Chevy 350 questions carb to TBI

[beretta]

I recently picked up a 1968 350 engine. not sure if its 4 bolt or not. its a 010 block. complete to carb, has 2 barrel so just a guess its probably only 2 bolt main. Aprox 65,000 original KM

I have a tbi intake, throttle body and wire harness and ecm out of a 87 chevy truck... First year fuel injection but same 80's style.

I have a 85 4x4 im putting this engine into, and converting to fuel injected.

Problems i have had in the past with older engines is starting to smoke after a couple months of running, im assuming from valves .

So what i want to do is throw on a newer set of heads. pretty much anything i find at the wreckers hoping ill find something with lower millage. anything 88 and up that way i dont have to drill the center holes on my intake and worry about the old heads and valves burning out.

The engine block will remain stock for now, stock cam ect.
Few questions or suggestions im looking for is choosing a decent pair of heads to put on this with my TBI intake.

If i put 305 heads on i know it bumps the compression slightly, but what could be some pro's and cons about this..
My chances of finding a vortec at the wrecking yard is probably slim, there normally is a hole line up of mid 90's pickups there. would there be a specific head i should stay away from or try to find.

Im not looking to make a race engine, i just want it to run and be reliable and be cheap as possible to get it up and running.

I traded a 1970's elelbrock street master aluminum intake i had and a holley 600cfm carb for this engine straight up.
I have rolled it over by hand a few times and dumped a bunch of oil in it. no flywheel on it right now so i havent got around to throwing a starter on it and doing a compression test, but it feels strong turning it by hand.

[scd88ga]

Depending on the pistons, cam and heads that are on that "010 68 motor, it could be anywhere from 145hp all the way up to 375hp! But being originally a 2 barrel carb, it is more than likely on the lower end of that spectrum, lol! That casting was used from 68-79 and could be a 2 bolt or 4 bolt main, and other casting numbers on the block will tell you the % of the content of nickel used in that block! High nickel blocks are stronger and more desirable! If you want more info from me, you're going to need to look over the block and heads and get me more of the casting numbers, so I can decode exactly what you have.

Below is an image that will tell you where to look! In addition to the photo, the numbers under the timing cover are useful, so if you could get those too?




I have built 6 SBC's this year alone and have lost count on how many total I have built over the years, lol! Once you get me a little more info, I will be able to better help you out with part recommendations for your build. Thanks!

[woody90gtz]

A '68 350 should have decent compression. But that would be the first thing to find out (pistons). Swirl port TBI heads would be fine for you since you already have the right intake. Depending on your CR on the '68 engine, you could use 305 (#187) or 350 (#193) heads. 305 heads will bump the compression a little bit, but the have smaller intake valves that do choke a 350. My truck actually had 305 heads on it and it was a dog...but it also had cheapo ashtray pistons and thick gaskets for only 8.7:1 compression.

I converted mine to Vortec heads, but that takes a different intake manifold from GM ($400) or an aftermarket card Vortec manifold and TBI adapter (which is the route I went.)

Unless you want to spend some time with the computer, I'd stick with the TBI heads. Untouched 350 heads if compression is good, and maybe 305 heads if the compression is on the low side, although intake port flow will be reduced. You can machine the 305 heads for 1.94 350 valves for the best of both worlds...and it's some cheap insurance for valve sealing.

[scd88ga]

In addition to my comment above, my buddy may still have a nearly new take-off set of nicely rebuilt cylinder heads off of a 1992 TBI 350 truck motor! I'll give him a call and see if he still has them!

[beretta]

I dont want to spend alot of money on heads, just an idea what i could find at the wreckers that will work decent for what i have.
I also have a 4 bolt main bare block you can still see the cross groves in the cylinders but its not a 010 block its prob from the 80's.

The 010 i got is complete minus the distrib. and it has crapy old heads, not camel humps or anything special i think they are a half triangle or something on the front of them. i just know if i run it as is i will have problems half way through the winter with it smoking and burning the valves up.

My truck is also a 4 speed bow low with 3.08 gears. so bumping compression for some lower end torque probably isnt much of an issue for me LOL, ill see what i can find for 350 heads, just wasnt sure if there is some i should stay away from or if all early 90's trucks used all the same head.

Id like to pull the heads and have a better look inside but also dont want it sitting for long with it apart since its sitting outside and i dont have a garage at home. dont really want to pull the oil pan either... if its not going to leak oil i would rather just leave it for now.. our work truck i had put 2 sets of oil pan gaskets in it and it still leaked i dont know why, i finally broke down and got a 1 piece gasket and it still leaks, maybe the oil pan is warped or something LOL. but if its not leaking then im not messing with it right now, i already assume its 2 bolt main and not worried if its 2 or 4 i have no reason to pull the pan.

Just want to slap some heads on it, my intake and throttle body and drop it in my truck.. Im not sure if it was an auto or manual car this engine came out of.. last time i done anything like this swap was in my 84 firebird with a 2.8 v6 the engine i had picked up was in a truck and fuel injected and was manual, i converted it all to carb and put my flywheel on it, the truck manual flywheel was thiner ( it think) and if i used it my clutch wouldnt have disengaged so i had to use the one for the car. the engine had a nasty vibration. never did get rid of the vibration until my bell housing broke off of the engine after a month of driving it. almost 100% certain the vibration was from the flywheel not being balanced to that crank. just hope i dont have vibration problems with this one.