1976 chevy c10 250 Inline six 3 spd manual to 350 v8 th350 auto tran swap help

[DIG]

Let me start off by saying I am a noob, I am NOT a mechanic and I dont want to be one but I do need to swap the engine from my 1976 chevy c10 with a 250 inline six with a 3 on the tree saginaw manual transmission to a 350 v8. Now I dont want just any regular 350 v8. Preferably I would want one with over 250hp and 300trq from factory and MUST be carbureted  but I need more information. Information like engine mount placement, transmission compatibility , clutch bell housing compatibility and other issues that might arise from the swap. If anyone has a chart or something that can show compatible engines and the factory horsepower and torque that I want then that would be amazing. I have a chart that spans from 70-96 but I wonder if older engines wouldnt be better for my use case. Another thing I want to know is if a th350 auto trans will bolt right onto my current engine and if I would need to change driveshafts, steering columns or anything else.

The whole purpose of all of this is to save money. I need a new clutch kit which would run $60-$100 which is fine if a v8 could bolt right up using the same clutch kit. If not, then could the current clutch bell housing accept the proper clutch kit for the v8. If the case is neither then would a th350 or perhaps better automatic transmission that can be had for cheap used be a better option for me? I personally would prefer auto trans for daily driving and roadtrips but I do want to do some hauling and light offroading.

As far as Im aware the 350 v8 has 15mpg city? under normal driving conditions. My 250 i6 got less than that before (closer to 10mpg) I rebuilt the carb and replaced the mechanical fuel pump but Ive done some research and it appears that a lot of ppl are getting around the same mpg. So I figure why use a weaker engine that uses more gas that needs repairs right?

So the long and short of it is, First I need to know which years 350 v8s have 250HP+/ 300TRQ+ from factory and are carbureted and have as little electronics as possible. Second, which ones would be compatible with my current transmission and clutch OR which ones would bolt in easiest. Then third, would be if a th350 or similar auto trans would bolt into my truck without having to change the driveshaft and if I do need to change the driveshaft would that same one work for the 350 v8 + th350 configuration. Or if a 350 v8 would bolt onto my current 3 speed using the same size clutch kit. Which I believe is an 11 inch. How would I check that?

[zieg85]

I can tell you a short tail TH350 is the same length and spline as the manual transmission.  I haven't swapped a square body I-6 to V-8, just a 1972 and a 1964 and both worked fine with the existing frame perches.

[JohnnyPopper]

Your truck is compatible with all the combos GM came out with, that is the hidden beauty of this series.

If your coin is the real issue, you need to consider the extra costs beyond mounts and clutches.

TH350 require cooling lines and a radiator that has an internal cooler, or you can bolt on an external cooler.
However, the radiator you have may not be large enough to cool a v8. Count the rows of cooling tubes, you will need at least 3.

The v8 will need a flywheel, not sure if the i6 you have is compatible with a v8. Someone here will pry weigh in.

If you are the same guy with the clacky clack tappets, it sounds like your i6 is just tired and could used a rebuild. You should be getting better mileage then 10. 

Since you plan to ditch the i6, you might see if there is any hope by pulling the head and measuring the wear at the top of the cylinder...

There I go giving mechanical direction to someone who doesn't want to be one!!! 

Cheapest, most trouble free, back on the road sooner route is find a good running i6, take a compression test AFTER you hear it run, and possible drive, then BUY IT. done and done

Or buy a truck that has what you want. They're all over the place...

[DIG]

Thanks guys! This is some really helpful information! I am going to be running the engine like it is now (forgot to say that I got the lifter noise down quite a bit) until it breaks basically. I think the ol gal has some fight left in her but Im just done patching up a weak engine. Im only 23 and I want something with a little more grunt and part availability. This vehicle will be the one I drive until I die hopefully! That being said I actually dont even have a drivers license yet. I have had some serious health issues since I was 12 and havent felt healthy enough to drive until now. Its quite the story and a momentous accomplishment on my part to have even gotten this far with the truck. Just spent $80+ on new front brakes due to a malfunctioning caliper piston. We took the truck for a test drive and the brakes locked up. I have some more tinkering to do with them tomorrow as they are still touching the rotor even with new calipers. Im reusing the old pads as they are like brand new even though they are a few years old.  Currently I have been keeping my eye out for a good deal on a donor truck but none to be seen here in michigan. Also any year that would have the engine I want wont have the same body parts as mine but maybe thats not a big problem as most of the panels are in good shape. Just the rockers, floor pans, and cab corners are rusted out. Thats the next issue I am going to try and tackle, but first I must learn to weld! I really like welding so that I dont mind knowing how to do haha.

So if I understand you correctly:

1. any V8 will bolt into my truck without needing to swap mounting brackets?
2. I need a bigger radiator that has an auto trans radiator inside it? or get a separate radiator for the trans?
3. I need a flywheel, aka the big metal gear thing? I have one in the back of my truck as well as a torque converter and a 4 barrel Holley carb. I originally had a v8 and a th350 or 400 to go into the truck but when we lost our house due to the bank committing deed fraud we had a neighbor store some of our stuff and traded him some stuff to fix the truck but he never did. Then when he moved he had the truck stored at his neighbors and now he has the rest of our stuff and we cant find him. Lesson learned dont "censored word's will get you removed from this forum" trust anyone!
4.When the truck blows up I will take it apart for fun to see what went wrong.
Zieg85 when you say short tail th350 is the same as the manual does that include the clutch bell housing?

As for costs go, I am willing to put money into a new setup if its going to give me better reliability, longevity and POWER! I am trying to get it road worthy so I can get my drivers license and start driving. Then maybe get a job if my health keeps getting better. Right now it takes me all day just to do a simple task on the truck and it completely destroys me. You guys probably dont care about that stuff tho lol.

[JohnnyPopper]

Thanks for the time you took to make us aware of what your life is like.

Sounds like you will be OK, you have the determination and more importantly, a sound mind and strong vocabulary.

Reliability and longevity are common on a well maintained engine. Power comes from displacement or Cubic Inches.

Having said that, I have seen guy put race cams in Inline 6 engines...

Interchangeability of the power plants is relative to the chassis alone. You have to have the right parts and pieces, which calls for research depending on the package you decide on.

The small block Chevy V8 has had the same bolt pattern since 1955, so your truck is in the sweet spot of interchangeable engines and transmissions,  from I6, to V8, Manual to Auto/OverDrive. (OD is the way to go)

Hang in there lad, life is going to get more and more exciting...

[DIG]

Thanks that means a lot! Yeah I guess next step is keeping my eye out for a good deal on a decent engine and trans or donor truck. I guess I won't bother with messing with the clutch until I know more about which choice I'm gonna make.

Sent from my SM-G965U using Tapatalk

[DIG]

I will just continue using this thread for my newest transmission/engine conundrum that I am having. After getting everything we already talked about on my noisy lifters thread, I took the ol gal out for a spin and she was pulling hard to the left. Turns out my caliper was seized. No big deal right? WRONG! It turned out to be a huge ordeal. Costing well over $100 in parts. Had to replace both calipers, replace both hoses and the drivers side hard line to the proportioner. Reset the proportioner, bleed the lines about 6 times. Two quarts of brake fluid. Stupidity on my part etc. Turns out I didn't know that the brakes drag a little no matter what. Now I was trying to turn the rotors by hand after bleeding the brakes not knowing its dang near impossible. Put the tire on and she moves Ok with one hand. I was expecting them to just spin around with barely any effort. Turns out that's not how they work. So I put the wheels back on and go for yet another test drive about a month later. Brakes work fine, no pulling, no noticeable dragging and little heat on the rotors.

Now for why I am here...the truck struggles to move forward, up slight inclines and won't exceed 25mph no matter what gear she's in. She's running rough, like she just can't seem to get her feet under her. At times it feels like she finally gets smooth but then a few seconds later were back to I think I can mode. Now this sounds like a clutch slipping issue to me, please correct me if I am wrong. It seems to me that it is not fully connecting with the fly wheel and the transmission isn't getting the power it needs. Shifts into gear just fine but just won't Go right.

As previously stated I would eventually like to swap out both the engine and trans. Having nowhere to go from here without getting a new clutch kit for around $100 I see myself at a dilemma. Do I just get the clutch kit and learn how to drive using a manual or do I just bite the bullet and swap in the automatic th350 now? Depending on the cost and condition of a second hand/junk yard th350 I would like to go with that. However there are several factors that go into that cost other than just the trans itself. I would need a new steering column or linkage kit (I do want a tilt column anyways). An automatic trans radiator, either separate or built in. My radiator may or may not be viable for that I will have to check. Also possibly a new drive shaft depending on what model of trans I get, short or long tail. Now the obvious answer here is donor truck. Which I hear ya loud and clear! But unless I can get my friend who gives me $100 a month as charity to give me a year advance I don't see me being able to do that. I am also lacking a lot of tools required for this job. I need an engine hoist and stand, which I used to have but we had to store things with a neighbor when the bank took out house due to bank fraud (they frauded us) and he moved and we lost contact with him. I found him on Facebook and am messaging him to see if he still has my stuff and if I can get it back but no reply yet. I also need a 3 ton High lift jack, jack stands and probably numerous other tools I am missing. Now I recently learned about head's and crank shafts and how much power they can give you. So which year of engine has now become less important to me and more so on the cost and condition. If I have to go junk yard engine, then a rebuild is almost a given. But with a well cared for Facebook engine I might be able to just drop it in and use it. All that being said I believe my engine is still just fine until I can afford to buy an engine and all the parts and tools needed to do a swap.

TLDR: should I just buy the clutch kit for around $100 or should I swap in the automatic now if I can get the parts cheap. Say under $350 for radiator, lines, transmission and tilt auto steering column. Also how much does a trans rebuild cost and is it worth doing?

Thanks in advance, I really appreciate all the help and knowledge. As much as I hate working on cars it is rewarding to think that I did all of this on my own just so I can drive and hopefully one day get a job and a wife all with this truck by my side until I die.

[DIG]

I ended up going with the clutch kit due to financial issues and lack of tools. I'd rather spend $100 and have the truck driving than let it sit another 6 months.