I may have the chance to pick up a complete engine
from an 86 vette ( I have a 90 vette with 120k on it) .

My question is , are the 86 and 90 engines identical ?

I was thinking of getting the 86 and rebuilding it and
swap it into my car and hold onto the original engine
for another backup in the future .

the pictures of the engine looks just like mine .
the owner is asking $ 900 , and it looks like a complete
engine from the pictures .

The 86 could have either iron or aluminum heads. The 86 would have the MAF (mass airflow sensor) on the intake tube and the 90 was switched to an air intake speed density system that mounts on the plennum. Camshafts were different and the stock 90 engine made 245 hp or 250 hp (for coupes with 3.07 rearend ratio) versus the 230 to 235 hp 86.

Engine blocks should be the same except for the cams. That's a few of the differences I know of. I am just a rookie on this stuff but have a 90 so am familier with it. I am sure there are more as others will chip in.

You could just freshen up your 90 like JeffK is thinking of doing. See his Dreaming of a new engine, thread today for more info on this.

They are not identical but it should be an easy swap...

Joe

What Joseph said... they are not identical...

However, the 86 has flat tappets, versus roller hydraulic lifters. All verts and the last 8000 or so coupes had aluminum heads, this engine could very well have iron heads.

86 was the first year for the 1 pc rear main seal.

One other minor detail, and this depends on if your DMV checks, or, you have some process (emissions testing) that would (could) check. Technically, it is against the law to replace with an older engine. If you have a MY1990 vehicle, you must replace with engine from same MY or newer. Just and FYI.

Generally speaking, the L98 isn't all that uber-special an engine. It's mass produced and every GM product used it on one shape/form or another. The heads and intake were all that changed.

Unless you get into pickups, where they had 4-bolt mains.

If it was my project, I would look for a later block (from a truck) or get one and have it converted to 4 bolt mains.

Oh, another detail, truck engines are illegal in cars (damned EPA), but if your area doesn't check, well, it doesn't really matter, eh?

In short, $900 seems high for a motor you are going to rebuild. You really only need a shortblock to build from.

Thanks , That is exactly what I needed to hear .

I am better off finding a good short block and swap from there .

I didn't know this , but are truck engines built much stronger ?

I have no testing in FL . So would a truck block 4 bolt main be an ideal block to use ?

Thanks for the tips.

For a stock application you will notice zero difference between a 2 bolt and 4 bolt main. Buy what's available, imho.

Matthew

If there is no testing, then you should have no issues. FL is so damned lax with title requirements, I don't even think there is a transfer inspection!

I don't remember the details of build years and such when it comes to blocks, however, a small block with 4 bolt mains is stronger than a 2 bolt main.

Please realize, you can machine a 2 bolt block to 4 bolt. It doesn't cost much, but wlil need new main caps.

Florida is very lax ! you can build just about anything and put it on the road . I've seen some crazy stuff .

I used to live in NJ and you would fail inspections if you sneezed in the car . Much better here in FL.

Thanks for the info , I am also following the other thread
great info there too.

NJ no longer has inspections, only for emissions.

For what it's worth, original poster may be better off with a nice crate 350 from Jegs...

or a GMPP 383.