[dare79]

I recently bought this truck and trying to figure what engine size it has. I have done some research and narrowed it down to three engine sizes 302,327,350. My only concern is when I need to buy parts what engine size do I use, or are they all interchangeable? Here are the numbers I have located so far, any info will help thanks.

Engine: 3970010 (Back)
12S251168 (Front of passenger head)

Intake Manifold: 346250

Heads: 333882

P.S. All these numbers seem to bring up different engine sizes, how do they all work together. Is there anything anyone would change? Thnks again

[Sinister]

My guess is it's a 350.

[va4cqd]

likely a mid 70s 350

[bigdog7373]

If it's a 1968 block, it's a 327, but thats rare in an 80's truck. It's probably the 69-79 block which is a 350. http://www.nastyz28.com/sbchevy/sblock.php

[Torque454]

No 302s or 327s in the 80s. I dont think the 302 or 327s have been made since the 60s and i'm not sure they ever made it into a truck anyways? Maybe the 327 did i dunno. Anyways its possible that the older engine was put into your truck but most likely its still a 350. I rarely see a 327 and even more rarely see a 302.

The only way to know for sure would be to pull the heads and check the bore and stroke. If it measured 4" bore and 3.50" stroke then its a 350. (its actually 3.48" but you wont be able to tell .020" with a ruler or tape measure)

[va4cqd]

someone swapped that engine in the truck for sure. you won't find a 70s engine in an 87 truck from factory. the original engine would have been a 1 piece rear seal with center bolt heads and throttle body fuel injection

[Torque454]

Yep, 86 was the first year for the centerbolt heads and 1 pc rear oil seal. I believe they changed to a shallow groove oil ring or something like that as well.

Then in 87 they got the TBI.

An 0010 block would be from the 70s. Had it not been 4am id probably have pointed this out.

The 0010 engines never had centerbolt heads, they had 2 pc main seals and they never had fuel injection

[dare79]

So when buying parts for my engine do I just pick a year from the 70's since the original engine was swaped out? Thank you all for your help.

[DoubleVision]

Clean off the front pad on the passengers side block deck, right behind the alternator. There you will find the suffix code that will look something like this:
HTC We can then look up that suffix code and tell you what you have and what it came out of. Paint maybe partially covering it so you can`t see it.
Fully, it appears like this V1123HTC as a example.

[Torque454]

Originally Posted by dare79

So when buying parts for my engine do I just pick a year from the 70's since the original engine was swaped out? Thank you all for your help.

That depends on what the part is. If you have the serpentine belt setup like i think your truck should have, then you would want to order parts for the 87. The water pump and alternator and stuff are not the same as the ones with v-belts.

Did they swap the fuel injection onto this older engine or is it carbed? If you dont know the difference, the TBI looks alot like a carb, but it is not a carb. There will only be two barrels if its TBI and most likely 4 if its carb.

If its carb then youd probably order any other part from a 70s pickup. If its swapped to fuel injection then youd order parts for the 87. I'm betting they converted it to carb tho.

[dare79]

Here is a pic of the engine. The carb is also a edelbrock. The only numbers i found on the pad behind the altenator were 12S251168 to the left of the pad and 116 on the right side.

[va4cqd]

someone just slapped in a 70s 350. the front accessory drive is correct for an 87 model year

[DoubleVision]

It appears you have a edelbrock carb on a stock intake with a adapter plate. Big mistake. Adapters are junk and the best place for them is the trash. It would run alot better with a edelbrock performer intake or a Quadrajet on the stock intake. Adapters disrupt the mixture and the vacuum, they also kill low end power. Does the distributor have a vacuum advance?

[sbchevfreak]

You will also want to plug that HUGE hole in the exaughst manifold on #1 cylinder.

[Torque454]

That looks like some kind of serpentine belt on the water pump and alternator and a v belt on the power steering pump. Is that accurate?