Motor swap in my '83. Benefits to a 87+ motor?

[sickquad]

So, I'm doing a engine swap in my 83 k20. Large variety of used motors around locally. I am wondering if I should pick up a 87+ motor and put my carb and manifold on it.

Anybody know if these motors are any better or should I stay with my original vintage? I believe my alt, water pump, exhaust... will bolt right up.

I'm thinking the only benefits are the centerbolt valve covers and found out the motors have about 20hp more.

I'm not interested in a TBI swap just yet, only a new motor.

Any suggestions will be appreciated.

 

[Hogback Fabrication]

IMO it doesn't matter much.

The newer motors may make a little more power due to better heads but the castings are a little thinner IIRC and most 87+ blocks have 2 bolt mains (the earlier truck SBC's were all 4 bolt mains).

The 87+ block will have provisions for a roller cam if you choose to go that route someday and the centerbolt valve covers are better (though it probably shouldn't matter). The newer block will have a 1 piece rear main seal as well which is much less likely to leak.

If they are the same price, I would go with the newer motor. The seals and design are better, but the differences between the two aren't all that big.

 

[Thunder]

There are diferences in 87+ 350 motors.
TBI Cars and 1/2 ton trucks/Blazers ect got light duty 210 HP, 2 bolt main with 64cc 9.2 to 1 compression ratio heads. (193)
3/4 ton and up trucks & vans got 195 HP heavy duty,4 bolt main, and had 76cc 8.2 CR heads (191)
You will have to modify the center holes in your older carb manifold to fit the newer heads. Because the center bolts on TBI heads go in at a flatter angle than the older heads.
If you get a motor that had a serpentine belt. You have to swap in an older water pump if you run V belts. Because the serp belt motors have reverse rotation water pumps.

 

[4X4HIGH]

If you choose an "86" engine then your existing intake manifold will bolt right on and you'll end up with a one piece rear main engine which means less chances of oil leaks. If you go "87" and later then you get centerbolt valve covers and you'll need to modify your intake as already stated.

 

[sickquad]

Good info, thanks guys. Sound like I'm going to go with the best motor I can find.

Now comes the guess work of buying a used motor. I think I found a low mile goodwrench motor.

 

[4X4HIGH]

You might want to PM Greg72 and see what he still has left to offer. He is close enough to you that i'm sure you could go pick one up (assuming he still has one). Anything you buy from Greg will be good.

 

[scrappyk5]

My 1984 blazer has a 1987 motor in it. The previous owner put all the intake, exhaust , and accesories from the 1984 motor onto the 1987 motor. I am not sure if he redid the intake manifold , but i have put almost 100,000 miles on the motor without a problem. I do know that he put an inline fuel pump and regulator on it. It does burn rich and I have turned down the gas mixture as much as possible. But all in all , I am not complaining.