-read the original post and you want to stay with TBI. i think the v-8's injectors are larger which also means you may need a new ECM or chip (?)
-
Thanks for the advice everyone, definitely helpful.
One thing I should have also mentioned, this build will be on a pretty tight budget, so sourcing the engine at the right price is important.
How hard is it to put a TBI setup on a pre-1987 SBC? There's a guy willing to sell me a rebuilt 305 (not as sexy as a 350, but way cheaper) with 0 miles for $500. But the engine is a 1980-85. I already have the TBI intake, throttle body, and injectors off a 350, how hard would it be to make it bolt up?
Also, what troubles would I have with the accessories like the serpentine belt, power steering pump, alternator, etc?
Again, thanks so much for your help!
-
Yes, see my thread entitled "engine swap diary:" i went the opposite way---from v-8 to v-6, but some of my notes should help:
http://forum.73-87chevytrucks.com/smforum/index.php?topic=29914.0
You have it easy because v-8 parts are so easy to find, v-6 not so much:
1) You'll need new mounts, specifically frame perches which attach to the frame---the v-6 and v-8's DO NOT interchange. But v-8 frame perches are so easy to find--either new, aftermarket or salvage yard. The actual engine mounts between v-8 and v-6 could interchange but let's do it right. With v-6 i think the passenger side is clamshell on the engine and mount on the perch. Whereas driver's side is clamshell on the perch, mount on the engine. With v-8 both sides the clamshell are on the engine and the mounts are on the perches (i think?) Why GM did this, i have no idea?
The holes are probably predrilled on your frame for the v-8 frame perches.
2) The v-6's radiator hoses most likely will not work with the v-8.......or they may be too long and could work if trimmed. The heater hoses should plug right in though. You will most likely need a new, larger radiator eventually. But you probably already knew that.
3) The v-6's throttle cable probably can't work with the v-8 because it's too short, but try it first. If it doesn't work, not big deal as v-8 throttle cables are so easy to find anywhere. v-6? Forget about it----either used or custom build.
4) The v-6 power steering hose and line MIGHT be able to work with the 8. The low pressure return line can be easily shortened if necessary and the hard supply line may be able to be pivoted foward a little.
5) If you're switching to a carb v-8, then i have no idea how you're going to get the pump situation and fuel lines working, but there's always a way......
6) The vacuum booster line for the brakes MIGHT plug right in or might not. NOt a big deal as it is cheap.
7) The exhaust WILL NOT bolt up. Again, no big deal as you have too many choices in v-8 exhaust systems. Complete bolt in kits are probably available for these trucks. v-6? You're on you're own unless you want completely stock, but that has to be welded up too.
Can't remember anything else right now. But in sum, you have it pretty easy because you're going the normal way of v-6 to 8. Going the opposite way is a headache.
Thanks for all the info Stewart! Couple questions,
1. why were you wanting to go V8-V6?
2. I'm a little confused on the engine mount vs perch, could you explain the difference? Are they 2 different parts?
-
1) Mainly because i like the engine---also for MPG (although in my case my MPG actually dropped compared 350 and 305. i think this engine is worn out) and also since i mainly use the truck for transportation and occasional weekend type hauling, like going to the hardware store, i felt i didn't need an 8. Also i will say this the v-6 WILL cruise along at 65 or better just as well as a 305 or 350.
Another big reason was space---with this new setup i can actually stand inside the engine compartment---makes it easy to work on the engine.
2) This is an 8 cylinder perch and mount (driver's side):
(http://i223.photobucket.com/albums/dd31/sencraig/000_0460-1_zpshvxmvvod.jpg)
Here is a 6 cyl perch and mount, passenger side:
(http://i223.photobucket.com/albums/dd31/sencraig/000_0404_zps38347d85.jpg)
6cyl driver's side:
(http://i223.photobucket.com/albums/dd31/sencraig/000_0406_zps78f1305c.jpg)
So, basically the perch is a tower/extension to the frame that the mounts bolt to. Some cars use them, some don't. i think the smaller monte carlos and camaros, for example do not use them----the mounts bolt directly to the crossmember in those cases ( i think?).
The v-6 and v-8 perches WILL NOT interchange without serious modification as in using a cutting torch and welding as the 8 has 2 bolts to the top of the frame and 2 bolts to the crossmember, whereas the 6 has 2 bolts to the top of the frame, 1 bolt to the SIDE of the frame and one bolt to the crossmember.
Also, notice that the driver's side v-6 perch has the clamshell bolted to it (instead of usually the mounts bolt to it) and the passenger side v-6 perch has the mount bolted to it. i think the reason why they did this is because the v-6 shakes at idle, but i'm only guessing here. But with v-8, both clamshells bolt to the engine and mounts bolt to the perches.
-
Thanks so much, that cleared that right up. Looks like I need to find some perches!
I really appreciate it!
-
1) Mainly because i like the engine---also for MPG (although in my case my MPG actually dropped compared 350 and 305. i think this engine is worn out) and also since i mainly use the truck for transportation and occasional weekend type hauling, like going to the hardware store, i felt i didn't need an 8. Also i will say this the v-6 WILL cruise along at 65 or better just as well as a 305 or 350.
Another big reason was space---with this new setup i can actually stand inside the engine compartment---makes it easy to work on the engine.
2) This is an 8 cylinder perch and mount (driver's side):
(http://i223.photobucket.com/albums/dd31/sencraig/000_0460-1_zpshvxmvvod.jpg)
Here is a 6 cyl perch and mount, passenger side:
(http://i223.photobucket.com/albums/dd31/sencraig/000_0404_zps38347d85.jpg)
6cyl driver's side:
(http://i223.photobucket.com/albums/dd31/sencraig/000_0406_zps78f1305c.jpg)
So, basically the perch is a tower/extension to the frame that the mounts bolt to. Some cars use them, some don't. i think the smaller monte carlos and camaros, for example do not use them----the mounts bolt directly to the crossmember in those cases ( i think?).
The v-6 and v-8 perches WILL NOT interchange without serious modification as in using a cutting torch and welding as the 8 has 2 bolts to the top of the frame and 2 bolts to the crossmember, whereas the 6 has 2 bolts to the top of the frame, 1 bolt to the SIDE of the frame and one bolt to the crossmember.
Also, notice that the driver's side v-6 perch has the clamshell bolted to it (instead of usually the mounts bolt to it) and the passenger side v-6 perch has the mount bolted to it. i think the reason why they did this is because the v-6 shakes at idle, but i'm only guessing here. But with v-8, both clamshells bolt to the engine and mounts bolt to the perches.
One more question, am I correct that the photos show the perch/mounting location for the V6? Are the holes to the right in the frame and crossmember where the V8 perches would mount?
-
Yes, the 2nd and 3rd pictures are v-6 and the new perches would have to be moved forward about 4.5". There should already be holes drilled for the v-8 perches.
-
Thanks, I very much appreciate the help!
-
Here is a picture showing the top mounting holes on a 1986 C10
Green arrows V-6 orange is where the V-8 ones go. I am eventually doing the same to mine
-
Nice! What about the crossmember? Is there another hole it attaches to there?
-
Nice! What about the crossmember? Is there another hole it attaches to there?
Yes. As you can tell where the V-6 mounts with 3 bolts the V-8 has 4 bolts and all the cross members have the needed holes. Stewart's frame never had a V-6 as they were 85 and newer so he had to drill
-
On a different note, I've been looking for a 350 TBI/TH400 transmission chip or ECM for the computer side of things and the only thing I've found is this: http://www.ebay.com/itm/121952331798?_trksid=p2055119.m1438.l2649&ssPageName=STRK%3AMEBIDX%3AIT (http://www.ebay.com/itm/121952331798?_trksid=p2055119.m1438.l2649&ssPageName=STRK%3AMEBIDX%3AIT)
I don't really care about the performance, more than it doesn't mess anything up. Also, the listing says "4 speed" and I'm almost certain the TH400 is a 3 speed.
Anyone have any insights?
-
http://tbichips.com/
read this guys site. a lot more credible imo
-
i'm not sure what would be the best plan-----to get the 350 settled in the chassis first? Or to worry about all the electronics?
i am pretty sure, but not 100% positive,that the injectors between the 6 and 8 are different and also the chip may need to be swapped out. i don't have time to research right now.
i think they can help:
http://howellefi.com/
i think one one (or both) of the Howell brothers worked at GM on the original TBI system.
-
Actually, it's probably best i withdraw from discussing fuel injection as i don't have much experience with it.
i can still help with actually swapping the engine in though.
-
Thanks guys, from my research it looks like I do need the bigger injectors (already sourced) and a new 350/turbo 400 computer chip (haven't found that one yet).
I have, however, thought of some more questions.
1. Do I need a whole new radiator brace for the bigger V8 unit, or will the bigger radiator fit in the one that I have?
2. Any ideas where to find those V8 motor perches? I've so far not had any luck with that, seems that local junkyards are pretty picked over for Chevy V8 vehicles of this era.
3. Will I have any problems with the stock fuel pump supplying enough pressure for the bigger injectors?
On the build front, I picked up a well worn high-mileage TBI 350 from an early 90s Chevy truck complete with intake manifold, throttle body, and injectors for $150! Score! The motor is now at a local rebuild shop and will be coming back a new engine, then the real fun begins!
-
1) have no idea
2) i thought i saw some online, will pm asap. i would give you mine but they are original to the truck. Plus, i may want to switch back to 8 someday.
3) no idea, but probably ok since all TBI systems need about 12lbs irregardless of engine size.
-
Thanks for the help, and if you do come up with any sources for those perches I'd be much obliged!
-
Hi guys, I just wanted to say thanks for the help! It took longer than I'd hoped (what with work, family, and life) but the dying 4.3 is gone and a fully rebuilt 350 is now in place, and running nice! Thanks again!
-
Yay! Good for you. Good job.
Where did you end up getting the engine perches from?
-
My brother worked at a junkyard and he managed to pick some up for me. Again, thanks for the help!